1.1 Functional purpose and technical characteristics of the part
To compile a quality technological process Before manufacturing a part, it is necessary to carefully study its design and purpose in the machine.
The part is a cylindrical axis. The highest demands on the accuracy of shape and location, as well as roughness, are placed on the surfaces of the axle journals intended for seating bearings. So the accuracy of the journals for bearings must correspond to the 7th grade. High requirements for the accuracy of the location of these axle journals relative to each other arise from the operating conditions of the axle.
All axle journals are surfaces of rotation of relatively high precision. This determines the feasibility of using turning operations only for their pre-treatment, and final processing in order to ensure the specified dimensional accuracy and surface roughness should be performed by grinding. To ensure high requirements for the accuracy of the location of the axle journals, their final processing must be carried out in one installation or, in extreme cases, on the same bases.
Axles of this design are used quite widely in mechanical engineering.
The axles are designed to transmit torque and mount various parts and mechanisms on them. They are a combination of smooth landing and non-landing, as well as transition surfaces.
The technical requirements for the axes are characterized by the following data. The diametric dimensions of the landing journals are made according to IT7, IT6, other journals according to IT10, IT11.
The design of the axle, its dimensions and rigidity, technical requirements, production program are the main factors determining the manufacturing technology and the equipment used.
The part is a body of revolution and consists of simple structural elements, presented in the form of bodies of revolution round section various diameters and lengths. There is a thread on the axle. The axle length is 112 mm, the maximum diameter is 75 mm, and the minimum is 20 mm.
Based on constructive purpose parts in a car, all surfaces of this part can be divided into 2 groups:
main or work surfaces;
loose or non-working surfaces.
Almost all surfaces of the axle are considered basic because they interface with the corresponding surfaces of other machine parts or are directly involved in the working process of the machine. This explains the rather high requirements for the accuracy of part processing and the degree of roughness indicated in the drawing.
It can be noted that the design of the part fully corresponds to its service purpose. But the principle of manufacturability of design is not only to satisfy operational requirements, but also the requirements for the most rational and economical manufacture of the product.
The part has surfaces that are easily accessible for processing; sufficient rigidity of the part allows it to be processed on machines with the most productive cutting conditions. This part is technologically advanced, since it contains simple surface profiles; its processing does not require specially designed devices and machines. The axle surfaces are processed using turning, drilling and grinding machines. The required dimensional accuracy and surface roughness are achieved with a relatively small set of simple operations, as well as a set of standard cutters and grinding wheels.
Manufacturing a part is labor-intensive, which is associated, first of all, with ensuring technical specifications work of the part, required dimensional accuracy, roughness of working surfaces.
So, the part is technologically advanced in terms of design and processing methods.
The material from which the axle is made, steel 45, belongs to the group of medium-carbon structural steels. Used for medium-loaded parts operating at low speeds and medium specific pressures.
The chemical composition of this material is summarized in Table 1.1.
Table 1.1
| 7 | ||||||||
| WITH | Si | Mn | Cr | S | P | Cu | Ni | As |
| 0,42-05 | 0,17-0,37 | 0,5-0,8 | 0,25 | 0,04 | 0,035 | 0,25 | 0,25 | 0,08 |
Let us dwell a little on the mechanical properties of rolled products and forgings, necessary for further analysis, which we will also summarize in Table 1.2.
Table 1.2
Let us give some technological properties.
The temperature of the beginning of forging is 1280 C°, the end of forging is 750 C°.
This steel has limited weldability
Machinability by cutting - in the hot-rolled state at HB 144-156 and σ B = 510 MPa.
1.2 Determining the type of production and batch size of the part
The assignment for the course project indicates an annual product production program in the amount of 7,000 pieces. Using the source formula, we determine the annual production program for parts in pieces, taking into account spare parts and possible losses:
where P is the annual product production program, pcs.;
P 1 – annual program for manufacturing parts, pcs. (we accept 8000 pcs.);
b – the number of additionally manufactured parts for spare parts and to make up for possible losses, as a percentage. You can take b=5-7;
m – the number of parts of this name in the product (accept 1 piece).
pcs.
The size of the production program in physical quantitative terms determines the type of production and has a decisive influence on the nature of the technological process, on the choice of equipment and tooling, on the organization of production.
In mechanical engineering there are three main types of production:
Single or individual production;
Serial production;
Mass production.
Based on the production program, we can come to the conclusion that in this case we have mass production. In mass production, products are manufactured in batches or series that are repeated periodically.
Depending on the size of batches or series, there are three types of batch production for medium-sized machines:
Small-scale production with the number of products in a series up to 25 pieces;
Medium-scale production with the number of products in a series being 25-200 pieces;
Large-scale production with the number of products in a series exceeding 200 pieces;
A characteristic feature of mass production is that products are manufactured in batches. The number of parts in a batch for simultaneous launch can be determined using the following simplified formula:
where N is the number of blanks in the batch;
P – annual program for manufacturing parts, pcs.;
L – the number of days for which it is necessary to have a supply of parts in the warehouse to ensure assembly (assuming L = 10);
F – number of working days in a year. You can take F=240.
pcs.
Knowing the annual production volume of parts, we determine that this production belongs to large-scale production (5000 - 50000 pcs.).
In mass production, each operation of the technological process is assigned to a specific workplace. Most workplaces perform several operations that are repeated periodically.
1.3 Choosing a method for obtaining a workpiece
The method for obtaining initial blanks of machine parts is determined by the design of the part, the production volume and production plan, as well as the cost-effectiveness of manufacturing. Initially, from the variety of methods for obtaining initial blanks, several methods are selected that technologically provide the possibility of obtaining a blank for a given part and allow the configuration of the initial blank to be as close as possible to the configuration of the finished part. Selecting a workpiece means choosing a method for obtaining it, setting allowances for processing each surface, calculating dimensions and indicating tolerances for manufacturing inaccuracies.
The main thing when choosing a workpiece is to ensure the specified quality of the finished part at its minimum cost.
The correct solution to the issue of choosing workpieces, if from the point of view of technical requirements and capabilities different types of them are applicable, can only be obtained as a result of technical and economic calculations by comparing the cost options of the finished part for one or another type of workpiece. Technological processes for obtaining blanks are determined by the technological properties of the material, the design shapes and sizes of parts and the production program. Preference should be given to workpieces characterized best use metal and lower cost.
Let's take two methods for obtaining blanks and, after analyzing each, choose desired method receiving blanks:
1) receipt of the workpiece from rental
2) obtaining a workpiece by stamping.
You should choose the most “successful” method of obtaining a workpiece by analytical calculation. Let's compare the options based on the minimum value of the given costs for manufacturing the part.
If the workpiece is made from rolled steel, then the cost of the workpiece is determined by the weight of the rolled stock required for the manufacture of the part and the weight of the chips. The cost of a billet obtained by hire is determined by the following formula:
,
whereQ is the mass of the workpiece, kg;
S – price of 1 kg of workpiece material, rub.;
q – mass of the finished part, kg;
Q = 3.78 kg; S = 115 rub.; q = 0.8 kg; S exhaust = 14.4 kg.
Let's substitute the initial data into the formula:
Let's consider the option of obtaining a workpiece by stamping on a gas-condensing material. The cost of the workpiece is determined by the expression:
Where C i is the price of one ton of stampings, rub.;
K T – coefficient depending on the stamping accuracy class;
К С – coefficient depending on the stamping complexity group;
К В – coefficient depending on the mass of stampings;
K M – coefficient depending on the grade of stamping material;
K P – coefficient depending on the annual production program for stampings;
Q – mass of the workpiece, kg;
q – mass of the finished part, kg;
S waste – price of 1 ton of waste, rub.
With i = 315 rub.; Q = 1.25 kg; K T = 1; K C = 0.84; K V = 1; K M = 1; K P = 1;
q = 0.8 kg; S exhaust = 14.4 kg.
The economic effect for comparing methods for producing workpieces, in which the technological process of mechanical processing does not change, can be calculated using the formula:
,
whereS E1, S E2 – cost of comparable blanks, rub.;
N – annual program, pcs.
We define:
From the results obtained it is clear that the economically advantageous option is to obtain the workpiece by stamping.
Production of a workpiece by stamping on various types equipment is a progressive method, as it significantly reduces allowances for machining in comparison with obtaining a workpiece from rolled stock, and is also characterized by a higher degree of accuracy and higher productivity. The stamping process also compacts the material and creates directionality of the material fiber along the contour of the part.
Having solved the problem of choosing a method for obtaining a workpiece, you can proceed to the following steps course work, which will gradually lead us to the direct compilation of the technological process for manufacturing the part, which is the main goal of the course work. The choice of the type of workpiece and the method for its production have the most direct and very significant impact on the nature of the design of the technological process for manufacturing the part, since depending on the chosen method for obtaining the workpiece, the amount of allowance for processing the part can fluctuate within a significant range and, therefore, it is not the set of methods that changes, used for surface treatment.
1.4 Purpose of processing methods and stages
The choice of processing method is influenced the following factors that need to be taken into account:
shape and size of the part;
processing accuracy and surface cleanliness of parts;
economic feasibility of the selected processing method.
Guided by the above points, we will begin to identify a set of processing methods for each surface of the part.
Figure 1.1 Sketch of a part indicating the layers removed during machining
All axle surfaces have fairly high roughness requirements. Grinding of surfaces A, B, C, D, D, E, Z, I, K is divided into two operations: rough (preliminary) and finishing (final) grinding. When rough turning, we remove most of the allowance; processing is carried out with a large cutting depth and high feed. The scheme that provides the shortest processing time is the most profitable. When finishing turning, we remove a small part of the allowance, and the order of surface processing is maintained.
When processing on lathe It is necessary to pay attention to the strong fastening of the part and the cutter.
To obtain the specified roughness and the required quality of surfaces G and I, it is necessary to use fine grinding, in which the accuracy of processing external cylindrical surfaces reaches the third class, and the surface roughness reaches 6-10 classes.
For greater clarity, let us schematically write down the selected processing methods for each surface of the part:
A: rough turning, finishing turning;
B: rough turning, finishing turning, thread cutting;
B: rough turning, finishing turning;
G: rough turning, fine turning, fine grinding;
D: rough turning, finishing turning;
E: rough turning, finishing turning;
F: drilling, countersinking, reaming;
Z: rough turning, finishing turning;
I: rough turning, fine turning, fine grinding;
K: rough turning, finishing turning;
L: drilling, countersinking;
M: drilling, countersinking;
Now you can move on to the next stage of coursework, related to the selection of technical bases.
1.5 Selection of bases and processing sequence
During processing, the workpiece part must occupy and maintain a certain position relative to the parts of the machine or device throughout the entire processing time. To do this, it is necessary to exclude the possibility of three rectilinear movements the workpiece in the direction of the selected coordinate axes and three rotational movements around these or parallel axes (i.e., deprive the workpiece of six degrees of freedom).
To determine the position of a rigid workpiece, six reference points are required. To place them, three coordinate surfaces are required (or three combinations of coordinate surfaces replacing them); depending on the shape and size of the workpiece, these points can be located on the coordinate surface in various ways.
It is recommended to choose design bases as technological bases in order to avoid recalculation of operational dimensions. The axis is a cylindrical part, the design bases of which are the end surfaces. In most operations, we base the part according to the following schemes.
Figure 1.2 Scheme of installing a workpiece in a three-jaw chuck
In this case, when installing the workpiece in the chuck: 1, 2, 3, 4 – double guide base, which takes away four degrees of freedom – movement relative to the OX axis and OZ axis and rotation around the OX and OZ axes; 5 – the support base deprives the workpiece of one degree of freedom – movement along the OY axis;
6 – support base, depriving the workpiece of one degree of freedom, namely rotation around the OY axis;
Figure 1.3 Scheme of installing the workpiece in a vice
Taking into account the shape and dimensions of the part, as well as the processing accuracy and surface finish, sets of processing methods were selected for each shaft surface. We can determine the sequence of surface treatment.
Figure 1.4 Sketch of a part with surface designations
1. Turning operation. The workpiece is installed on the surface 4 in
self-centering 3-jaw chuck with a stop at end 5 for rough turning of end 9, surface 8, end 7, surface 6.
2. Turning operation. We turn the workpiece over and install it in a self-centering 3-jaw chuck along surface 8 with an emphasis on end 7 for rough turning of end 1, surface 2, end 3, surface 4, end 5.
3. Turning operation. The workpiece is installed on the surface 4 in
self-centering 3-jaw chuck with an emphasis on end 5 for finishing turning of end 9, surface 8, end 7, surface 6, chamfer 16 and groove 19.
4. Turning operation. We turn the workpiece over and install it in a self-centering 3-jaw chuck along surface 8 with a stop at end 7 for finishing turning of end 1, surface 2, end 3, surface 4, end 5, chamfers 14, 15 and grooves 17, 18.
5. Turning operation. We install the workpiece in a self-centering 3-jaw chuck along surface 8 with an emphasis on end 7 for drilling and countersinking surface 10, cutting threads on surface 2.
6. Drilling operation. We place the part in a vice along surface 6 with emphasis on end 9 for drilling, countersinking and reaming surface 11, drilling and countersinking surfaces 12 and 13.
7. Grinding operation. The part is installed along surface 4 in a self-centering 3-jaw chuck with a stop at end 5 for grinding surface 8.
8. Grinding operation. The part is installed along surface 8 in a self-centering 3-jaw chuck with a stop at end 7 for grinding surface 4.
9. Remove the part from the fixture and send it for inspection.
The workpiece surfaces are processed in the following sequence:
surface 9 – rough turning;
surface 8 – rough turning;
surface 7 – rough turning;
surface 6 – rough turning;
surface 1 – rough turning;
surface 2 – rough turning;
surface 3 – rough turning;
surface 4 – rough turning;
surface 5 – rough turning;
surface 9 – finishing turning;
surface 8 – finishing turning;
surface 7 – finishing turning;
surface 6 – finishing turning;
surface 16 – chamfer;
surface 19 – sharpen the groove;
surface 1 – finishing turning;
surface 2 – finishing turning;
surface 3 – finishing turning;
surface 4 – finishing turning;
surface 5 – fine turning;
surface 14 – chamfer;
surface 15 – chamfer;
surface 17 – sharpen the groove;
surface 18 – sharpen the groove;
surface 10 – drilling, countersinking;
surface 2 – thread cutting;
surface 11 – drilling, countersinking, reaming;
surface 12, 13 – drilling, countersinking;
surface 8 – fine grinding;
surface 4 – fine grinding;
As you can see, the processing of workpiece surfaces is carried out in order from rougher to more precise methods. The last processing method in terms of accuracy and quality must meet the requirements of the drawing.
1.6 Development of route technological process
The part represents an axis and belongs to bodies of rotation. We process the workpiece obtained by stamping. When processing we use the following operations.
010. Turning.
1. grind surface 8, trim end 9;
2. grind the surface 6, trim the end 7
Cutter material: ST25.
Coolant grade: 5% emulsion.
015. Turning.
Processing is carried out on a turret lathe model 1P365.
1. grind surface 2, trim end 1;
2. grind surface 4, trim end 3;
3. trim the end 5.
Cutter material: ST25.
Coolant grade: 5% emulsion.
The part is based in a three-jaw chuck.
We use a bracket as a measuring tool.
020. Turning.
Processing is carried out on a turret lathe model 1P365.
1. grind surfaces 8, 19, trim end 9;
2. grind surfaces 6, trim end 7;
3. remove chamfer 16.
Cutter material: ST25.
Coolant grade: 5% emulsion.
The part is based in a three-jaw chuck.
We use a bracket as a measuring tool.
025. Turning.
Processing is carried out on a turret lathe model 1P365.
1. grind surfaces 2, 17, trim end 1;
2. grind surfaces 4, 18, trim end 3;
3. trim end 5;
4. chamfer 15.
Cutter material: ST25.
Coolant grade: 5% emulsion.
The part is based in a three-jaw chuck.
We use a bracket as a measuring tool.
030. Turning.
Processing is carried out on a turret lathe model 1P365.
1. drill, countersink a hole - surface 10;
2. cut the thread – surface 2;
Drill material: ST25.
Coolant grade: 5% emulsion.
The part is based in a three-jaw chuck.
035. Drilling
Processing is carried out on a 2550F2 jig drilling machine.
1. drill, countersink 4 stepped holes Ø9 – surface 12 and Ø14 – surface 13;
2. drill, countersink, ream a hole Ø8 – surface 11;
Drill material: R6M5.
Coolant grade: 5% emulsion.
The part is held in a vice.
We use a gauge as a measuring tool.
040. Grinding
1. grind the surface 8.
The part is based in a three-jaw chuck.
We use a bracket as a measuring tool.
045. Grinding
Processing is carried out on cylindrical grinding machine 3T160.
1. grind the surface 4.
Select a grinding wheel for processing
PP 600×80×305 24A 25 N SM1 7 K5A 35 m/s. GOST 2424-83.
The part is based in a three-jaw chuck.
We use a bracket as a measuring tool.
050. Vibroabrasive
Processing is carried out in a vibroabrasive machine.
1. blunt sharp edges, remove burrs.
055. Flushing
Washing is done in the bathroom.
060. Control
They control all dimensions, check the roughness of surfaces, the absence of nicks, and the dullness of sharp edges. A control table is used.
1.7 Selection of equipment, accessories, cutting and measuring tools
axis workpiece cutting machining
The choice of machine equipment is one of most important tasks when developing a technological process for machining a workpiece. The productivity of part manufacturing, the economic use of production space, mechanization and automation depend on its correct choice. manual labor, electricity and ultimately the cost of the product.
Depending on the volume of product output, machines are selected based on the degree of specialization and high productivity, as well as machines with computer numerical control (CNC).
When developing a technological process for machining a workpiece, it is necessary to correctly select devices that should help increase labor productivity, processing accuracy, improve working conditions, eliminate the preliminary marking of the workpiece and align them when installed on the machine.
The use of machine tools and auxiliary tools when processing workpieces provides a number of advantages:
improves the quality and accuracy of parts processing;
reduces the labor intensity of processing workpieces due to sharp decrease time spent on installation, alignment and fastening;
expands the technological capabilities of machines;
creates the possibility of simultaneous processing of several workpieces fixed in a common device.
When developing a technological process for machining a workpiece, the choice cutting tool, its type, design and dimensions are largely determined by processing methods, properties of the material being processed, the required processing accuracy and the quality of the processed surface of the workpiece.
When choosing a cutting tool, you should strive to use a standard tool, but, when appropriate, you should use a special, combined, shaped tool that allows you to combine the processing of several surfaces.
The correct choice of the cutting part of the tool has great value to increase productivity and reduce processing costs.
When designing a technological process for machining a workpiece, for interoperational and final control of machined surfaces, it is necessary to use a standard measuring tool, taking into account the type of production, but at the same time, when appropriate, a special control and measuring tool or control and measuring device should be used.
The control method should help increase the productivity of the inspector and machine operator, create conditions for improving the quality of products and reducing their cost. In individual and mass production, a universal measuring tool is usually used (vernier calipers, depth gauges, micrometers, inclinometers, indicators, etc.)
In mass and large-scale production, it is recommended to use limit gauges (staples, plugs, templates, etc.) and active control methods that have received widespread in many branches of mechanical engineering.
1.8 Calculation of operating dimensions
Operating means the size marked on the operational sketch and characterizing the size of the surface being treated or relative position processed surfaces, lines or points of the part. Calculation of operational dimensions comes down to the task of correctly determining the value of the operational allowance and the value of the operational tolerance, taking into account the features of the developed technology.
Long operational dimensions are understood as dimensions characterizing the processing of surfaces with one-sided allowance, as well as dimensions between axes and lines. Calculation of long operating dimensions is carried out in the following sequence:
1. Preparation of initial data (based on the working drawing and operational maps).
2. Drawing up a processing scheme based on the initial data.
3. Construction of a graph of dimensional chains to determine allowances, drawing and operational dimensions.
4. Drawing up a sheet for calculating operating sizes.
On the processing diagram (Figure 1.5) we place a sketch of the part indicating all the surfaces of a given geometric structure encountered during the processing process from the workpiece to the finished part. At the top of the sketch all long drawing dimensions and drawing dimensions with tolerances (C) are indicated, and at the bottom all operational allowances (1z2, 2z3, ..., 13z14). Under the sketch in the processing table there are dimensional lines characterizing all dimensions of the workpiece, oriented with one-sided arrows, so that not a single arrow approaches one of the surfaces of the workpiece, and only one arrow approaches the other surfaces. The following are the dimension lines characterizing the dimensions of the machining. Operational dimensions are oriented in the direction of the surfaces being processed.
Figure 1.5 Part processing scheme
On the graph of the original structures connecting surfaces 1 and 2 with wavy edges characterizing the amount of allowance 1z2, surfaces 3 and 4 with additional edges characterizing the amount of allowance 3z4, etc. We also draw thick edges of drawing sizes 2c13, 4c6, etc.
Figure 1.6 Graph of initial structures
Top of the graph. Characterizes the surface of a part. The number in the circle indicates the surface number on the processing diagram.
Edge of the graph. Characterizes the type of connections between surfaces.
"z" - Corresponds to the value of the operational allowance, and "c" - to the drawing size.
Based on the developed processing scheme, a graph of arbitrary structures is constructed. The construction of a derivative tree begins from the surface of the workpiece, to which no arrows are drawn on the processing diagram. In Figure 1.5, such a surface is indicated by the number “1”. From this surface we draw those edges of the graph that touch it. At the end of these edges we indicate arrows and numbers of those surfaces to which the indicated dimensions are drawn. Similarly, we complete the graph according to the processing scheme.
Figure 1.7 Derived structure graph
Top of the graph. Characterizes the surface of a part.
Edge of the graph. The constituent link of the dimensional chain corresponds to the operational size or workpiece size.
Edge of the graph. The closing link of the dimensional chain corresponds to the drawing size.
Edge of the graph. The closing link of the dimensional chain corresponds to the operational allowance.
We put a sign (“+” or “–”) on all edges of the graph, guided by the following rule: if an edge of the graph enters with its arrow into a vertex with a higher number, then we put a “+” sign on this edge; if an edge of the graph enters with its arrow into a vertex with a lower number, then we put a “–” sign on this edge (Figure 1.8). We take into account that we do not know the operational dimensions, and according to the processing scheme (Figure 1.5) we determine approximately the value of the operational size or the size of the workpiece, using for this purpose the drawing dimensions and the minimum operational allowances, which consist of the values of microroughness (Rz), the depth of the deformation layer (T) and spatial deviation (Δpr) resulting from the previous operation.
Column 1. In any order, rewrite all drawing dimensions and allowances.
Column 2. We indicate the numbers of operations in the sequence of their execution using route technology.
Column 3. Indicate the name of the operations.
Column 4. We indicate the type of machine and its model.
Column 5. We place simplified sketches in one constant position for each operation, indicating the surfaces to be processed according to the routing technology. Surfaces are numbered in accordance with the processing scheme (Figure 1.5).
Column 6. For each surface processed in this operation, indicate the operating size.
Column 7. We do not perform heat treatment of the part during this operation, so we leave the column blank.
Column 8. To be filled in in exceptional cases, when the choice of measurement base is limited by the conditions for the convenience of controlling the operating size. In our case, the graph remains free.
Column 9. We indicate possible options surfaces that can be used as technological bases taking into account the recommendations given in.
The selection of surfaces used as technological and measuring bases begins with the last operation in the reverse order of the technological process. We write down the equations of dimensional chains using the graph of the original structures.
After selecting the bases and operational dimensions, we proceed to calculating nominal values and selecting tolerances for operational dimensions.
The calculation of long operating dimensions is based on the results of work to optimize the structure of operating dimensions and is carried out in accordance with the sequence of work. Preparation of initial data for calculating operating sizes is carried out by filling out the columns
13-17 maps for selecting bases and calculating operating sizes.
Column 13. To close the links of dimensional chains, which are drawing dimensions, we write down the minimum values of these dimensions. To close the links that represent operational allowances, we indicate the value of the minimum allowance, which is determined by the formula:
z min = Rz + T,
where Rz is the height of the irregularities obtained in the previous operation;
T – depth of the defective layer formed during the previous operation.
The values of Rz and T are determined from tables.
Column 14. For the closing links of dimensional chains, which are drawing dimensions, we write down the maximum values of these dimensions. We are not setting maximum allowance values yet.
Columns 15, 16. If the tolerance for the required operational size has a “–” sign, then in column 15 we put the number 1, if “+”, then in column 16 we put the number 2.
Column 17. We indicate approximately the values of the determined operational dimensions, use the equations of dimensional chains from column 11.
1. 9A8 = 8с9 = 12 mm;
2. 9A5 = 3с9 – 3с5 = 88 – 15 = 73 mm;
3. 9A3 = 3с9 = 88 mm;
4. 7A9 = 7z8 + 9A8 =0.2 + 12 = 12mm;
5. 7А12 = 3с12 +7А9 – 9А3 = 112 + 12 – 88 = 36 mm;
6. 10A7 = 7A9 + 9z10 = 12 + 0.2 = 12 mm;
7. 10A4 = 10A7 – 7A9 + 9A5 + 4z5 = 12 – 12 + 73 + 0.2 = 73 mm;
8. 10A2 = 10A7 – 7A9 + 9A3 + 2z3 = 12 – 12 + 88 + 0.2 = 88 mm;
9. 6A10 = 10A7 + 6z7 = 12 + 0.2 = 12 mm;
10. 6A13 = 6A10 – 10A7 + 7A12 + 12z13 = 12 – 12 + 36 + 0.2 = 36 mm;
11. 1A6 = 10A2 – 6A10 + 1z2 = 88 – 12 + 0.5 = 77 mm;
12. 1A11 = 10z11 + 1A6 + 6A10 = 0.2 + 77 + 12 = 89 mm;
13. 1A14 = 13z14 + 1A6 + 6A13 = 0.5 + 77 + 36 = 114 mm.
Column 18. We enter the tolerance values accepted according to accuracy table 7 for operational dimensions, taking into account the recommendations set out in. After entering the tolerances in column 18, you can determine the maximum values of the allowances and enter them in column 14.
The value of ∆z is determined from the equations in column 11 as the sum of the tolerances on the operational dimensions that make up the dimensional chain.
Column 19. In this column you need to enter the nominal values of the operating dimensions.
The essence of the method for calculating the nominal values of operational dimensions comes down to solving the dimensional chain equations written in column 11.
1. 8с9 = 9А89А8 =
2. 3с9 = 9А39А3 =
3. 3с5 = 3с9 – 9А5
9А5 = 3с9 – 3с5 = 
We accept: 9A5 = 73 -0.74
3с5 = 
4. 9z10 = 10A7 – 7A9
10A7 = 7A9 + 9z10 = 
We accept: 10A7 = 13.5 -0.43 (adjustment + 0.17)
9z10 = 
5. 4z5 = 10A4 – 10A7 + 7A9 – 9A5
10A4 = 10A7 – 7A9 + 9A5 + 4z5 = 
We accept: 10A4 = 76.2 -0.74 (adjustment + 0.17)
4z5 = 
6. 2z3 = 10A2 – 10A7 + 7A9 – 9A3
10A2 = 10A7 – 7A9 + 9A3 + 2z3 = 
We accept: 10A2 = 91.2 -0.87 (adjustment + 0.04)
2z3 = 
7. 7z8 = 7A9 – 9A8
7A9 = 7z8 + 9A8 = 
We accept: 7A9 = 12.7 -0.43 (adjustment: + 0.07)
7z8 = 
8. 3с12 = 7А12 – 7А9 + 9A3
7А12 = 3с12 +7А9 – 9А3 = 
We accept: 7A12 = 36.7 -0.62
3с12= 
9. 6z7 = 6A10 – 10A7
6A10 = 10A7 + 6z7 = 
We accept: 6A10 = 14.5 -0.43 (adjustment + 0.07)
6z7 = 
10. 12z13 = 6A13 – 6A10 + 10A7– 7A12
6A13 = 6A10 – 10A7 + 7A12 + 12z13 = 
We accept: 6A13 = 39.9 -0.62 (adjustment + 0.09)
12z13 = 
11. 1z2 = 6A10 – 10A2 + 1A6
1A6 = 10A2 – 6A10 + 1z2 = 
We accept: 1A6 = 78.4 -0.74 (adjustment + 0.03)
1z2 = 
12. 13z14 = 1A14 – 1A6 – 6A13
1A14 = 13z14 + 1A6 + 6A13 = 
We accept: 1A14 = 119.7 -0.87 (adjustment + 0.03)
13z14 = 
13. 10z11 = 1A11 – 1A6 – 6A10
1A11 = 10z11 + 1A6 + 6A10 = 
We accept: 1A11 = 94.3 -0.87 (adjustment + 0.03)
10z11 = 
After calculating the nominal values of the dimensions, we enter them in column 19 of the base selection card and, with processing allowances, write them down in the “note” column of the Processing Scheme (Figure 1.5).
After we fill out column 20 and the “approx.” column, we apply the obtained values of operational dimensions with tolerances to the sketches of the route technological process. This completes the calculation of the nominal values of long operational dimensions.
| Map for selecting bases and calculating operating sizes | ||||||||||||||||||
| Closing links | Operation No. | Operation name | Model equipment |
processing |
Operating |
Bases | Equations of dimensional chains |
Closing links of dimensional chains | Operating Dimensions | |||||||||
| Processed surfaces | Thermal depth layer | Selected from the conditions of measurement convenience | Technological options bases | Accepted technical no. and measure. bases | Designation | Limit dimensions | Tolerance mark and approx. operating value |
Magnitude |
Nominal meaning |
|||||||||
| min | max | |||||||||||||||||
|
magnitude |
||||||||||||||||||
| 5 | Will prepare. | GCM |
|
13z14=1A14–1A–6A13 10z11=1A11–1A6-6A10 1z2=6A10–10A2+1A6 |
||||||||||||||
| 10 | Turning | 1P365 |  |
6 | 6 | 12z13=6A13–6A10+10A7–7A12 |
||||||||||||
Figure 1.9 Map for selecting bases and calculating operating sizes
Calculation of operational dimensions with double-sided allowance
When processing surfaces with a double-sided allowance, it is advisable to calculate the operational dimensions using a statistical method for determining the value of the operational allowance depending on the chosen processing method and the size of the surfaces.
To determine the value of the operational allowance using the static method, depending on the processing method, we will use source tables.
To calculate operational dimensions with a double-sided allowance, for such surfaces we draw up the following calculation scheme:
Figure 1.10 Layout of operating allowances
Drawing up a sheet for calculating diametrical operating dimensions.
Column 1: Indicates the numbers of operations according to the developed technology in which this surface is processed.
Column 2: The processing method is indicated in accordance with the operational card.
Columns 3 and 4: The designation and value of the nominal diametrical operating allowance, adopted according to the tables in accordance with the processing method and dimensions of the workpiece, is indicated.
Column 5: The designation of the operating size is indicated.
Column 6: According to the accepted processing scheme, equations are drawn up to calculate operating dimensions.
Filling out the statement begins with the final operation.
Column 7: The accepted operating size with tolerance is indicated. The calculated value of the required operating size is determined by solving the equation from column 6.
Sheet for calculating operational dimensions when processing the outer diameter of the Ø20k6 (Ø20) axle
Name operations |
Operational allowance | Operating size | ||||
| Designation | Magnitude | Designation | Calculation formulas | Approximate size | ||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Zag | Stamping | Ø24 | ||||
| 10 | Turning (roughing) | D10 | D10=D20+2z20 | |||
| 20 | Turning (finishing) | Z20 | 0,4 | D20 | D20=D45+2z45 | |
| 45 | Grinding | Z45 | 0,06 | D45 | D45=damn rr | |
Sheet for calculating operational dimensions when processing the outer diameter of an axis Ø75 -0.12
| 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Zag | Stamping | Ø79 | ||||
| 10 | Turning (roughing) | D10 | D10=D20+2z20 | Ø75.8 –0.2 | ||
| 20 | Turning (finishing) | Z20 | 0,4 | D20 | D20=damn. rr |
Sheet for calculating operational dimensions when processing the outer diameter of the Ø30k6 (Ø30) axle
Sheet for calculating operational dimensions when processing the outer diameter of the shaft Ø20h7 (Ø20 -0.021)
| 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Zag | Stamping | Ø34 | ||||
| 15 | Turning (roughing) | D15 | D15=D25+2z25 | Ø20.8 –0.2 | ||
| 25 | Turning (finishing) | Z25 | 0,4 | D25 | D25=damn rr | Ø20 -0.021 |
Sheet for calculating operational dimensions when processing holes Ø8Н7 (Ø8 +0.015)
Sheet for calculating operational dimensions when processing holes Ø12 +0.07
Sheet for calculating operational dimensions when processing holes Ø14 +0.07
Sheet for calculating operational dimensions when processing holes Ø9 +0.058
After calculating the diametrical operating dimensions, we will plot their values on the sketches of the corresponding operations of the route description of the technological process.
1.9 Calculation of cutting conditions
When assigning cutting modes, the nature of the processing, the type and size of the tool, the material of its cutting part, the material and condition of the workpiece, the type and condition of the equipment are taken into account.
When calculating cutting conditions, the depth of cut, minute feed, and cutting speed are set. Let us give an example of calculating cutting conditions for two operations. For other operations, cutting modes are assigned according to vol. 2, p. 265-303.
010. Rough turning (Ø24)
Mill model 1P365, processed material – steel 45, tool material ST 25.
The cutter is equipped with a carbide plate ST 25 (Al 2 O 3 +TiCN+T15K6+TiN). The use of a carbide insert, which does not require regrinding, reduces the time required to change tools; in addition, the basis of this material is improved T15K6, which significantly increases the wear resistance and temperature resistance of ST 25.
Geometry of the cutting part.
All parameters of the cutting part are selected from the source Passing cutter: α = 8°, γ = 10°, β = +3º, f = 45°, f 1 = 5°.
2. Coolant grade: 5% emulsion.
3. The cutting depth corresponds to the amount of allowance, since the allowance is removed in one step.
4. The calculated feed is determined based on the roughness requirements (p. 266) and is specified according to the machine passport.
S = 0.5 rpm.
5. Fortitude, p.268.
6. The design cutting speed is determined from the specified tool life, feed and depth of cut from page 265.
where C v, x, m, y – coefficients [5], page 269;
T – tool life, min;
S – feed, rpm;
t – cutting depth, mm;
К v – coefficient taking into account the influence of the workpiece material.
K v = K m v ∙K p v ∙K and v,
K m v – coefficient that takes into account the influence of the properties of the material being processed on the cutting speed;
Кп v = 0.8 – coefficient taking into account the influence of the state of the workpiece surface on the cutting speed;
K and v = 1 – coefficient that takes into account the influence of the tool material on the cutting speed.
K m v = K g ∙,
where K g is a coefficient characterizing the steel group according to machinability.
K m v = 1∙
K v = 1.25 ∙0.8 ∙1 = 1,
7. Estimated rotation speed.
where D is the processed diameter of the part, mm;
V Р – design cutting speed, m/min.
According to the machine passport we take n = 1500 rpm.
8. Actual cutting speed.
where D is the processed diameter of the part, mm;
n – rotation speed, rpm.
9. The tangential component of the cutting force Pz, H is determined using the source formula, p. 271.
Р Z = 10∙С р ∙t x ∙S у ∙V n ∙К р,
where Р Z – cutting force, N;
C p, x, y, n – coefficients, p. 273;
S – feed, mm/rev;
t – cutting depth, mm;
V – cutting speed, rpm;
K r – correction factor (K r = K mr ∙K j r ∙K g r ∙K l r, – numerical values of these coefficients from, pp. 264, 275).
K p = 0.846∙1∙1.1∙0.87 = 0.8096.
P Z = 10∙300∙2.8∙0.5 0.75∙113 -0.15∙0.8096 = 1990 N.
10. Power from ,p.271.
,
where Р Z – cutting force, N;
V – cutting speed, rpm.
.
The power of the electric motor of the 1P365 machine is 14 kW, so the drive power of the machine is sufficient:
N res.< N ст.
3.67 kW<14 кВт.
035. Drilling
Drilling a hole Ø8 mm.
Machine model 2550F2, processed material – steel 45, tool material R6M5. Processing is carried out in one pass.
1. Justification of the grade of material and geometry of the cutting part.
Material of the cutting part of the tool is R6M5.
Hardness 63…65 HRCе,
Ultimate bending strength s p = 3.0 GPa,
Tensile strength s in = 2.0 GPa,
Ultimate compressive strength s compress = 3.8 GPa,
Geometry of the cutting part: w =10° – angle of inclination of the screw tooth;
f = 58° - main angle,
a = 8° - rear sharpening angle.
2. Depth of cut
t = 0.5∙D = 0.5∙8 =4 mm.
3. The calculated feed is determined based on the roughness requirements .с 266 and is specified according to the machine passport.
S = 0.15 rpm.
4. Durability p. 270.
5. The design cutting speed is determined from the specified tool life, feed and depth of cut.
where C v, x, m, y are coefficients, p.278.
T – tool life, min.
S – feed, rpm.
t – cutting depth, mm.
K V is a coefficient that takes into account the influence of the workpiece material, surface condition, tool material, etc.
6. Estimated rotation speed.
where D is the processed diameter of the part, mm.
V r – design cutting speed, m/min.
According to the machine passport we take n = 1000 rpm.
7. Actual cutting speed.
where D is the processed diameter of the part, mm.
n - rotation speed, rpm.
.
8. Torque
M cr = 10∙С M ∙ D q ∙ S y ∙K r.
S – feed, mm/rev.
D – drilling diameter, mm.
M cr = 10∙0.0345∙ 8 2 ∙ 0.15 0.8 ∙0.92 = 4.45 N∙m.
9. Axial force P o, N po , s. 277;
Р o = 10∙С Р ·D q ·S y ·К Р,
where С Р, q, у, K р, are coefficients p.281.
P o = 10∙68 8 1 0.15 0.7 0.92 = 1326 N.
9. Cutting power.
where M cr - torque, N∙m.
V – cutting speed, rpm.
0.46 kW< 7 кВт. Мощность станка достаточна для заданных условий обработки.
040. Grinding
Machine model 3T160, processed material – steel 45, tool material – normal electrocorundum 14A.
Plunge grinding with the periphery of the wheel.
1. Brand of material, geometry of the cutting part.
Select a circle:
PP 600×80×305 24A 25 N SM1 7 K5A 35 m/s. GOST 2424-83.
2. Depth of cut
3. Radial feed S р, mm/rev is determined by the formula from the source, p. 301, tab. 55.
S Р = 0.005 mm/rev.
4. The speed of the circle V K, m/s is determined by the formula from the source, page 79:
where D K is the diameter of the circle, mm;
D K = 300 mm;
n K = 1250 rpm – rotation speed of the grinding spindle.
5. The estimated rotation speed of the workpiece n s.r.r.p.m. will be determined using the formula from the source, p. 79.
where V Z.R – selected workpiece speed, m/min;
V Z.R will be determined from the table. 55, p. 301. Let's take V Z.P = 40 m/min;
d W – workpiece diameter, mm;
6. Effective power N, kW will be determined according to the recommendation in
source page 300:
for plunge-cut grinding with the periphery of a wheel
where the coefficient C N and the exponents r, y, q, z are given in Table. 56, p. 302;
V Z.R – workpiece speed, m/min;
S P – radial feed, mm/rev;
d W – workpiece diameter, mm;
b – grinding width, mm is equal to the length of the workpiece section to be ground;
The power of the electric motor of the 3T160 machine is 17 kW, so the drive power of the machine is sufficient:
N cut< N шп
1.55 kW< 17 кВт.
1.10 Rationing of operations
Calculation and technological time standards are determined by calculation.
There is a standard for piece time T SHT and a standard for calculating time. The calculation rate is determined by the formula on page 46:
where T pcs – standard piece time, min;
T p.z. – preparatory and final time, min;
n - number of parts in the batch, pcs.
T pcs = t main + t aux + t serv + t per,
where t main – main technological time, min;
tvsp – auxiliary time, min;
t obsl – workplace servicing time, min;
t lane – time of breaks and rest, min.
The main technological time for turning and drilling operations is determined by the formula on page 47:
where L is the estimated processing length, mm;
Number of passes;
S min – minute tool feed;
a is the number of simultaneously processed parts.
The estimated processing length is determined by the formula:
L = L res + l 1 + l 2 + l 3.
where L cut – cutting length, mm;
l 1 – tool lead length, mm;
l 2 – tool penetration length, mm;
l 3 – tool overtravel length, mm.
The service time for a workplace is determined by the formula:
t inspection = t technical inspection + t organizational inspection,
wheret technical maintenance – maintenance time, min;
t org.obsl – time of organizational servicing, min.
,
,
where is the coefficient determined according to the standards. We accept.
The time for break and rest is determined by the formula:
,
where is the coefficient determined according to the standards. We accept.
We present the calculation of time standards for three different operations
010 Turning
Let us first determine the estimated processing length. l 1, l 2, l 3 will be determined according to the data in Tables 3.31 and 3.32 on page 85.
L = 12 + 6 +2 = 20 mm.
Minute feed
S min = S rev ∙n, mm/min,
where S rev – reverse feed, mm/rev;
n – number of revolutions, rpm.
S min = 0.5∙1500 = 750 mm/min.
min.
Auxiliary time consists of three components: for installation and removal of a part, for transition, and for measurement. This time is determined by cards 51, 60, 64 on pages 132, 150, 160 by:
t set/removed = 1.2 min;
t transition = 0.03 min;
tmeas = 0.12 min;
tvsp = 1.2 + 0.03 + 0.12 = 1.35 min.
Maintenance time
min.
Organizational service time
min.
Break times
min.
Standard piece time per operation:
T pcs = 0.03 + 1.35 + 0.09+ 0.07 = 1.48 min.
035 Drilling
Drilling a hole Ø8 mm.
Let's determine the estimated processing length.
L = 12 + 10.5 + 5.5 = 28 mm.
Minute feed
S min = 0.15∙800 = 120 mm/min.
Main technological time:
min.
Processing is carried out on a CNC machine. Cycle time automatic operation machine according to the program is determined by the formula:
T c.a = T o + T mv, min,
where T o is the main time of automatic operation of the machine, T o = t main;
T mv – machine-auxiliary time.
T mv = T mv.i + T mv.x, min,
where T mv.i is machine-auxiliary time for automatic tool change, min;
T mv.x – machine-auxiliary time for performing automatic auxiliary moves, min.
T mv.i is determined according to Appendix 47, .
We accept T mv.x = T o /20 = 0.0115 min.
T c.a = 0.23 + 0.05 + 0.0115 = 0.2915 min.
The rate of piece time is determined by the formula:
where T in – auxiliary time, min. Determined by map 7, ;
a tech, a org, a exc – time for maintenance and rest, determined by , map 16: a tech + a org + a exc = 8%;
T in = 0.49 min.
040. Grinding
Definition of basic (technological) time:
where l is the length of the processed part;
l 1 – the amount of infeed and overtravel of the tool according to the map 43, ;
i – number of passes;
S – tool feed, mm.
min
Definition of auxiliary time, see card 44,
T in =0.14+0.1+0.06+0.03=0.33 min
Determining time for workplace maintenance, rest and natural needs:
,
where a obs and a dept are the time for servicing the workplace, rest and natural needs as a percentage of the operational time according to the card 50, :
a obs = 2% and a otd = 4%.
Determination of the norm of piece time:
T w = T o + T v + T obs + T dept = 3.52 + 0.33 + 0.231 = 4.081 min
1.11 Economic comparison of 2 operation options
When developing a technological process for machining, the task arises of choosing from several processing options the one that provides the most economical solution. Modern methods of mechanical processing and a wide variety of machine tools make it possible to create various technology options that ensure the production of products that fully meet all the requirements of the drawing.
In accordance with the provisions for assessing the economic efficiency of new technology, the most profitable option is the one for which the sum of current and reduced capital costs per unit of production is minimal. The components of the sum of the given costs should include only those costs that change their value when switching to a new version of the technological process.
The sum of these costs, related to the operating hours of the machine, can be called hourly present costs.
Consider the following two options for performing a turning operation, in which processing is carried out on different machines:
1. according to the first option, rough turning of the outer surfaces of the part is carried out on a universal screw-cutting lathe, model 1K62;
2. According to the second option, rough turning of the outer surfaces of the part is carried out on a turret lathe model 1P365.
1. Operation 10 is performed on a 1K62 machine.
The value characterizes the efficiency of the equipment. A lower value for comparing machines with equal productivity indicates that the machine is more economical.
Value of hourly reduced costs
where - the basic and additional wages, as well as social security accruals for the operator and service technician for the physical hour of work of the machines being serviced, kopecks/hour;
The multi-machine coefficient, taken according to the actual state in the area under consideration, is assumed to be M = 1;
Hourly costs for operating the workplace, kopecks/hour;
Standard coefficient of economic efficiency of capital investments: for mechanical engineering = 2;
Specific hourly capital investments in the machine, kopecks/hour;
Specific hourly capital investments in the building, kopecks/hour.
The basic and additional wages, as well as social security contributions for the operator and service technician, can be determined using the formula:
, kop/h,
where is the hourly tariff rate of a machine operator of the corresponding category, kopecks/hour;
1.53 – total coefficient, representing the product of the following partial coefficients:
1.3 – coefficient of compliance with standards;
1.09 – additional salary coefficient;
1.077 – coefficient of social security contributions;
k – coefficient taking into account the salary of the adjuster, we take k = 1.15.
The amount of hourly costs for operating the workplace in the event of a decrease
The machine load must be adjusted using the coefficient if the machine cannot be reloaded. In this case, the adjusted hourly cost is:
, kop/h,
where is the hourly cost of operating the workplace, kopecks/hour;
Correction factor:
,
The share of semi-fixed costs in hourly costs at the workplace, we accept;
Machine load factor.
where Т ШТ – piece time per operation, Т ШТ = 2.54 min;
t B – exhaust stroke, take t B = 17.7 min;
m P – accepted number of machines per operation, m P = 1.
;
,
where is the practical adjusted hourly costs at the base workplace, kopecks;
Machine coefficient, showing how many times the costs associated with the operation of a given machine are greater than the similar costs of the base machine. We accept.
kop/hour
The capital investment for the machine and the building can be determined by:
where C is the book value of the machine, we take C = 2200.
, kop/h,
Where F is the production area occupied by the machine, taking into account passes:
where is the production area occupied by the machine, m2;
Coefficient taking into account additional production area, .
kop/hour
kop/hour
Cost of machining for the operation in question:
, cop.
cop.
2. Operation 10 is performed on a 1P365 machine.
C = 3800 rub.
T SHT = 1.48 min.
kop/hour
kop/hour
kop/hour
cop.
Having compared the options for performing a turning operation on various machines, we come to the conclusion that turning the outer surfaces of the part should be done on a turret lathe model 1P365. Since the cost of machining a part is lower than if it is performed on a machine model 1K62.
2. Design of special machine tools
2.1 Initial data for designing machine tools
In this course project, a machine tool has been developed for operation No. 35, in which drilling, countersinking and reaming of holes are carried out using a CNC machine.
The type of production, the production program, as well as the time spent on the operation, which determine the level of speed of the device when installing and removing the part, influenced the decision to mechanize the device (the part is clamped in ticks using a pneumatic cylinder).
The device is used to install only one part.
Let's look at the layout of the part in the fixture:
Figure 2.1 Scheme of installing a part in a vice
1, 2, 3 – mounting base – deprives the workpiece of three degrees of freedom: movement along the OX axis and rotation around the OZ and OY axes; 4, 5 – double support base – deprives two degrees of freedom: movement along the OY and OZ axes; 6 – support base – prevents rotation around the OX axis.
2.2 Schematic diagram of the machine tool
As a machine tool we will use a machine vice equipped with a pneumatic drive. The pneumatic drive ensures a constant clamping force on the part, as well as quick fastening and detachment of the workpiece.
2.3 Description of design and operating principle
A universal self-centering vice with two movable, replaceable jaws is designed for securing axle-type parts when drilling, countersinking and reaming holes. Let's consider the design and operating principle of the device.
At the left end of the body 1 of the vice there is an adapter sleeve 2, and on it a pneumatic chamber 3. A diaphragm 4 is clamped between the two covers of the pneumatic chamber, which is rigidly fixed to a steel disk 5, in turn, fixed to a rod 6. The rod 6 of the pneumatic chamber 3 is connected through a rod 7 with a rolling pin 8, at the right end of which there is a rack 9. The rack 9 is in mesh with a gear wheel 10, and a gear wheel 10 is in mesh with an upper movable rack 11, on which the right movable jaw is installed and secured with two pins 23 and two bolts 17 12. The lower end of the pin 14 enters the ring groove at the left end of the rolling pin 8, its upper end is pressed into the hole of the left movable jaw 13. Replaceable clamping prisms 15, corresponding to the diameter of the axis being processed, are secured with screws 19 on the movable jaws 12 and 13. The pneumatic chamber 3 is attached to adapter sleeve 2 using 4 bolts 18. In turn, adapter sleeve 2 is attached to the body of fixture 1 using bolts 16.
When compressed air enters the left cavity of the pneumatic chamber 3, the diaphragm 4 bends and moves the rod 6, rod 7 and rolling pin 8 to the right. The rolling pin 8 with its finger 14 moves the sponge 13 to the right, and with its left rack end, rotating the gear 10, moves the upper rack 11 with the sponge 12 to the left. Thus, jaws 12 and 13, moving, clamp the workpiece. When compressed air enters the right cavity of the pneumatic chamber 3, the diaphragm 4 bends in the other direction and the rod 6, rod 7 and rolling pin 8 are moved to the left; rolling pin 8 spreads jaws 12 and 13 with prisms 15.
2.4 Calculation of machine fixtures
Power calculation of the device
Figure 2.2 Scheme for determining workpiece clamping forces
To determine the clamping force, let us depict the workpiece in a simplified manner in the fixture and depict the moments from the cutting forces and the required required clamping force.
In Figure 2.2:
M – torque on the drill;
W – required fastening force;
α – prism angle.
The required force for securing the workpiece is determined by the formula:
, N,
where M is the torque on the drill;
α – prism angle, α = 90;
The coefficient of friction on the working surfaces of the prism is taken to be ;
D – workpiece diameter, D = 75 mm;
K – safety factor.
K = k 0 ∙k 1 ∙k 2 ∙k 3 ∙k 4 ∙k 5 ∙k 6 ,
where k 0 is the guaranteed safety factor, for all processing cases k 0 = 1.5
k 1 – coefficient that takes into account the presence of random irregularities on the workpieces, which entails an increase in cutting forces, we take k 1 = 1;
k 2 – coefficient taking into account the increase in cutting forces from the progressive dulling of the cutting tool, k 2 = 1.2;
k 3 – coefficient taking into account the increase in cutting forces during intermittent cutting, k 3 = 1.1;
k 4 – coefficient taking into account the variability of the clamping force when using pneumatic lever systems, k 4 = 1;
k 5 – coefficient taking into account the ergonomics of manual clamping elements, we take k 5 = 1;
k 6 is a coefficient that takes into account the presence of moments tending to rotate the workpiece, we take k 6 =1.
K = 1.5∙1∙1.2∙1.1∙1∙1∙1 = 1.98.
Torque
М= 10∙С М ∙ D q ∙ S у ∙К р.
where С М, q, у, K р, are coefficients, p.281.
S – feed, mm/rev.
D – drilling diameter, mm.
M = 10∙0.0345∙ 8 2 ∙ 0.15 0.8 ∙0.92 = 4.45 N∙m.
N.
Let us determine the force Q on the rod of the diaphragm pneumatic chamber. The force on the rod changes as it moves, since at a certain point in the movement the diaphragm begins to exert resistance. The rational stroke length of the rod, at which there is no sharp change in force Q, depends on the design diameter D, thickness t, material and design of the diaphragm, as well as on the diameter d of the support disk.
In our case, we take the diameter of the working part of the diaphragm D = 125 mm, the diameter of the support disk d = 0.7∙D = 87.5 mm, the diaphragm is made of rubberized fabric, the thickness of the diaphragm is t = 3 mm.
Force in the initial position of the rod:
, N,
Where p is the pressure in the pneumatic chamber, we take p = 0.4∙10 6 Pa.
Force on the rod when moving by 0.3D:
, N.
Calculation of devices for accuracy
Based on the accuracy of the maintained size of the workpiece, the following requirements are imposed on the corresponding dimensions of the device.
When calculating the accuracy of fixtures, the total error when processing a part should not exceed the tolerance value T of the size, i.e.
The total error of the device is calculated using the following formula:
where T is the tolerance of the size being performed;
Positioning error, since in this case there is no deviation of the actually achieved position of the part from the required one;
Fastening error, ;
Error in installing the fixture on the machine, ;
Error in the position of the part due to wear of the fixture elements;
The approximate wear of installation elements can be determined by the formula:
,
where U 0 – average wear of installation elements, U 0 = 115 µm;
k 1 , k 2 , k 3 , k 4 – respectively, coefficients that take into account the influence of the workpiece material, equipment, processing conditions and the number of workpiece installations.
k1 = 0.97; k2 = 1.25; k3 = 0.94; k 4 = 1;
We accept microns;
Error from skew or displacement of the tool, since there are no guide elements in the device;
A coefficient that takes into account the deviation of the scattering of the values of the component quantities from the law of normal distribution,
Coefficient that takes into account the reduction in the limit value of the positioning error when working on configured machines,
A coefficient that takes into account the share of processing error in the total error caused by factors independent of the device,
Economic processing accuracy = 90 microns.
3. Design of special testing equipment
3.1 Initial data for designing a control device
Testing and measuring devices are used to check the compliance of the parameters of the manufactured part with the requirements of the technological documentation. Preference is given to devices that make it possible to determine the spatial deviation of some surfaces in relation to others. This device meets these requirements, because. measures radial runout. The device has a simple design, is easy to use and does not require highly qualified controllers.
Axle-type parts in most cases transmit significant torques to mechanisms. In order for them to work flawlessly for a long time, high precision in the execution of the main working surfaces of the axle in diametrical dimensions is of great importance.
The inspection process primarily involves a continuous check of the radial runout of the outer surfaces of the axle, which can be carried out using a multi-dimensional inspection device.
3.2 Schematic diagram of the machine tool
Figure 3.1 Schematic diagram of the control device
Figure 3.1 shows a schematic diagram of a device for controlling radial runout of the outer surfaces of an axle part. The diagram shows the main parts of the device:
1 – device body;
2 – front headstock;
3 – tailstock;
4 – stand;
5 – indicator heads;
6 – controlled part.
3.3 Description of design and operating principle
On the body 1, with the help of screws 13 and washers 26, a headstock 2 with a mandrel 20 and a tailstock 3 with a fixed return center 23 are fixed, on which the axle under test is installed. The axial position of the axis is fixed by a fixed return center 23. The axis is pressed against the latter by a spring 21, which is located in the central axial hole of the quill 5 and acts on the adapter 6. The quill 5 is mounted in the headstock 2 with the ability to rotate relative to the longitudinal axis thanks to bushings 4 at the left end In the quill 5, a handwheel 19 with a handle 22 is installed, which is secured by a washer 8 and a pin 28, the torque from the handwheel 19 is transmitted to the quill 5 using a key 27. To the adapter 6, the rotational movement during measurement is transmitted through a pin 29, which is pressed into the quill 5. In addition, , at the other end of the adapter 6, a mandrel 20 with a conical working surface is inserted for precise backlash-free alignment of the axis, since the latter has a cylindrical axial hole with a diameter of 12 mm. The taper of the mandrel depends on the tolerance T and the diameter of the axle hole and is determined by the formula:
mm.
In two racks 7, attached to the body 1 with screws 16 and washers 25, a shaft 9 is installed, along which the brackets 12 move and are fixed with screws 14. On the brackets 12, rolling pins 10 are installed using screws 14, on which are screws 15, nuts 17 and washers 24 assigned to IG 30.
Two IG 30 are used to check the radial runout of the outer surfaces of the axis, which is given one or two turns and the maximum readings of IG 30, which determine the runout, are counted. The device provides high productivity of the control process.
3.4 Calculation of the control device
The most important condition that control devices must satisfy is to ensure the necessary measurement accuracy. Accuracy largely depends on the measurement method adopted, on the degree of perfection of the circuit diagram and design of the device, as well as on the accuracy of its manufacture. An equally important factor influencing accuracy is the accuracy of the surface used as a measuring base for the parts being controlled.
where is the manufacturing error of the installation elements and their location on the device body, we take mm;
The error caused by the inaccuracy in the manufacture of transmission elements is taken as mm;
The systematic error, taking into account deviations of the installation dimensions from the nominal ones, is taken in mm;
Based error, we accept ;
The error in the displacement of the measuring base of the part from the specified position is taken as mm;
Fastening error, accept mm;
The error from the gaps between the axes of the levers is taken as ;
The error of deviation of installation elements from the correct geometric shape is taken as ;
The error of the measurement method is mm.
The total error can be up to 30% of the tolerance of the controlled parameter: 0.3∙T = 0.3∙0.1 = 0.03 mm.
0.03 mm ≥ 0.0034 mm.
3.5 Development of a setup chart for operation No. 30
The development of a setup map allows you to understand the essence of setting up a CNC machine when performing an operation with an automatic method of obtaining a given accuracy.
As adjustment dimensions we take the dimensions corresponding to the middle of the tolerance field of the operational size. The tolerance value for the adjustment size is accepted
T n = 0.2 * T op.
where Т n – tolerance on the adjusting size.
T op – tolerance for the operating size.
For example, in this operation we sharpen a surface Ø 32.5 -0.08, then the setting size will be equal to
32.5 – 32.42 = 32.46 mm.
T n = 0.2 * (-0.08) = - 0.016 mm.
Adjustment dimension Ø 32.46 -0.016.
The remaining dimensions are calculated in the same way.
Conclusions on the project
According to the assignment for the course project, a technological process for manufacturing the shaft was designed. The technological process contains 65 operations, for each of which cutting modes, time standards, equipment and accessories are indicated. For the drilling operation, a special machine tool has been designed to ensure the necessary precision in manufacturing the part, as well as the required clamping force.
When designing the technological process for manufacturing a shaft, a setup chart for turning operation No. 30 was developed, which allows you to understand the essence of setting up a CNC machine when performing an operation with an automatic method of obtaining a given accuracy.
During the implementation of the project, a calculation and explanatory note was drawn up, which describes in detail all the necessary calculations. Also, the settlement and explanatory note contains appendices, which include operational cards, as well as drawings.
References
1. Handbook of mechanical engineering technologist. In 2 volumes / ed. A.G. Kosilova and R.K. Meshcheryakov.-4th ed., revised. and additional – M.: Mechanical Engineering, 1986 – 496 p.
2. Granovsky G.I., Granovsky V.G. Cutting metals: Textbook for mechanical engineering. and instrumentation specialist. universities _ M.: Higher. school, 1985 – 304 p.
3. Marasinov M.A. Guide to calculating operating sizes. - Rybinsk. RGATA, 1971.
4. Marasinov M.A. Design of technological processes in mechanical engineering: Tutorial.- Yaroslavl. 1975.-196 p.
5. Mechanical engineering technology: Textbook for completing a course project / V.F. Bezyazychny, V.D. Korneev, Yu.P. Chistyakov, M.N. Averyanov. - Rybinsk: RGATA, 2001. - 72 p.
6. General machine-building standards for auxiliary, workplace maintenance and preparatory and final standards for technical standardization of machine tools. Serial production. M, Mechanical Engineering. 1964.
7. Anserov M.A. Accessories for metal-cutting machines. 4th edition, corrected. and additional L., Mechanical Engineering, 1975
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technological process design detail
1. Design part
1.1 Description of the assembly unit
1.2 Description of the design of parts included in the design of the unit
1.3 Description of modifications of designs proposed by the student
2. Technological part
2.1 Analysis of manufacturability of part design
2.2 Development of a route technological process for manufacturing a part
2.3 Selection of used technological equipment and tools
2.4 Development of basing schemes
1 . Design part
1 . 1 Description of the design of a unit or assembly unit
The adapter part, for which the manufacturing process will subsequently be designed, is an integral part of an assembly unit, such as a valve, which, in turn, is used in modern equipment (for example, an oil filter in a car). An oil filter is a device designed to clean engine oil from mechanical particles, resins and other impurities that pollute it during the operation of an internal combustion engine. This means that the lubrication system of internal combustion engines cannot do without an oil filter.
Figure 1. 1 - Valve BNTU 105081. 28.00 Sat
Parts: Spring (1), spool (2), adapter (3), tip (4), plug (5), washer 20 (6), ring (7), (8).
To assemble the “Valve” assembly, you must perform the following steps:
1. Before assembly, check the surfaces for cleanliness, as well as for the absence of abrasive substances and corrosion between the mating parts.
2. When installing, protect the rubber rings (8) from distortions, twisting, and mechanical damage.
3. When assembling the grooves for the rubber rings in the part (4), lubricate with Litol-24 grease GOST 21150-87.
4. Comply with tightening standards in accordance with OST 37.001.050-73, as well as technical requirements for tightening in accordance with OST 37.001.031-72.
5. The valve must be sealed when supplying oil to any cavity, with the second one plugged, with a viscosity of 10 to 25 cSt under a pressure of 15 MPa; the appearance of individual drops at the connection of the tip (4) with the adapter (3) is not a rejection sign.
6. Comply with other technical requirements in accordance with STB 1022-96.
1 . 2 Description of the part design, included in the design of the unit (assembly unit)
A spring is an elastic element designed to accumulate or absorb mechanical energy. The spring can be made of any material that has sufficiently high strength and elastic properties (steel, plastic, wood, plywood, even cardboard).
General-purpose steel springs are made from high-carbon steels (U9A-U12A, 65, 70) alloyed with manganese, silicon, vanadium (65G, 60S2A, 65S2VA). For springs operating in aggressive environments, stainless steel (12Х18Н10Т), beryllium bronze (BrB-2), silicon-manganese bronze (BrKMts3-1), tin-zinc bronze (BrOTs-4-3) are used. Small springs can be wound from ready-made wire, while powerful ones are made from annealed steel and are hardened after molding.
A washer is a fastener placed under another fastener to create a larger supporting surface area, reduce damage to the surface of the part, prevent the fastener from self-unscrewing, and also to seal the connection with the gasket.
Our design uses a washer GOST 22355-77
Spool, spool valve - a device that directs the flow of liquid or gas by displacing the moving part relative to the windows in the surface on which it slides.
Our design uses spool 4570-8607047
Spool material - Steel 40Х
An adapter is a device, device or part designed to connect devices that do not have another compatible connection method.
Figure 1. 2 Sketch of the “Adapter” part
Table 1. 1
Summary table of the surface characteristics of the part (adapter).
|
Name surfaces |
Accuracy (Quality) |
Roughness, |
Note |
|
|
End (flat) (1) |
End runout is no more than 0.1 relative to the axis. |
|||
|
External threaded (2) |
||||
|
Groove (3) |
||||
|
Internal cylindrical (4) |
||||
|
External cylindrical (5) |
Deviation from perpendicularity no more than 0.1 relative to (6) |
|||
|
End (flat) (6) |
||||
|
Internal threaded (7) |
||||
|
Internal cylindrical (9) |
||||
|
Groove (8) |
||||
|
Internal cylindrical (10) |
Table 1. 2
Chemical composition of steel Steel 35GOST 1050-88
The material that was chosen for the manufacture of the part in question is steel 35GOST 1050-88. Steel 35 GOST1050-88 is a high-quality structural carbon steel. It is used for parts of low strength that experience low stress: axles, cylinders, crankshafts, connecting rods, spindles, sprockets, rods, traverses, shafts, tires, disks and other parts.
1 . 3 ABOUTwriting modifications of designs proposed by the student
The adapter part complies with all accepted norms, state standards, design standards, and therefore does not require modifications and improvements since this will lead to an increase in the number of technological operations and equipment used, resulting in an increase in processing time, which will lead to an increase in the cost of a unit of production, which is not economically feasible.
2 . Technological part
2 . 1 Analysis of manufacturability of part design
The manufacturability of a part is understood as a set of properties that determine its adaptability to achieving optimal costs during production, operation and repair for given quality indicators, output volume and work performance. Analysis of the manufacturability of a part is one of the important stages in the development of a technological process and is carried out, as a rule, in two stages: qualitative and quantitative.
A qualitative analysis of the adapter part for manufacturability showed that it contains a sufficient number of sizes, types, tolerances, and roughness for its manufacture, that it is possible to bring the workpiece as close as possible to the dimensions and shape of the part, and the ability to process it with cutting tools. The material of the part is St35GOST 1050-88, it is widely available and widespread. The weight of the part is 0.38 kg, therefore there is no need to use additional equipment for its processing and transportation. All surfaces of the part are easily accessible for processing and their design and geometry allow processing with standard tools. All holes in the part are through, therefore there is no need to position the tool during processing.
All chamfers are made at the same angle, therefore, can be made with one tool, the same applies to grooves (groove cutter), the part contains 2 grooves for the tool to exit when cutting threads, this is a sign of manufacturability. The part is rigid, since the ratio of length to diameter is 2.8, and therefore does not require additional fixtures to secure it.
Due to the simplicity of the design, small dimensions, low weight and small number of machined surfaces, the part is quite technologically advanced and does not pose any difficulties for mechanical processing. I determine the manufacturability of a part using quantitative indicators that are necessary to determine the accuracy coefficient. The data obtained are shown in Table 2. 1.
Table 2. 1
Number and precision of surfaces
The manufacturability coefficient for accuracy is 0.91>0.75. This shows low requirements for the accuracy of the surfaces of the adapter part and indicates its manufacturability.
To determine roughness, all necessary data are summarized in table 2. 2.
Table 2. 2
Number and roughness of surfaces
The processability coefficient for roughness is 0.0165<0. 35, это свидетельствует о малых требованиях по шероховатости для данной детали, что говорит о её технологичности
Despite the presence of low-tech features, according to qualitative and quantitative analysis, the adapter part is generally considered technologically advanced.
2 .2 Development of a route technological process for manufacturing a part
To obtain the required shape of the part, trimming the ends “as clean” is used. We sharpen the surface Ш28. 4-0. 12 for a length of 50. 2-0, 12, maintaining R0. 4max. Next we sharpen the chamfer 2.5×30°. We sharpen the groove “B”, maintaining the dimensions: 1. 4+0, 14; angle 60°; Ш26. 5-0. 21; R0. 1; R1; 43+0. 1. Centers the end. Drill a hole Ш17 to a depth of 46. 2-0. 12. Boring hole Ш14 to Ш17. 6+0. 12 to depth 46. 2-0. 12. Boring Ш18. 95+0. 2 to depth 18. 2-0. 12. Boring the groove “D”, maintaining the dimensions. Boring chamfer 1. 2×30°. We cut the end to size 84. 2-0, 12. Drill hole Ш11 to the entrance to hole Ш17. 6+0. 12. Countersink chamfer 2.5×60° in hole Ш11. Sharpen Sh31. 8-0, 13 for length 19 for M33Ch2-6g thread. Grind chamfer 2.5×45°. Sharpen groove “B”. Cut the thread M33Ch2-6g. Grind the chamfer maintaining dimensions Ш46, angle 10°. Cut the thread M20Х1-6H. Drill hole Ш9 through. Countersink a chamfer of 0.3×45° in the Ш9 hole. Grind hole Ш18+0.043 to Ra0. 32. Grind Ш28. 1-0. 03 to Ra0. 32 with grinding the right end to size 84. Grind W to Ra0.16.
Table 2.4
List of mechanical operations
|
Operation No. |
Operation name |
|
|
CNC turning |
||
|
CNC turning |
||
|
Screw-cutting lathe. |
||
|
Vertical drilling |
||
|
Vertical drilling |
||
|
Internal grinding |
||
|
Cylindrical grinding |
||
|
Cylindrical grinding |
||
|
Lathe-screw-cutting |
||
|
Control by the performer |
2 .3 Selection of used technological equipment and tools
In modern production conditions, cutting tools, used when processing large batches of parts with the required accuracy, play an important role. In this case, indicators such as durability and the method of adjusting to size come first.
The choice of machines for the designed technological process is made after each operation has been previously developed. This means that the following are selected and determined: surface processing method, accuracy and roughness, cutting tool and type of production, overall dimensions of the workpiece.
The following equipment is used to manufacture this part:
1. CNC lathe ChPU16K20F3;
2. Screw-cutting lathe 16K20;
3. Vertical drilling machines 2N135;
4. Internal grinding machine 3K227V;
5. Semi-automatic cylindrical grinding machine 3M162.
CNC lathe 16K20T1
The CNC lathe model 16K20T1 is designed for fine machining of parts such as rotating bodies in a closed semi-automatic cycle.
Figure 2. 1 - CNC lathe 16K20T1
Table 2.5
Technical characteristics of the CNC lathe 16K20T1
|
Parameter |
Meaning |
|
|
The largest diameter of the workpiece being processed, mm: |
||
|
above the bed |
||
|
above the caliper |
||
|
Maximum length of workpiece processed, mm |
||
|
Height of centers, mm |
||
|
Maximum rod diameter, mm |
||
|
Cutting thread pitch: metric, mm; |
||
|
Spindle hole diameter, mm |
||
|
Morse spindle inner taper |
||
|
Spindle rotation speed, rpm. |
||
|
Feed, mm/rev. : |
||
|
Longitudinal |
||
|
Transverse |
||
|
Morse quill hole cone |
||
|
Cutter section, mm |
||
|
Chuck diameter (GOST 2675.80), mm |
||
|
Main motion drive electric motor power, kW |
||
|
Numerical control device |
||
|
Deviation from the flatness of the end surface of the sample, µm |
||
|
Machine dimensions, mm |
||
Figure 2. 2 - Screw-cutting lathe 16K20
The machines are designed to perform a variety of turning operations and for cutting threads: metric, modular, inch, pitch. The designation of the machine model 16K20 acquires additional indices:
“B1”, “B2”, etc. - when changing the main technical characteristics;
“U” - when the machine is equipped with an apron with a built-in accelerated movement motor and a feedbox, which provides the ability to cut threads of 11 and 19 threads per inch without replacing replaceable gears in the gearbox;
“C” - when the machine is equipped with a drilling and milling device designed to perform drilling, milling work and cutting threads at different angles on parts mounted on the machine support;
“B” - when ordering a machine with an increased largest diameter for processing the workpiece above the bed - 630 mm and a support - 420 mm;
“G” - when ordering a machine with a recess in the bed;
“D1” - when ordering a machine with an increased largest diameter of the rod passing through the hole in the spindle 89 mm;
“L” - when ordering a machine with a transverse movement dial division price of 0.02mm;
“M” - when ordering a machine with a mechanized drive of the upper part of the support;
“C” - when ordering a machine with a digital indexing device and linear displacement transducers;
“RC” - when ordering a machine with a digital indexing device and linear displacement converters and with stepless control of the spindle speed;
Table 2. 6
Technical characteristics of the screw-cutting lathe 16K20
|
Parameter name |
Meaning |
|
|
1 Indicators of the workpiece processed on the machine |
||
|
1. 1 Largest diameter of the workpiece being processed: above the bed, mm |
||
|
1. 2 Largest diameter of the workpiece above the support, mm, not less |
||
|
1. 3 Maximum length of the installed workpiece (when installed in the centers), mm, not less above the recess in the frame, mm, not less |
||
|
1. 4 Height of centers above frame guides, mm |
||
|
2 Indicators of the tool installed on the machine |
||
|
2. 1 Maximum height of the cutter installed in the tool holder, mm |
||
|
3 Indicators of the main and auxiliary movements of the machine |
||
|
3. 1 Number of spindle speeds: direct rotation reverse rotation |
||
|
3. 2 Spindle frequency limits, rpm |
||
|
3. 3 Number of caliper feeds longitudinal transverse |
||
|
3. 4 Caliper feed limits, mm/rev longitudinal transverse |
||
|
3. 5 Limits of pitches of cut threads metric, mm modular, module inch, number of threads pitch, pitch |
||
|
3. 6 Speed of rapid movements of the caliper, m/min: longitudinal transverse |
||
|
4 Indicators of the power characteristics of the machine |
||
|
4. 1 Maximum torque on the spindle, kNm |
||
|
4. 2 |
||
|
4. 3 Fast motion drive power, kW |
||
|
4. 4 Cooling drive power, kW |
||
|
4. 5 Total power installed on the machine electric motors, kW |
||
|
4. 6 Total power consumption of the machine, (maximum), kW |
||
|
5 Dimensions and weight of the machine |
||
|
5. 1 Overall dimensions of the machine, mm, no more: |
||
|
5. 2 Machine weight, kg, no more |
||
|
6 Characteristics of electrical equipment |
||
|
6. 1 Type of supply current |
AC, three-phase |
|
|
6. 2 Current frequency, Hz |
||
|
7 Corrected sound power level, dBa |
||
|
8 Machine accuracy class according to GOST 8 |
Figure 2. 3 - Vertical drilling machine 2T150
The machine is designed for: drilling, reaming, countersinking, reaming and threading. A vertical drilling machine with a table moving along a round column and a table rotating on it. The machine can process small parts on a table, and larger parts on a base plate. Manual and mechanical spindle feed. Adjustment of processing depth with automatic feed cut-off. Thread cutting with manual and automatic spindle reversal at a given depth. Processing small parts on the table. Control of spindle movement along the ruler. Built-in cooling.
Table 2. 7
Technical characteristics of the machine Vertical drilling machine 2T150
|
Largest nominal drilling diameter, mm cast iron SCh20 |
||
|
The largest diameter of the cut thread, mm, in steel |
||
|
Hole accuracy after reaming |
||
|
Spindle taper |
Morse 5 AT6 |
|
|
Maximum spindle movement, mm |
||
|
Distance from the end of the spindle to the table, mm |
||
|
Maximum distance from the end of the spindle to the plate, mm |
||
|
Maximum table movement, mm |
||
|
Working surface size, mm |
||
|
Number of spindle speeds |
||
|
Spindle speed limits, rpm. |
||
|
Number of spindle feeds |
||
|
Spindle feed rate, mm/rev. |
||
|
Maximum torque on the spindle, Nm |
||
|
Maximum feed force, N |
||
|
Angle of rotation of the table around the column |
||
|
Cutting off the feed when reaching the specified drilling depth |
automatic |
|
|
Type of supply current |
Three-phase alternating |
|
|
Voltage, V |
||
|
Main drive drive power, kW |
||
|
Total electric motor power, kW |
||
|
Overall dimensions of the machine (LxBxH), mm, no more |
||
|
Machine weight (net/gross), kg, no more |
||
|
Overall dimensions of packaging (LxBxH), mm, no more |
Figure 2. 4 - Internal grinding machine 3K228A
The internal grinding machine 3K228A is designed for grinding cylindrical and conical, blind and through holes. The 3K228A machine has a wide range of rotation speeds for grinding wheels, the product spindle, cross feed values and table movement speeds, ensuring the processing of parts at optimal conditions.
Roller guides for the transverse movement of the grinding head, together with the final link - a ball screw pair, ensure minimal movements with high accuracy. A device for grinding the ends of products allows you to process holes and an end on a 3K228A machine in one installation of the product.
Accelerated setup transverse movement of the grinding head reduces auxiliary time when readjusting the 3K228A machine.
To reduce the heating of the bed and eliminate the transmission of vibration to the machine, the hydraulic drive is installed separately from the machine and connected to it with a flexible hose.
The magnetic separator and conveyor filter provide high quality cleaning of the coolant, which improves the quality of the treated surface.
Automatic termination of cross feed after removing the set allowance allows the operator to simultaneously control several machines.
Table 2.8
Technical characteristics of the internal grinding machine 3K228A
|
Characteristic |
||
|
The largest diameter of the grinded hole, mm |
||
|
Maximum grinding length with the largest diameter of the grinding hole, mm |
||
|
The largest outer diameter of the installed product without casing, mm |
||
|
The largest angle of the grinded cone, degrees. |
||
|
Distance from the axis of the product spindle to the table mirror, mm |
||
|
The greatest distance from the end of the new wheel of the face grinding device to the supporting end of the product spindle, mm |
||
|
Main drive drive power, kW |
||
|
Total power of electric motors, kW |
||
|
Machine dimensions: length*width*height, mm |
||
|
Total floor area of the machine with remote equipment, m2 |
||
|
Weight 3K228A, kg |
||
|
Product sample processing accuracy indicator: |
||
|
constancy of diameter in longitudinal section, µm |
||
|
roundness, µm |
||
|
Surface roughness of the product sample: |
||
|
cylindrical internal Ra, µm |
||
|
flat end |
Figure 2. 5 - Semi-automatic cylindrical grinder 3M162
Table 2.9
Technical characteristics of semi-automatic cylindrical grinding machine 3M162
|
Characteristic |
Name |
|
|
Largest diameter of the workpiece, mm |
||
|
Maximum length of the workpiece, mm |
||
|
Grinding length, mm |
||
|
Accuracy |
||
|
Power |
||
|
Dimensions |
||
Tools used in the manufacture of the part.
1. Cutter (eng. toolbit) - a cutting tool designed for processing parts of various sizes, shapes, precision and materials. It is the main tool used for turning, planing and slotting work (and on corresponding machines). The cutter and the workpiece, rigidly fixed in the machine, come into contact with each other as a result of relative movement; the working element of the cutter is cut into the material layer and subsequently cut off in the form of chips. With further advancement of the cutter, the chipping process is repeated and chips are formed from individual elements. The type of chips depends on the machine feed rate, the rotation speed of the workpiece, the material of the workpiece, the relative position of the cutter and the workpiece, the use of coolant and other reasons. During operation, the cutters are subject to wear, so they must be re-sharpened.
Figure 2. 6, Cutter GOST 18879-73 2103-0057
Figure 2. 7 Cutter GOST 18877-73 2102-0055
2. Drill - a cutting tool with a rotary cutting movement and an axial feed movement, designed to make holes in a continuous layer of material. Drills can also be used for drilling, that is, enlarging existing, pre-drilled holes, and drilling, that is, obtaining non-through recesses.
Figure 2. 8 - Drill GOST 10903-77 2301-0057 (material R6M5K5)
Figure 2. 9 - GOST cutter 18873-73 2141-0551
3. Grinding wheels are designed for cleaning curved surfaces from scale and rust, for grinding and polishing products made of metals, wood, plastics and other materials.
Figure 2. 10 - Grinding wheel GOST 2424-83
Control tool
Technical control means: Vernier caliper ШЦ-I-125-0, 1-2 GOST 166-89; Micrometer MK 25-1 GOST 6507-90; Bore gauge GOST 9244-75 18-50.
The caliper is designed for high-precision measurements, capable of measuring the external and internal dimensions of parts, the depth of the hole. The caliper consists of a fixed part - a measuring ruler with a sponge and a moving part - a movable frame
Figure 2. 11 - Caliper ShTs-I-125-0, 1-2 GOST 166-89.
A bore gauge is a tool for measuring the internal diameter or distance between two surfaces. The accuracy of measurements with a bore gauge is the same as with a micrometer - 0.01 mm
Figure 2. 12 - Bore gauge GOST 9244-75 18-50
Micrometer is a universal instrument (device) designed for measuring linear dimensions by the absolute or relative contact method in the area of small sizes with low error (from 2 µm to 50 µm depending on the measured ranges and accuracy class), the conversion mechanism of which is a microscrew-nut pair
Figure 2. 13- Smooth micrometer MK 25-1 GOST 6507-90
2 .4 Development of workpiece basing schemes for operations and selection of devices
The basing and fastening scheme, technological bases, supporting and clamping elements and fixture devices must ensure a certain position of the workpiece relative to the cutting tools, the reliability of its fastening and the constancy of the basing throughout the entire processing process with a given installation. The surfaces of the workpiece taken as bases and their relative location must be such that the simplest and most reliable design of the device can be used, ensure ease of installation, fastening and removal of the workpiece, and the ability to apply clamping forces and supply of cutting tools in the right places.
When choosing bases, the basic principles of basing should be taken into account. In general, the full cycle of processing a part from roughing to finishing operations is carried out by sequentially changing sets of bases. However, in order to reduce errors and increase the processing productivity of parts, one must strive to reduce the reinstallation of the workpiece during processing.
If there are high requirements for processing accuracy for positioning workpieces, it is necessary to choose a positioning scheme that will ensure the smallest positioning error;
It is advisable to observe the principle of constancy of bases. When changing bases during the technological process, the processing accuracy decreases due to the error in the relative position of the new and previously used base surfaces.
Figure 2. 14 - Workpiece
In operations 005-020, 030, 045, the part is fixed in the centers and driven using a three-jaw chuck:
Figure 2. 15 - Operation 005
Figure 2. 16 - Operation 010
Figure 2. 17 - Operation 015
Figure 2. 18 - Operation 020
Figure 2. 19 - Operation 030
Figure 2. 20 - Operation 045
In operation 025, the part is secured in a vice.
Figure 2. 21 - Operation 025
In operation 035-040, the part is fixed in the centers.
Figure 2. 22 - Operation 035
To secure the workpiece during operations, the following devices are used: a three-jaw chuck, movable and fixed centers, a fixed support, a machine vice.
Figure 2. 23- Three-jaw chuck GOST 2675-80
Machine vice - a device for clamping and holding workpieces or parts between two jaws (movable and fixed) during processing or assembly.
Figure 2. 24- Machine vice GOST 21168-75
Center A-1-5-N GOST 8742-75 - machine rotating center; Machine centers are a tool used to fix workpieces when processing them on metal-cutting machines.
Figure 2. 25- Rotating center GOST 8742-75
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Development of a route technological process for manufacturing the “lower carrier housing” part. Description of the technological operation for milling grooves. Selection of equipment and cutting tools for this operation. Calculation of cutting mode parameters.
course work, added 12/15/2014
Development of a technological route for serial production of the “Splined Shaft” part. Determination of the structure of the technological process by transitions and installations. Description of equipment and tools. Calculation of cutting conditions. Calculation of technical time standards.
course work, added 12/23/2010
Description of the design and operation of the part. Justification of the type of production. Method for obtaining the workpiece. Development of route and operational technological process. Determination of cutting conditions and time standards. Calculation of measuring and cutting tools.
thesis, added 05/24/2015
Description of the purpose of the product, the composition of assembly units and incoming parts. Selection of materials, assessment of technological indicators of product design. Basic operations of the technological process of processing a part, development of machining modes.
course work, added 08/09/2015
Calculation of interoperational allowances, route technological process. Determination of cutting conditions and their standardization. Selection of basic equipment. Technological documentation (route and operational maps). Description of the part fixture.
course work, added 05/27/2015
Study of the operation of a vibroacoustic monitoring installation for large bearings. Development of the design of a radial loading unit. Analysis of the manufacturability of the design of the “Clamp” part. Selection of technological equipment and cutting tools.
thesis, added 10/27/2017
Description of the purpose of the part. Characteristics of a given type of production. Specifications for the material. Development of a technological process for manufacturing a part. Technical characteristics of the equipment. Control program for turning operation.
course work, added 01/09/2010
Analysis of the service purpose of the part, physical and mechanical characteristics of the material. Selecting the type of production, the form of organization of the technological process of manufacturing a part. Development of a technological route for surface treatment and part manufacturing.
course work, added 10/22/2009
The operating principle of a product, an assembly unit that includes a part. Part material and its properties. Justification and description of the method for obtaining the workpiece. Development of a part processing route. Calculation of cutting conditions. Organization of a turner's workplace.
thesis, added 02/26/2010
Structural and technological analysis of the assembly unit. Description of the design of the assembly unit and its relationship with other assembly units that make up the unit. Development of technological conditions for the manufacture of an assembly unit, assembly method.
Impossible without the use of various shaped parts.
Adapters are needed to switch from plastic to metal, as well as to connect pipe materials of different diameters.
Pipe adapters are connection adapters that help you assemble your piping system correctly and reliably. Such elements are used for the transition from plastic to metal (adapters), for connecting pipe materials of different diameters, and provide the necessary angle of rotation and branching of the pipeline. Structural parts are also called the newfangled English term “fittings”.
With the help of modern fittings, a pipeline system of any complexity can be assembled with minimal time and effort. Some adapters can be connected to using only your hands. This connection method is no less reliable than any other, and is used even for high-pressure pipes.
Installation of adapters for plastic pipes
Plastic adapters for the pipeline must be selected based on the composition of the pipes. They may be:
- polyethylene;
- polypropylene;
- polyvinyl chloride.
Installation of plastic adapter fittings is carried out in different ways. This does not require bulky equipment and a team of pipeline workers. The type of connection depends on the type of polymer, pipe diameter and purpose of the pipeline. Often there is a need to replace a section of pipeline that has rotted over time with a plastic pipe. Then you will need a connection between cast iron/steel and polymer pipes. Adapters come to the rescue. To connect you will need:
- A combined adapter with a metal threaded part (mostly brass) and a polymer socket with a rubber seal.
- Two adjustable wrenches.
- Teflon tape (tow).
Installation of plastic pipes is carried out in a socket, due to which a high-quality homogeneous seam is achieved.
Replacing an old pipe occurs very quickly. First, the coupling of the metal pipeline is unscrewed in the desired location. To do this, use two adjustable wrenches. Use one key to grasp the coupling, and the other to grasp the metal pipe. If the connection does not lend itself, then it should be lubricated with a special lubricant with an increased degree of penetration (Unisma-1, Molykote Multigliss).
At the next stage, when the old pipe is unscrewed, the threaded connections are sealed with Teflon tape in two or three turns. This small precaution helps prevent further leaks. The final stage is installing the adapter. Tighten the adapter carefully, without over-tightening, until resistance is felt.
Metal and polymer have different expansion coefficients during temperature fluctuations, so it is not recommended to use adapters with plastic threads on metal elements. In hot water supply and heating systems, for connection with metal valves and meters, it is worth using adapter brass couplings with a plastic body and a rubber seal.
Classification of adapters
Adapters are:
- compression;
- electric welded;
- flanged;
- threaded;
- reduction.
The type of connection depends on the type of polymer, pipe diameter and purpose of the pipeline.
A compression adapter is a crimp connection element for plastic water pipes. Such fittings are also used for wiring the pipeline system. Plastic compression parts can withstand pressure up to 16 atm. (up to 63 mm) and high temperature. They are not subject to lime deposits, rotting and other biological and chemical influences. Manufactured in standard diameters. They have such components as a cover-nut, a polypropylene body, a polyoxymethylene clamping ring, and a press-fit sleeve.
Installing the compression adapter
- Loosen the union nut and remove it.
- Disassemble the fitting into its component parts and put them on the plastic pipe in the same order.
- Insert the pipe firmly into the fitting until it stops completely.
- Tighten the adapter nut with a universal wrench (a crimp wrench is usually sold with the fittings).
The modern plumbing market today offers non-separable ones, but it is still difficult to say which ones are better.
When installing a compression fitting, a crimping element is formed on the pipe, which creates a tight connection. The clamping ring, the main part of the fitting, allows the connecting assembly to withstand colossal axial loads and jerks. Spontaneous unwinding caused by water vibration is prevented. Therefore, you won’t have to constantly tighten a loose nut.
A threaded adapter is a dismountable and assembled pipeline element that is used repeatedly. Threaded fittings can be either external or internal threaded. Such fittings are installed in those places where some additional installation, disassembly of the pipeline system and other work that would be impossible if the system were not dismountable would be required.
Threaded adapters do not require special equipment during installation. At the same time, they create a tight connection, preventing the leakage of water or gas from plastic pipelines. For more reliable sealing, FUM tape is additionally used, which is wound onto the thread in the direction of screwing the nut.
ZNE allow you to quickly install polyethylene pipelines using cheaper welding equipment for electrofusion welding.
An electric welded adapter (EWA) is a connecting element with an embedded electric heater, designed for different diameters. A heating coil built into the adapter melts the plastic at the pipe junction and creates a monolithic connection.
Installation of an electric welding adapter does not require special skills. The quality of electrofusion welding depends little on the person performing the work, which cannot be said about hardware welding.
Installing an electric welding adapter
The fastened parts are carefully aligned and joined in the required places. Electric current is passed through embedded electric heaters. Under the influence of electricity, the spiral heats up and causes the plastic planes to become viscous. The result is a monolithic compound at the molecular level.
When installing electric welding adapters, the following general requirements should be observed:
- the elements being welded must have an identical chemical composition;
- degreasing and thorough cleaning of surfaces;
- mechanical cleaning with tools;
- natural cooling.
According to the advice of experts, it is better to use ZNE adapters with an open heating coil. Plastic pipes must go deep into the fitting, and the welding zone must be of maximum length.
Flange Adapter or Compression Flange
This is a detachable connection element that provides permanent access to the pipeline section. The connecting unit is formed using two flanges and bolts that tighten them. For plastic pipes transitioning to metal elements, free-form flanges with a support point on a straight shoulder or a universal wedge connection with shaped flanges are most often used.
Before installation, the flange part must be inspected and all nicks and burrs that could damage the polymer pipe are identified. Then a step-by-step connection is made:
- pipes are cut strictly at right angles;
- flanges of the required size are installed;
- a rubber gasket is put on (the gasket must not be allowed to extend beyond the pipe cut by more than 10 mm);
- both flange rings slide onto the rubber gasket and are bolted together.
Such flanges will ensure the tightness and strength of the pipeline structure. They are easy to manufacture and convenient to install.
A reduction adapter is a connecting element for. This fitting is threaded and is often installed in assemblies connecting the pipe to meters and other distribution equipment.
Plastic pipes cannot be assembled into a pipeline system without a large set of fittings. The variety of these structural elements is amazing. It’s difficult to immediately figure out what’s what. Therefore, before assembling the pipeline, you should carefully study the entire rich assortment and choose only what you need. Very often, an unlucky craftsman who decides to change pipes ends up with a bunch of unnecessary parts at home. It's time to open a plumbing store yourself!
Introduction
The main trend in the development of modern engineering production is its automation in order to significantly increase labor productivity and the quality of products.
Automation of mechanical processing is carried out through the widespread use of CNC equipment and the creation of computer-controlled GPS systems on its basis.
When developing technological processes for processing parts in automated areas, it is necessary to solve the following problems:
improving the manufacturability of parts;
improving the accuracy and quality of workpieces; ensuring stability of the allowance; improvement of existing and creation of new methods for obtaining blanks that reduce their cost and metal consumption;
increasing the degree of concentration of operations and the associated complication of the structures of technological systems of machines;
development of progressive technological processes and structural layout diagrams of equipment, development of new types and designs of cutting tools and devices that ensure high productivity and quality of processing;
development of the aggregate and modular principle of creating machine tools, loading and transport devices, industrial robots, control systems.
Mechanization and automation of technological processes of machining involves the elimination or maximum reduction of manual labor associated with transportation, loading, unloading and processing of parts at all stages of production, including control operations, changing and setting tools, as well as work on collecting and processing chips.
The development of low-waste production technology provides for a comprehensive solution to the problem of manufacturing blanks and machining with minimal allowances through a radical technological re-equipment of procurement and machining shops using the most advanced technological processes, the creation of automatic and complex-automated lines based on modern equipment.
In such production, a person is freed from direct participation in the manufacture of the product. He retains the functions of preparing equipment, setting up, programming, and servicing computer equipment. The share of mental labor increases and the share of physical labor is reduced to a minimum. The number of workers is being reduced. The requirements for the qualifications of workers servicing automated production are increasing.
1. Calculation of output volume and determination of the type of production
Initial data for determining the type of production:
a) Volume of production of parts per year: N = 6500 pcs/year;
b) Percentage of spare parts: c = 5%;
c) Percentage of inevitable technological losses b = 5%;
d) Total production of parts per year:
e) part mass: m = 3.15 kg.
The type of production is determined approximately according to Table 1.1
Table 1.1 Organization of production by weight and volume of output
Weight of part, kgType of productionEMsSKsM <1,0<1010-20002000-7500075000-200000>2000001,0-2,5<1010-10001000-5000050000-100000>1000002,5-5,0<1010-500500-3500035000-75000>750005,0-10<1010-300300-2500025000-50000>50000>10<1010-200200-1000010000-25000>25000
In accordance with the table, the processing of parts will be carried out in medium-scale production conditions, approaching small-scale production.
Serial production is characterized by the use of specialized equipment, as well as numerically controlled machines and automated lines and sections based on them. Devices, cutting and measuring tools can be either special or universal. The scientific and methodological basis for organizing mass production is the introduction of group technology based on design and technological unification. The arrangement of equipment, as a rule, is along the technological process. Automatic trolleys are used as means of interoperational transportation.
In mass production, the number of parts in a batch for simultaneous launch can be determined in a simplified way:
where N is the annual parts production program, pcs.;
a - the number of days for which it is necessary to have a supply of parts (frequency of launch - release, corresponding to the needs of the assembly);
F - number of working days in a year.
2. General characteristics of the part
1 Service purpose of the part
"Adapter". The adapter operates under static loads. Material - Steel 45 GOST 1050-88.
Presumably this part does not work in difficult conditions - it is used to connect two flanges with different mounting holes. Perhaps the part is part of a pipeline in which gases or liquids circulate. In this regard, quite high requirements are placed on the roughness of most internal surfaces (Ra 1.6-3.2). They are justified, since low roughness reduces the possibility of creating additional sources of oxidation processes and promotes the unhindered flow of liquids, without strong friction and turbulent turbulence. The end surfaces have a rough roughness, since, most likely, the connection will be made through a rubber gasket.
The main surfaces of the part are: cylindrical surfaces Æ 70h8; Æ 50H8+0.039, Æ 95H9; threaded holes M14x1.5-6N.
2.2 Part type
The part refers to parts of the type of bodies of revolution, namely a disk (Fig. 1.). The main surfaces of the part are external and internal cylindrical surfaces, external and internal end surfaces, internal threaded surfaces, that is, surfaces that determine the configuration of the part and the main technological tasks for its manufacture. Non-main surfaces include various chamfers. The classification of treated surfaces is presented in table. 2.1
Rice. 1. Sketch of the part
Table 2.1 Classification of surfaces
No. Execution sizeSpecified parametersRa, µmTf, µmTras, µm1NTP, IT=12, Lс=1012.5--2NTSP Æ 70 h81.6--3NTP, IT=12, Luс=2512.5-0.14NTP Æ 120 h1212.5--5NTP, IT=12, Lус=1412.5--6ФП IT=10, L=16.3--7NTP Æ 148 h1212.5--8FP IT=10, L=16.3-- 9 NTP, IT=12, Lс=26.512.5-- 10VTsP Æ 12 N106.3--11VTsP Æ 95 Н93.2--12ВТП, IT=12, Lус=22.512.5--13ВЦП Æ 50 N81.6--14VTsP Æ 36 Н1212.5--15ВТП, IT=12, Lус=1212.5--16ВЦП Æ 12,50,01-17FP IT=10, L=1,56,3--18FP IT=10, L=0,56,3-- 19 VRP, М14х1,5 - 6Н6,30,01- 20ВЦП R= 9 Н1212.5-- The characteristic processing features of this part are the following:
the use of CNC turning and grinding machines as the main group of equipment;
processing is carried out when installed in a chuck or fixture;
the main processing methods are turning and grinding of external and internal cylindrical and end surfaces, threading with a tap;
It is advisable to prepare the bases (cutting the ends) for this type of production on a lathe.
high requirements for roughness require the use of finishing processing methods - grinding.
2.3Part manufacturability analysis
The purpose of the analysis is to identify design flaws based on information from the part drawing, as well as possible improvement of the design.
The “Adapter” part has cylindrical surfaces, which leads to a reduction in equipment, tools and fixtures. When processing, the principle of constancy and unity of bases, which are the surface, is observed. Æ 70 h8 and the end of the part.
all surfaces are easily accessible for processing and control;
metal removal is uniform and shock-free;
there are no deep holes;
All surfaces can be processed and inspected using standard cutting and measuring tools.
The part is rigid and does not require the use of additional devices - rests - during processing to increase the rigidity of the technological system. As a low-tech feature, we can note the lack of unification of such elements as external and internal chamfers - there are three standard sizes for ten chamfers, which leads to an increase in the number of cutting and measuring tools.
2.4Standard control and metrological examination of the part drawing
2.4.1 Analysis of the standards used in the drawing
In accordance with the requirements of the ESKD, the drawing must contain all the necessary information that gives a complete picture of the part, have all the necessary sections and technical requirements. Special areas of the form are highlighted separately. The original drawing meets these requirements completely. One groove is highlighted and referenced in the drawing. Textual requirements for shape tolerances are indicated by symbols directly on the drawing, and not in the technical requirements. The callout is indicated by a letter rather than a Roman numeral. It should be noted the designation of surface roughness, made taking into account amendment No. 3 of 2003, as well as unspecified tolerances of size, shape and location. Maximum dimensional deviations are indicated mainly by qualifications and numerical values of deviations, as is customary in medium-scale production, since control can be carried out by both special and universal measuring instruments. The inscription “Unspecified maximum deviations according to OST 37.001.246-82” in the technical requirements should be replaced with the inscription “Unspecified dimensions and maximum deviations of the dimensions, shape and location of treated surfaces - according to GOST 30893.2-mK”
4.2 Checking compliance of the specified maximum deviations with standard tolerance fields in accordance with GOST 25347
The drawing contains maximum dimensional deviations, which are indicated only by numerical values of the maximum deviations. Let's find the corresponding tolerance fields according to GOST 25347 (Table 2.2).
Table 2.2. Compliance of specified numerical deviations with standard tolerance fields
SizeTolerance range js10 Æ H13
Analysis of table 2.2. shows that the vast majority of sizes have maximum deviations corresponding to the standard ones.
4.3 Determination of maximum dimensional deviations with unspecified tolerances
Table 2.3. Maximum dimensional deviations with unspecified tolerances
SizeTolerance rangeMaximum deviations57js12 5js12 Æ 36H12-0.1258js12 R9H12-0.1592js12 Æ 148h12+0.4 Æ 118H12-0.35 Æ120h12+0.418js12 62js12
2.4.4 Analysis of compliance of shape and roughness requirements with size tolerance
Table 2.4. Compliance with shape and roughness requirements
No. Execution size Specified parameters Design parameters Ra, µmTf, µmTras, µmRa, µmTf,. µmTras, µm1NTP, IT=12, Luс=1012.5--3.2--2NTP Æ 70 h81.6--1.6--3NTP, IT=12, Luс=2512.5-0.11.6-0.14NTP Æ 120 h1212.5--1.6--5NTP, IT=12, Lс=1412.5--1.6--6FP IT=10, L=16.3--6.3--7NTP Æ 148 h1212.5--12.5--8FP IT=10, L=16.3--6.3-- 9 NTP, IT=12, Lс=26.512.5--3.2--10VTsP Æ 12 N106.3--3.2--11VTsP Æ 95 Н93.2--1.6--12ВТП, IT=12, Lус=22.512.5--6.3--13ВЦП Æ 50 N81.6--1.6--14VTsP Æ 36 Н1212.5--12.5--15ВТП, IT=12, Lус=1212.5--6.3--16ВЦП Æ 12.50.01-250.01-17FP IT=10, L=1.56.3--6.3--18FP IT=10, L=0.56.3--6.3-- 19 GRP , М14х1,5 - 6Н6,30,01-6,30,01- 20ВЦП R=9 Н1212,5--6,3--
Conclusions to the table: the calculated roughness for a number of sizes is less than the specified one. Therefore, for free surfaces 5,10,12,15,16,20 we assign the calculated roughness as more appropriate. The calculated location tolerances for surface 3 are the same as those specified in the drawing. We make the appropriate corrections to the drawing.
2.4.5 Analysis of the correct choice of bases and location tolerances
In the analyzed drawing, two location tolerances relative to the cylindrical surface and the right end are specified: tolerances for the position and perpendicularity of threaded holes and flange holes of 0.01 mm, as well as a tolerance for parallelism of the end of 0.1 mm. You should choose other bases, since these will be inconvenient to base the part in the fixture when processing radial holes. Base B should be changed to the axis of symmetry.
cutting turning adapter workpiece
3. Selecting the type of workpiece and its justification
The method for obtaining a blank part is determined by its design, purpose, material, technical requirements for manufacturing and its efficiency, as well as production volume. The method of obtaining a workpiece, its type and accuracy directly determine the accuracy of machining, labor productivity and the cost of the finished product.
For the serial type of production, it is advisable to assign a blank - stamping, as close as possible to the configuration of the part.
Forging is one of the main methods of metal forming (MMD). Giving the metal the required shape, as closely as possible corresponding to the configuration of the future part and obtained with the least labor costs; correction of cast structure defects; improving the quality of metal by transforming a cast structure into a deformed one and, finally, the very possibility of plastic deformation of metal-plastic alloys are the main arguments for the use of metal forming processes.
Thus, improvement in the quality of the metal is achieved not only during its smelting, casting and subsequent heat treatment, but also in the process of metal machining. It is plastic deformation, correcting defects in the cast metal and transforming the cast structure, that gives it the highest properties.
So, the use of metal forming processes in the mechanical engineering industry allows not only to significantly save metal and increase the productivity of workpiece processing, but also makes it possible to increase the service life of parts and structures.
The technological processes of low-waste production of workpieces include: production of precise hot-stamped workpieces with minimal waste in burr, production of workpieces by cold die forging or with heating. Tables 3.1 and 3.2 show the mechanical properties and chemical composition of the workpiece material.
Table 3.1 - Chemical composition of the material Steel 45 GOST 1050-88
Chemical element % Silicon (Si) 0.17-0.37 Copper (Cu), no more than 0.25 Arsenic (As), no more than 0.08 Manganese (Mn) 0.50-0.80 Nickel (Ni), no more than 0.25 Phosphorus (P), no more than 0.035 Chromium (Cr), no more than 0.25 Sulfur (S), no more than 0.04
Table 3.2 - Mechanical properties of the workpiece material
Steel grade Cold-worked condition After annealing or high tempering, MPad, %w, %w, MPad, %w,%Steel 456406305401340
A disk blank can be obtained in several ways.
Cold extrusion on presses. The cold extrusion process involves a combination of five types of deformation:
direct extrusion, reverse extrusion, upsetting, trimming and punching. For cold extrusion of workpieces, hydraulic presses are used, which make it possible to automate the process. Setting the maximum force at any point of the slide stroke on hydraulic presses allows for stamping parts of large lengths.
Forging on a horizontal forging machine (HFM), which is a horizontal mechanical press, in which, in addition to the main deforming slide, there is a clamping one that clamps the deformed part of the rod, ensuring its upset. The stops in the GKM dies are adjustable, which makes it possible during adjustment to clarify the deformed volume and obtain a forging without flash. The dimensional accuracy of steel forgings can reach 12-14 quality, surface roughness parameter Ra12.5-Ra25.
The determining factors for choosing a method for producing blanks are:
precision of workpiece manufacturing and quality of its surface.
closest approximation of the dimensions of the workpiece to the dimensions of the part.
The choice of the method for obtaining the workpiece was based on an analysis of possible production methods, the implementation of which can help improve technical and economic indicators, i.e. achieving maximum efficiency while ensuring the required product quality.
The resulting forgings are subjected to preliminary heat treatment.
The purpose of heat treatment is:
elimination of the negative consequences of heating and pressure treatment (removal of residual stresses, evaporation of overheating);
improving the machinability of the workpiece material by cutting;
preparing the metal structure for final maintenance.
After maintenance, the forgings are sent for surface cleaning. A sketch of the workpiece is presented in the graphic part of the diploma project.
As one of the options for obtaining a workpiece, we will accept the production of workpieces using the cold die stamping method. This method makes it possible to obtain stampings that are closer to the finished part in shape and dimensional accuracy than stampings obtained by other methods. In our case, if it is necessary to manufacture a precision part, the minimum surface roughness of which is Ra1.6, obtaining a workpiece by cold die forging will significantly reduce blade processing, reduce metal consumption and machine-tool processing intensity. The average metal utilization factor for cold die forging is 0.5-0.6.
4. Development of a route technological process for manufacturing a part
The determining factor in the development of a route technological process is the type and organizational form of production. Taking into account the type of part and the type of surfaces being processed, a rational group of machines is installed for processing the main surfaces of the part, which increases productivity and reduces the processing time of the part.
In general, the processing sequence is determined by the accuracy, roughness of surfaces and the accuracy of their relative position.
When choosing the standard size and model of a machine, we take into account the dimensions of the part, its design features, assigned bases, the number of positions in the setup, the number of potential positions and setups in the operation.
To process the main surfaces of a group of given parts, we will use equipment that has the property of quick changeover for processing any of the parts of the group, i.e. possessing flexibility and, at the same time, high productivity, due to the possible concentration of operations, which leads to a reduction in the number of installations; assignment of intensive cutting conditions, due to the use of advanced tool materials, the possibility of complete automation of the processing cycle, including auxiliary operations, such as installation and removal of parts, automatic control and replacement of cutting tools. These requirements are met by numerically controlled machines and flexible production complexes built on their basis.
In the designed version we will adopt the following technical solutions.
To process external and internal cylindrical surfaces, we select lathes with numerical control.
For each surface, a standard and individual plan for its processing is assigned, while we select economically feasible methods and types of processing when performing each technological transition in accordance with the accepted equipment.
The development of route technology means the formation of the content of the operation and the sequence of their implementation is determined.
Basic and non-basic elementary and standard surfaces are identified, since the general sequence of processing the part, and the main content of the operation will be determined by the sequence of processing only the main surfaces, as well as the equipment used, characteristic of mass production and the type of workpiece obtained by hot stamping.
For each elementary surface of a part, standard processing plans are assigned in accordance with the specified accuracy and roughness.
The processing stages of a part are determined by the processing plan for the most accurate surface. The assigned part processing plan is presented in table. 4.1. Processing of non-main surfaces is carried out at the semi-finished stage of processing.
Table 4.1 Technological information on the workpiece
Surface No. Surface to be processed and its accuracy, ITRa, µm Options Options for surface treatment plans final method and type of processing Type of processing (stages) (Shpch)Tch (Fch) (Shch)2NTsP Æ 70 h81.6Turning (grinding, milling) of increased accuracyTchr (Fchr) (Shchr)Tpch (Fpch) (Shpch)Tch (Fpch) (Shch)Tp (Fp) (Shp)3NTP, IT=12, Luс=251.6Turning ( grinding, milling) of increased accuracy Tchr (Fchr) (Shchr) Tpch (Fpch) (Shpch) Tch (Fch) (Shch) Tp (Fp) (Shp) 4NTsP Æ 120 h121.6Turning (grinding, milling) of increased accuracyTchr (Fchr) (Shchr)Tpch (Fpch) (Shpch)Tch (Fch) (Shch)Tp (Fp) (Shp)5NTP, IT=12, Luс=141.6Turning ( grinding, milling) of increased precisionTchr (Fchr) (Shchr)Tchr (Fpch) (Shpch)Tch (Fch) (Shch)Tp (Fp) (Shp)6FP IT=10, L=16.3Semi-finish turning (grinding, milling)Tchr (Fchr) (Shchr)Tpch (Fpch) (Shpch)7NTsP Æ 148 h1212.5 Rough turning (grinding, milling) Tchr (Fchr) (Shchr) 8FP IT=10, L=16.3 Semi-finish turning (grinding, milling) Tchr (Fchr) (Shchr) Tpch (Fpch) (Shchr) 9 NTP, IT=12, Luс=26.53.2 Rough turning (grinding, milling) Tchr (Fchr) (Shchr) Tpch (Fpch) (Shpch) Tch (Fch) (Shch) 10VTsP Æ 12 N106.3 Countersinking (semi-finish drilling) SvchrZ (Svpch) 11VTsP Æ 95 N91.6 Boring (milling, grinding) of increased precision Rchr (Fchr) Rpch (Fpch) (Shpch) Rch (Fch) (Shch) Rp (Fp) (Shp) 12VTP, IT=12, Lus=22.512.5 Boring (milling) draftRchr (Fchr) 13VTsP Æ 50 N81.6 Boring (milling, drilling, grinding) of increased accuracyRchr (Fchr) (Svchr) Rpch (Fpch) (Shpch) (Svpch)Rch (Fch) (Shch) (Svch)Rp (Fp) (Shp) (Svp)14VTsP Æ 36 Н1212.5 Rough drilling (milling) Svchr (Fchr) 15 VTP, IT = 12, Luс = 1212.5 Countersinking (milling) Zchr (Fchr) 16 VCP Æ 12.5 Rough drilling Svchr17FP IT=10, L=1.56.3 CountersinkingZ18FP IT=10, L=0.56.3 CountersinkingZ 19 VRP, M14x1.5 - 6N6.3 Finish thread cuttingN 20VTsP R=9 N1212.5 Rough millingFchr Table 4.1 shows not the only processing plans, but several variants of plans. All of the above options may occur in the processing of a given part, but not all of them are appropriate for use. The classic processing plan, which is shown in the table without brackets, is a universal processing option that contains all possible stages for each surface. This option is suitable for cases where production conditions, equipment, workpieces, etc. are unknown. Such a processing plan is common in obsolete production, when parts are manufactured on worn-out equipment, which makes it difficult to maintain the required dimensions and ensure accuracy and roughness parameters. We are faced with the task of developing a promising technological process. In modern production, stages are not used in its classical sense. Nowadays, fairly precise equipment is produced, the processing of which is carried out in two stages: roughing and finishing. Exceptions are made in some cases, for example, when the part is not rigid, additional intermediate steps may be introduced to reduce the pressing cutting forces. Roughness parameters, as a rule, are provided by cutting conditions. The processing options presented in the table can alternate, for example, after rough turning there is semi-finish milling or grinding. Considering that the workpiece is produced by cold die stamping, which provides 9-10 quality, it is possible to eliminate roughing, since the surfaces of the workpiece will be initially more accurate.
Table 4.2
Surface No. Surface to be machined and its accuracy, ITRa, µm Final method and type of processing Surface treatment plan Type of processing (stages) EchrEpchEchEpEotd1NTP, IT=12, Luс=103.2 Finish turning Æ 70 h81.6 High-precision turning TpchTp3NTP, IT=12, Luс=251.6 High-precision turning TpchTp4NTSP Æ 120 h121.6 High-precision turning TpchTp5NTP, IT=12, Lус=141.6 High-precision turning TpchTp6FP IT=10, L=16.3 Semi-finish turning Tpch7NTsP Æ 148 h1212.5 Rough turning Tchr8FP IT=10, L=16.3 Semi-finish turning Tpch9NTP, IT=12, Lс=26.53.2 Finish turning Tpch Tch10VTsP Æ 12 N106.3 Semi-finish drilling Svpch11VTsP Æ 95 N91.6 Increased precision boring RpchRp12VTP, IT=12, Luс=22.512.5 Rough boring RpchRp13VTsP Æ 50 N81.6 High precision boring RpchRp14VTsP Æ 36 N1212.5 Rough milling Sv15VTP, IT=12, Luс=12 12.5 MillingFrch16VTsP Æ 10
Taking into account all of the above, a potential technical process can be formed.
After identifying the content of potential transition operations, their content is clarified by the number of installations and the content of transitions. The content of potential operations is given in Table. 4.3.
Table 4.3. Formation of a potential processing route
Stages of part processing Contents of a potential operation Type of machine in the stage Number of potential installations Installation Operation Echr Tchr7, Rchr12 CNC lathe, class. N1A005Sv14, F15, Sv16, Fchr20 Vertical milling, class N2A B010 EpchTpch1, Tpch2, Tpch3, Tpch4, Tpch5, Tpch6, Tpch8, Tpch9, Rpch11, Rpch13 CNC lathe, class. N2A B015Sv10, Z17, Z18 Vertical drilling machine, class N1A020EchTch1, Tch9 CNC lathe, class. N2A B025EpTp2, Tp3, Tp4, Tp5, Rp11, Rp13 CNC lathe, class. P2A B030
The content of the operation of the technological route is formed according to the principle of maximum concentration when performing installations, positions and transitions, therefore we replace the equipment assigned in the potential processing route to a CNC machining center, on which the part will be completely processed in 2 installations. We select a two-spindle OC; the settings are changed automatically using the machine. Positioning of the part according to the location of the radial holes after installation is also ensured by the machine tools using spindle angular position sensors.
Table 4.4. Formation of a real preliminary route for processing a part in mass production conditions
No. of operation Installations No. of positions in the installation Stages of processing Bases Contents of operation Equipment correction 005 АIЭпч7.9 Тпч1, Тпч2, Тпч3, Тпч4, Тпч5, Тпч6 CNC machining center, class. P II Rpch13IIIEchTch1IVEpTp2, Tp3, Tp4, Tp5 V Rp13VI EchrFchr20BIEchr1.4 Tchr7 II Rchr12 III EpchTpch8, Tpch9 IV Ech Tch9 VEpch Rpch11, Rp11 VIEchrSv14 VII F15VIII Sv16 IXEpch Sv10 X 17, Z18 XIН
Having analyzed the data presented in tables 4.5 and 4.6, we make a choice in favor of the technological process option presented in table 4.7. The chosen option is promising, has modern equipment and a modern, precise method for producing a workpiece, which allows reducing the amount of machining by cutting. Based on the generated real processing route, we will record the route technological process in the route map.
Table 4.5. Route map of the technological process
Part name Adapter
Material Steel 45
Type of workpiece: Stamping
No. of operations. Name and brief content of the operation Bases Type of equipment 005 CNC lathe A. I. Sharpen 1,2,3,4,5,6 (Epch) 7.9 Dual-spindle turning and milling processing center, class. P 1730-2M CNC lathe A. II. Boring 13 (Epch) CNC turning A. III. Turn 1 (Ech) CNC turning A. IV. Turn 2,3,4,5 (Ep) CNC turning A. V. Boring 13 (Ep) CNC milling A. VI. Mill a cylindrical recess 20 (Echr) CNC lathe B. I. Turn 7 (Echr) 1.4 CNC lathe B. II. Boring 12 (Echr) CNC lathe B. III. Turn 8.9 (Epch) CNC lathe B. IV. Turn 9 (Ech) CNC turning B. V. Boring 11 (Epch, Ep) CNC drilling B. VI. Drill 14 (Edr) CNC milling B. VII. Milling 15 (Echr) CNC drilling B. VIII. Drill 16 (Echr) CNC drilling machine B. IX. Drill 10 (Epch) CNC milling B. X. Countersink 17.18 (Epch) CNC threading B. XI. Cut thread 19 (EPCH)
5. Development of operational technological process
1 Equipment clarification
The main type of equipment for processing parts such as rotating bodies, in particular shafts, in medium-scale production conditions are lathes and cylindrical grinding machines with computer numerical control (CNC). For threaded surfaces - thread rolling machines, for milling grooves and flats - milling machines.
To process the main cylindrical and end surfaces, we leave a pre-selected turning-milling dual-spindle machining center 1730-2M of increased accuracy class. The technological capabilities of such a machine include turning cylindrical, conical, shaped surfaces, processing center and radial holes, milling surfaces, and threading small-diameter holes. When installing a part, the basing scheme is taken into account, which determines the dimensions. The characteristics of the accepted equipment are indicated in Table 5.1.
Table 5.1. Technical parameters of the selected equipment
Name of machine max, min-1Ndv, kW Tool magazine capacity, pcs Maximum part dimensions, mm Overall dimensions of the machine, mm Weight, kg Machine accuracy class 1730-2М350052-800х6002600x3200x39007800П
5.2Clarification of the part installation diagram
The installation schemes chosen during the formation of the actual technological processing process do not change after the equipment is specified, since with this basing scheme it is possible to implement rational sizing, taking into account the processing of the part on a CNC machine, and also these bases have the largest surface area, which ensures the greatest stability of the part during processing. The part is processed completely on one machine in one operation, consisting of two setups. In this way, it is possible to minimize processing errors caused by the accumulation of errors during successive reinstallations from stage to stage.
5.3Purpose of cutting tools
Cutting tools are used to form the required shape and size of workpiece surfaces by cutting, cutting off relatively thin layers of material (chips). Despite the great differences between individual types of instruments in purpose and design, they have much in common:
working conditions, general structural elements and methods of their justification, principles of calculation.
All cutting tools have a working and fastening part. The working part performs the main service purpose - cutting, removing an excess layer of material. The fastening part is used to install, base and secure the tool in the working position on the machine (technological equipment); it must withstand the force load of the cutting process and ensure vibration resistance of the cutting part of the tool.
The choice of tool type depends on the type of machine, processing method, material of the workpiece, its size and configuration, required accuracy and roughness of processing, type of production.
The choice of material for the cutting part of the tool is of great importance for increasing productivity and reducing processing costs and depends on the adopted processing method, the type of material being processed and working conditions.
Most designs of metal-cutting tools are made - the working part is made of tool material, the fastening part - from ordinary structural steel 45. The working part of the tool - in the form of plates or rods - is connected to the fastening part by welding.
Hard alloys in the form of multifaceted carbide plates are secured with clamps, screws, wedges, etc.
Let's consider using the tool for operations.
In turning operations of processing a part, we use cutters (contour and boring) as cutting tools.
On cutters, the use of multifaceted carbide non-sharpening inserts ensures:
increased durability by 20-25% compared to soldered cutters;
the possibility of increasing cutting conditions due to the ease of restoring the cutting properties of multifaceted inserts by rotating them;
reduction: tool costs by 2-3 times; losses of tungsten and cobalt by 4-4.5 times; auxiliary time for changing and regrinding cutters;
simplification of instrumental management;
reducing abrasive consumption.
T5K10 hard alloy is used as a material for replaceable cutter plates for processing steel 45 for rough and semi-finish turning, and T30K4 for finishing turning. The presence of chip-breaking holes on the surface of the plate allows the resulting chips to be crushed during processing, which simplifies their disposal.
We choose the method of attaching the plate - a wedge clamp for the roughing and semi-finishing stages of processing and a double-arm clamp for the finishing stage.
A contour cutter with c = 93° with a triangular plate for the semi-finishing stage of processing and with c = 95° with a rhombic plate (e = 80°) made of hard alloy (TU 2-035-892) for the finishing stage is accepted (Fig. 2.4 ). This cutter can be used when turning the NC, when trimming ends, when turning a reverse cone with a fall angle of up to 30 0, when processing radius and transition surfaces.
Figure 4. Cutter sketch
To drill holes, twist drills in accordance with GOST 10903-77 from high-speed steel R18 are used.
For processing threaded surfaces - taps made of high-speed steel P18.
4 Calculation of operational dimensions and workpiece dimensions
We provide a detailed calculation of diametrical dimensions for the surface Æ 70h8 -0,046. For clarity, we accompany the calculation of diametrical operational dimensions by constructing a diagram of allowances and operational dimensions (Fig. 2).
Shaft blank - stamping. Technological route for surface treatment Æ 70h8 -0,046 consists of semi-finish and high precision turning.
We calculate the diametrical dimensions in accordance with the diagram using the formulas:
dpchtakh = dpov max + 2Z pov min + Tzag.
The minimum value of the allowance 2Zimin when processing external and internal cylindrical surfaces is determined:
2Z imin = 2((R Z + h) i-1 + ?D 2S i-1 + e 2 i ), (1)
where R Zi-1 - height of profile irregularities at the previous transition; h i-1 - depth of the defective surface layer at the previous transition; ; D S i-1 - total deviations of the surface location (deviations from parallelism, perpendicularity, coaxiality, symmetry, intersection of axes, positional) and in some cases deviations of the surface shape; c is the error in installing the workpiece at the transition being performed;
R value Z and h, which characterizes the surface quality of stamped workpieces, is 150 and 150 μm, respectively. R values Z and h, achieved after machining, are found from the Total value of spatial deviations for workpieces of this type is determined:
where is the general deviation of the workpiece location, mm; - deviation of the workpiece location during alignment, mm.
The warping of the workpiece is determined by the formula:
where is the deviation of the part axis from straightness, µm per 1 mm (specific curvature of the workpiece); l is the distance from the section for which we determine the magnitude of the deviation of the location to the place of fastening the workpiece, mm;
where Тз =0.8 mm is the tolerance for the diametrical size of the base of the workpiece used for centering, mm.
µm=0.058 mm;
For intermediate stages:
where Ku is the refinement factor:
semi-finish turning K = 0.05;
high precision turning K= 0.03;
We get:
after semi-finish turning:
r2=0.05*0.305=0.015 mm;
after high precision turning:
r2=0.03*0.305=0.009 mm.
The tolerance values for each transition are taken from the tables in accordance with the quality of the type of processing.
The error values for the installation of the workpiece are determined according to the “Handbook of Mechanical Engineering Technologists” for stamped workpieces. When installed in a three-jaw lathe chuck with a hydraulic power unit, e i = 300 microns.
In the column, the maximum dimensions dmin are obtained from the calculated dimensions, rounded to the accuracy of the tolerance of the corresponding transition. The largest maximum dimensions dmax are determined from the smallest maximum dimensions by adding the tolerances of the corresponding transitions.
We determine the allowance values:
Zminpc = 2 × ((150 + 150) + (3052+3002)1/2) = 1210 µm = 1.21 mm
Zminp.t. = 2 × ((10 + 15) + (152+3002)1/2) =80 µm = 0.08 mm
We determine Zmax for each processing stage using the formula:
Zmaxj= 2Zminj +Тj+Тj-1
Zmaxпч = 2Zmincher + Tzag + Тcher = 1.21 + 0.19 + 0.12 = 1.52 mm.
Zmaxp.t. = 0.08 + 0.12 +0.046 = 0.246 mm.
All the results of the calculations are summarized in Table 5.2.
Table 5.2. Results of calculations of allowances and maximum dimensions for technological transitions to processing Æ 70h8 -0,046
Technological transitions of surface treatment. Allowance elements, µmCalculated allowance 2Z min, µmInstallation error e i, µmBefore start , mmLimit size, mmLimit values of allowances, mmExecutive size dRZT dmindmax Blank (stamping) 1501503053000.1971.4171.6--71.6-0.19 Semi-finish turning 15015030512103000.1270.0870.21.211.5270.2-0.12 High precision turning 10159803000.04669.9 54700.080.24670-0.046
The diametrical dimensions are determined similarly for the remaining cylindrical surfaces. The final results of the calculation are given in Table 5.3.
Figure 2. Diagram of diametric dimensions and allowances
Table 5.3. Operating diametrical dimensions
Processed surface Technological processing transitions Installation error e i, µm Minimum diameter Dmin, mm Maximum diameter Dmax, mm Minimum allowance Zmin, mm Tolerance T, mm Operational size, mm NCP Æ 118h12 Blank-stamping Sub-finish turning High precision turning 300120.64 118.5 117.94120.86 18.64 118- 2 0.50.22 0.14 0.054120.86-0.22 118.64-0.14 118-0.054NTsP Æ 148h12 Blank-stamping Rough turning0152 147.75152.4 148- 40.4 0.25152.4-0.4 148-0.25 TCP Æ 50H8+0.039 Blank-stamping Semi-finish boring High precision boring 30047.34 49.39 50.03947.5 49.5 50- 2 0.50.16 0.1 0.03947.5-0.16 49.5-0, 1 50+0.039 TCP Æ 95Н9+0.087 Blank-stamping Semi-finish boring High precision boring 092.33 94.36 95.08792.5 94.5 95- 2 0.50.22 0.14 0.05492.5-0.22 94.5-0, 14 95+0.087
Calculation of linear operating dimensions
We present the sequence of formation of linear dimensions in the form of Table 5.4
Table 5.4. Sequence of formation of linear dimensions
No. of operations. Installation Position Contents of operation Equipment Sketch of processing 005 AI Turn 1, 2, 3, 4, 5, 6 (Epch), maintaining dimensions A1, A2, A3 Dual-spindle turning and milling center, class. P 1730-2M IIWaste 13 (Epch) 005AIIITurn 1 (Ech), maintaining size A4Twin-spindle turning and milling processing center, class. P 1730-2M IVGrind 2,3,4,5 (Ep), maintaining size A5, A6 005AVBore 13 (Ep) Dual-spindle turning and milling machining center, class. P 1730-2M VIMill a cylindrical recess 20 (Echr), maintaining size A7 005BITochit 7 (Echr) Dual-spindle turning and milling processing center, class. P 1730-2M IBore 12 (Echr), maintaining size A8 005BIIITurn 8.9 (Epch), maintaining size A9 Double-spindle turning and milling processing center, class. P 1730-2M IVSharpen 9 (Eh), maintaining size a10 005БVBore 11 (Epch, Ep) Dual-spindle turning and milling machining center, class. P 1730-2M VIDrill 14 (Edr), maintaining size A11 005БVIIMill 15 (Echr), maintaining size A12 Dual-spindle turning and milling processing center, class. P 1730-2M VIIIDrill 16 (Edr) 005BIXDrill 10 (Epch)Twin-spindle turning and milling processing center, class. P 1730-2M XCountersink 17 (Epch) 005BX Countersink 18 (Epch) Dual-spindle turning and milling processing center, class. P 1730-2M XITap thread 19 (EPCH)
The calculation of linear operational dimensions is accompanied by the construction of a diagram of allowances and operational dimensions in Fig. 3, drawing up equations for dimensional chains, calculating them and ending with determining all dimensions of the workpiece. The smallest allowances required for calculations are taken according to.
Let's create equations for dimensional chains:
D5 = A12- A4 + A6
Z A12 = A11- A12
Z A11 = A10- A11
Z A10 = A9- A10
Z A9 = A4- A9
Z A8 = A4 - A8 - Z4
Z A7 = A5- A7
Z A6 = A2- A6
Z A5 = A1- A5
Z A4 = A3- A4
Z A3 = Z3- A3
Z A2 = Z2- A2
Z A1 = Z1- A1
Let us give an example of calculating operational dimensions for equations with a closing link - design size and for three dimensional chains with a closing link - allowance.
Let's write down the equations of dimensional chains with a closing link - design size.
D5 = A12 - A4 + A6
Before solving these equations, it is necessary to ensure that the tolerances for the design dimension are assigned correctly. To do this, the tolerance equation must be fulfilled:
Let us assign economically feasible tolerances to the operating dimensions:
for the high-precision stage - 6th grade;
for the stage of increased accuracy - 7th grade;
for the finishing stage - 10th grade;
for the semi-finishing stage - 11th grade;
For the draft stage - 13th grade.
TA12= 0.27mm
T A11= 0.27 mm,
TA10= 0.12 mm,
TA9= 0.19 mm,
TA8= 0.46 mm,
T A7 = 0.33 mm,
T A6= 0.03 mm,
T A5= 0.021 mm,
TA4=0.12 mm,
T A3= 0.19 mm,
T A2= 0.19 mm,
T A1= 0.13 mm.
D5 = A12 - A4 + A6,
TD5= 0.36 mm
36>0.27+0.12+0.03=0.42 mm (the condition is not met), we tighten the tolerances on the component links within the technological capabilities of the machines.
Let's assume: TA12=0.21 mm, TA4=0.12 mm.
360.21+0.12+0.03 - the condition is met.
We solve equations for dimensional chains with a closing link - an allowance. Let us determine the operational dimensions necessary to calculate the above equations. Let's consider an example of calculating three equations with a closing link - an allowance limited to a minimum value.
)Z A12 = A11 - A12, (rough milling op.005).
Z А12 min = A 11 min - A 12 max .
Let's calculate Z А12 min . Z А12 min determined by errors that arise when milling a cylindrical recess at the roughing stage.
Let us assign Rz=0.04 mm, h=0.27 mm, =0.01 mm, =0 mm (installation in the chuck). The value of the allowance is determined by the formula:
Z12 min = (RZ + h)i-1 + D2Si-1 + e 2i ;
Z12 min = (0.04 + 0.27) + 0.012+ 02 = 0.32 mm.
then Z12 min =0.32 mm.
32= A11 min-10.5
A11 min=0.32+10.5=10.82 mm
A11 max =10.82+0.27=11.09mm
A11=11.09-0.27.
) ZA11 = A10 - A11, (rough drilling, operation 005).
ZA11 min = A10 min - A11 max.
The minimum allowance is taken taking into account the drilling depth ZА11 min = 48.29 mm.
29= A10 min - 11.09
A10 min=48.29+11.09=59.38mm
А10max =59.38+0.12=59.5mm
) ZA10 = A9 - A10, (finish turning, operation 005).
ZA10 min = A9 min - A10 max.
Let's calculate ZА10 min. ZА10 min is determined by the errors arising during finishing turning.
Let us assign Rz=0.02 mm, h=0.12 mm, =0.01 mm, =0 mm (installation in the chuck). The value of the allowance is determined by the formula:
ZА10 min = (RZ + h)i-1 + D2Si-1 + e 2i ;
ZA10 min = (0.02 + 0.12) + 0.012+ 02 = 0.15 mm.
then ZА10 min =0.15 mm.
15= A9 min-59.5
A9 min=0.15+59.5=59.65 mm
A9 max =59.65+0.19=59.84mm
) D5 = A12 - A4 + A6
Let's write the system of equations:
D5min = -A4max +A12min +A6min
D5max = -A4min+A12max +A6max
82 = -59.77 + 10.5+A6 min
18 = -59.65 + 10.38+ A6 max
A6 min = 57.09 mm
A6 max = 57.45 mm
TA6=0.36 mm. We assign admission based on economically feasible qualifications. TA6=0.03 mm.
Let's finally write:
A15=57.45h7(-0.03)
The results of calculating the remaining technological dimensions obtained from equations with a closing link - an allowance limited by lowest value are presented in Table 5.5.
Table 5.5. Results of calculations of linear operational dimensions
Equation No. Equations Unknown operational size Smallest allowance Tolerance of unknown operational size Value of unknown operational size Accepted value of operational size 1D5 = A12 - A4 + A6 A12-0.2710.5-0.2710.5-0.272ZA12 = A11 - A12 A1140.2711.09-0.2711, 09-0.273ZA11 = A10 - A11 A1040.1259.5-0.1259.5-0.124ZA10 = A9 - A10 A910.1959.84-0.1959.84-0.195ZA9 = A4 - A9 A420.1960.27- 0.1960.27-0.196ZA8 = A4 - A8 - Z4A840.3355.23-0.3355.23-0.337ZA7 = A5 - A7A540.02118.521-0.02118.52-0.0218ZA6 = A2 - A6 A20 ,50.1957.24-0.1957.24-0.199ZA5 = A1 - A5A10.50.1318.692-0.1318.69-0.1310ZA4 = A3 - A4A310.361.02-0.361.02-0.311ZA3 = Z3 - A3Z320.3061.62-0.3061.62-0.3012ZA2 = Z2 - A2Z220.3057.84-0.3057.84-0.3013ZA1 = Z1 - A1Z120.2119.232-0.2119.23-0.21
Selection of working devices
Considering the accepted type and form of production organization based on the group processing method, it can be stated that it is advisable to use specialized, high-speed, automated, adjustable devices. Self-centering chucks are used in turning operations. All devices must contain in their design a base part (common in the basing scheme for all parts of the group) and replaceable settings or adjustable elements for quick changeover when switching to processing any of the parts of the group. In processing this part, the only device is a turning self-centering three-jaw chuck.
Figure 3
5.5 Calculation of cutting conditions
5.1 Calculation of cutting conditions for turning operation 005 with CNC
Let's calculate cutting modes for semi-finishing of a part - trimming ends, turning cylindrical surfaces (see sketch of the graphic part).
For the semi-finishing stage of processing we accept: cutting tool - contour cutter with a triangular plate with apex angle e=60 0made of hard alloy, tool material - T15K6 fastening - wedge-clamp, with a leading angle c=93 0, with an auxiliary plan angle - c1 =320 .
rear angle c = 60;
front angle - g=100 ;
the shape of the front surface is flat with a chamfer;
radius of rounding of the cutting edge c = 0.03 mm;
radius of the cutter tip - rв =1.0 mm.
For the semi-finishing stage of processing, the feed is selected according to S 0t =0.16 mm/rev.
S 0= S 0T Ks And Ks p Ks d Ks h Ks l Ks n Ks ts Ksj K m ,
Ks And =1.0 - coefficient depending on the instrumental material;
Ks p =1.05 - depending on the method of plate fastening;
Ks d =1.0 - from the cross-section of the cutter holder;
Ks h =1.0 - on the strength of the cutting part;
Ks l =0.8 - from the workpiece installation diagram;
Ks n =1.0 - on the state of the workpiece surface;
Ks ts =0.95 - from the geometric parameters of the cutter;
Ks j =1.0 from the rigidity of the machine;
K sm =1.0 - on the mechanical properties of the material being processed.
S 0= 0.16*1.1*1.0*1.0*1.0*0.8*1.0*0.95*1.0*1.0=0.12 mm/rev
Vt =187 m/min.
The final cutting speed for the semi-finishing stage of processing is determined by the formula:
V= V T Kv And Kv With Kv O Kv j Kv m Kv cKv T Kv and
Kv And - coefficient depending on the instrumental material;
Kv With - from the material machinability group;
Kv O - depending on the type of processing;
Kv j - machine rigidity;
Kv m - on the mechanical properties of the material being processed;
Kv ts - on the geometric parameters of the cutter;
Kv T - on the service life of the cutting part;
Kv and - from the presence of cooling.
V= 187*1.05*0.9*1*1*1*1*1*1=176.7 m/min;
The rotation speed is calculated using the formula:
The calculation results are given in table.
Check calculation of cutting power Npeс, kW
where N T . - table value of power, kN;
The power condition is satisfied.
Table 5.6. Cutting conditions for operation 005. A. Position I.T01
Elements of the cutting modeMachined surfacesT. Æ 118/ Æ 148Æ 118T. Æ 70h8/ Æ 118Æ 70h8T. Æ 50h8/ Æ 70h8Cutting depth t, mm222222 Table feed Sfrom, mm/rev0,160,160,160,160,16Accepted feed So, mm/rev0,120,120,120,120,12Table cutting speed Vt, m/min187187187187187Adjusted cutting speed V, m/min 176.7176.7176.7176.7176.7 Actual frequency spindle rotation nf, rpm 380.22476.89476.89803.91803.91 Accepted spindle rotation speed np, rpm 400500500800800 Actual cutting speed Vf, m/min 185.8185.26185.26175.84175.84 Tabular cutting power Nt, kW -- 3.8-Actual cutting power N, kW---3.4-Minute feed Sm, mm/min648080128128
5.2 Let us perform an analytical calculation of the cutting mode based on the accepted tool life for operation 005 (rough turning Æ 148)
The tool is a contour cutter with a replaceable multifaceted insert made of T15K6 grade hard alloy.
The cutting speed for external longitudinal and transverse turning is calculated using the empirical formula:
where T is the average value of tool life, for single-tool processing it is assumed to be 30-60 minutes, let’s choose the value T = 45 minutes;
Cv, m, x, y - table coefficients (Cv = 340; m = 0.20; x = 0.15; y = 0.45);
t - depth of cut (assumed for rough turning t=4mm);
s - feed (s=1.3 mm/rev);
Кv = Kmv*Kпv*Kиv,
where Kmv is a coefficient that takes into account the influence of the workpiece material (Kmv = 1.0), Kpv is a coefficient that takes into account the influence of the surface condition (Kpv = 1.0), Kpv is a coefficient that takes into account the influence of the tool material (Kpv = 1.0). Кv = 1.
5.3 Calculation of cutting conditions for operation 005 (drilling radial holes Æ36)
Tool - drill R6M5.
We carry out the calculation according to the method specified in. Using the table, we determine the value of drill feed per revolution. So = 0.7 mm/rev.
Cutting speed when drilling:
where T is the average value of tool life, according to the table we select the value T = 70 min;
WITH v , m, q, y - tabular coefficients (C v = 9.8; m = 0.20; q = 0.40; y = 0.50);
D - drill diameter (D = 36 mm);
s - feed (s=0.7 mm/rev);
TO v = K mv *Kпv *K andv ,
where K mv - coefficient taking into account the influence of the workpiece material (K mv =1.0), K pv - coefficient taking into account the influence of surface condition (K pv = 1.0), K pv - coefficient taking into account the influence of the tool material (K pv =1.0). TO v = 1.
6 Technical standardization
6.1 Determination of piece-calculation time for turning operation with CNC 005
The standard piece time for CNC machines is determined by the formula:
where T ts.a. - time of automatic operation of the machine according to the program;
Auxiliary time.
0.1 min - auxiliary time for installing and removing the part;
Auxiliary time associated with the operation includes the time to turn on and off the machine, checking the return of the tool to a given point after processing, installing and removing the shield that protects against splashing with emulsion:
Auxiliary time for control measurements contains five measurements with a caliper and five measurements with a clamp:
=(0.03+0.03+0.03+0.03+0.03)+(0.11+0.11+0.11+0.11+0.11)= 0.6 min.
0.1+0.18+0.6=0.88 min.
We accept that remote control is being carried out at the site.
Calculation of the time of automatic operation of the machine according to the program (Tts.a.) is presented in Table 5.7.
Determination of the main time To is made according to the formula:
where L p.x. - length of the working stroke;
Sm - feed.
Determination of idling time is calculated using the formula:
where L x.x. - length idle speed;
Sхх - idle supply.
Table 5.7. Time of automatic operation of the machine according to the program (installation A)
Coordinates of reference points Increment along the Z axis, ДZ, mm Increment along the X axis, ДX, mm Length of the i-th stroke, mm Minute feed per i-th section, Sм, mm/min Main time of automatic operation of the machine according to the program Т0, min Machine-auxiliary time Тмв, min. Tool Т01 - Contour cutter SI0,010-1-81,31-2484,77100000,0081-20-16,7516,75480 - Boring cutter SI0.010-7-37-75.2583.85100000.0087-8-61061960.638-90-22100000.00029-061061100000.006110-03777.2585.65100000.008 Tool T0 1 - Contour cutterSI0.010-11- 39.73-6475.32100000.007511-120-36361000.3612-039.98100107.69100000.0107 Tool T03 - contour cutter 0-13-81.48-2585.22100000.008514-150-16 161000,1615-1638,48038, 481000.38 16-17 0-24241000.24 17-18 4 041000.0418-0 39 6575.80100000.0075 Tool T04 - Boring cutterSI0.010-19-39-7584.53100000.008419-2 0-600601000,620-210-22100000 - 25420421000.0025 25-26024.524.5100000.0024 26-27-420421000 ,4227-28420421000,4228-29034,534,5100000,003429-30-420421000,4230-31420421000,4231-320-24,524,5100000,002432-33-420421000 ,4233-34420421000.4234-04095103.07100000.0103Total7.330 .18 Automatic cycle time 7.52
For installation B: Tts.a=10.21; =0.1; =0 min. Remote control.
Time for organizational and maintenance workplace, rest and personal needs are given as a percentage of operational time [4, map 16]:
The final rate of piece time is:
Tsh= (7.52+10.21+0.1+0.1)*(1+0.08)=19.35 min.
The standard preparatory and final time for a CNC machine is determined by the formula:
Tpz=Tpz1+Tpz2+Tpz3,
where Тпз1 is the standard time for organizational preparation;
Тпз2 - standard time for setting up a machine, device, tool, software devices, min;
Тпз3 - time limit for trial processing.
The calculation of preparatory and final time is presented in Table 5.8.
Table 5.8. Structure of preparatory and final time
No. Work content Time, min 1. Organizational preparation 9.0 + 3.0 + 2.0 Total Tpz 114.0 Setting up the machine, fixtures, tools, software devices 2. Set the initial processing modes of the machine 0.3 * 3 = 0.93. Install the chuck 4, 04. Install cutting tools 1.0 * 2 = 2.05. Enter the program into the memory of the CNC system 1.0 Total Tpz 210.96. Trial processing The part is accurate (semi-finishing), surfaces are processed to the 11th grade 12 Total Tpz 310 + tt Total preparatory and final time for the batch 36.3 details: Tpz=Tpz1+Tpz2+Tpz3
Tsht.k=Tsht+Tpz=19.35+=19.41min.
6. Metrological support of the technological process
In modern engineering production, control of the geometric parameters of parts during their production is mandatory. The costs of performing control operations significantly affect the cost of mechanical engineering products, and the accuracy of their assessment determines the quality of manufactured products. When performing technical control operations, the principle of uniformity of measurements must be ensured - measurement results must be expressed in legal units and the measurement error must be known with the specified probability. Control must be objective and reliable.
The type of production - serial - determines the form of control - selective statistical control of the parameters specified in the drawing. The sample size is 1/10 of the batch size.
Universal measuring instruments are widely used in all types of production due to their low cost.
Chamfer inspection is carried out using special measuring tools: templates. The measurement method is passive, contact, direct portable measuring instrument. We control the outer cylindrical surface with an indicator bracket on the stand SI-100 GOST 11098.
We control the outer end surfaces at the rough and semi-finish stages using ShTs-11 GOST 166, and at the finishing and high-precision stages using a special template.
We control roughness at the roughing and semi-finishing stages using GOST 9378 roughness samples. The measurement method is passive contact comparative, with a portable measuring instrument. Roughness control at the finishing stage is carried out using an MII-10 interferometer. The measurement method is passive contact, portable measuring instrument.
Final control is carried out by the technical control department at the enterprise.
7. Safety of the technological system
Development of technological documentation, organization and implementation of technological processes must comply with the requirements of GOST 3.1102. Production equipment used in cutting must comply with the requirements of GOST 12.2.003 and GOST 12.2.009. Devices for cutting processing must comply with the requirements of GOST 12.2.029. The maximum permissible concentration of substances formed during cutting must not exceed the values established by GOST 12.1.005 and regulatory documents Ministry of Health of Russia.
2 Requirements for technological processes
Safety requirements for the cutting process must be set out in technological documents in accordance with GOST 3.1120. Installation of workpieces and removal of finished parts during operation of the equipment is permitted when special positioning devices are used to ensure the safety of workers.
3 Requirements for storage and transportation of raw materials, workpieces, semi-finished products, coolant, finished parts, production waste and tools
Safety requirements for transportation, storage and operation of abrasive and CBN tools in accordance with GOST 12.3.028.
Containers for transportation and storage of parts, workpieces and production waste in accordance with GOST 14.861, GOST 19822 and GOST 12.3.020.
Loading and unloading of goods - in accordance with GOST 12.3.009, movement of goods - in accordance with GOST 12.3.020.
4 Monitoring compliance with safety requirements
The completeness of safety requirements must be monitored at all stages of technological process development.
Monitoring noise parameters at workplaces - in accordance with GOST 12.1.050.
In this course project, the volume of output was calculated and the type of production was determined. The correctness of the drawing was analyzed in terms of compliance with current standards. The route for processing the part was designed, equipment, cutting tools and fixtures were selected. The operational dimensions and workpiece dimensions were calculated. Cutting modes and time standards for turning operations are determined. Issues of metrological support and safety precautions are considered.
Literature
- Technologist's guide to automatic lines. /A.G. Kosilova, A.G. Lykov, O.M. Deev et al.; Ed. A.G. Kosilova. - M,: Mechanical Engineering, 1982.
- Handbook of mechanical engineering technologist./ Ed. A.G. Kosilova and R.K. Meshcheryakova. - M.: Mechanical Engineering, 1985.
- Timofeev V.N. Calculation of linear operational dimensions and their rational placement. Study guide. Gorky: GPI, 1978.
- Gorbatsevich A.F., Shkred V.A. Course design in mechanical engineering technology: [Tutorial for mechanical engineering. specialist. universities]. - Mn.: Higher. school, 1983.
- Metal cutting modes: Handbook / Ed. Yu.V. Baranovsky. - M.: Mechanical Engineering, 1995.
- Unified components and parts of modular machines and automatic lines. Directory catalogue.
- General machine-building standards for time and cutting modes for rationing work in mass production. In 2 parts. - M.: Economics, 1990
- Ordinartsev I.A., Filipov G.V., Shevchenko A.N. Toolmaker's Handbook./ Under the general title. ed. I.A. Ordinartseva - L.: Mechanical Engineering, 1987.
- GOST 16085-80 Gauges for monitoring the location of surfaces.
- GOST 14.202 - 73. Rules for ensuring manufacturability of product designs. - M. Standards Publishing House, 1974.
- Zazersky V.I. Zholnerchik S.I. Technology of processing parts on computer-controlled machines. - L. Mechanical Engineering, 1985.
- Orlov P.I. Basics of design. Book 1,2,3.- M. Mechanical Engineering, 1977.
- Handbook of machine-building plant controller. Tolerances, fits, linear measurements. Ed. A.I. Yakusheva. Ed. 3rd-M. Mechanical Engineering, 1985.
- Calculation of allowances: Method. instructions for implementation practical work and sections in course and diploma projects for students of mechanical engineering specialties of all forms of study/NSTU; Comp.: D.S. Pakhomov, N, Novgorod, 2001. 24 p.
- Metelev B.A., Kulikova E.A., Tudakova N.M. Mechanical engineering technology, Parts 1,2: Complex of educational and methodological materials; Nizhny Novgorod State Technical University, Nizhny Novgorod, 2007 - 104 p.
16. Metelev B.A. Basic provisions for the formation of processing on metal cutting machine: textbook / B.A. Metelev. - NSTU. Nizhny Novgorod, 1998
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Part "Adapter"
ID: 92158Upload date: February 24, 2013
Salesman: Hautamyak ( Write if you have any questions)
Type of work: Diploma and related
File formats: T-Flex CAD, Microsoft Word
Passed at the educational institution: Ri(F)MGOU
Description:
The “Adapter” part is used in the RT 265 deep drilling machine, which is produced by JSC RSZ.
It is designed to attach the cutting tool to the “Stem”, which is a fixed axis fixed in the tailstock of the machine.
Structurally, the “Adapter” is a body of revolution and has a rectangular three-way internal thread for fastening the cutting tool, as well as a rectangular external thread for connecting to the “Stem”. The through hole in the “Adapter” serves:
for removing chips and coolant from the cutting zone when drilling blind holes;
for supplying coolant to the cutting zone when drilling through holes.
The use, specifically, of a three-start thread is due to the fact that during the processing process, in order to quickly change tools, it is necessary to quickly unscrew one tool and wrap the other into the body of the “Adapter”.
The blank for the “Adapter” part is rolled steel ATs45 TU14-1-3283-81.
CONTENT
sheet
Introduction 5
1 Analytical part 6
1.1 Purpose and design of part 6
1.2 Manufacturability analysis 7
1.3 Physical and mechanical properties of the material of the part 8
1.4 Analysis of the basic technological process 10
2 Technological part 11
2.1 Determining the type of production, calculating the size of the launch batch 11
2.2 Choosing a method for obtaining a workpiece 12
2.3 Calculation of minimum allowances for processing 13
2.4 Calculation of the weight accuracy coefficient 17
2.5 Economic justification for the choice of workpiece 18
2.6 Design version of the technological process 20
2.6.1 General 20
2.6.2 Order and sequence of execution of TP 20
2.6.3 Route of the new technological process 20
2.6.4 Selection of equipment, description of technological capabilities
and technical characteristics of machines 21
2.7 Justification of the basing method 25
2.8 Selection of fastening devices 25
2.9 Selecting cutting tools 26
2.10 Calculation of cutting conditions 27
2.11 Calculation of piece and piece-calculation time 31
2.12 Special question on mechanical engineering technology 34
3 Design part 43
3.1 Description of the fastening device 43
3.2 Calculation of fastening devices 44
3.3 Description of the cutting tool 45
3.4 Description of the control device 48
4. Calculation of the mechanical shop 51
4.1 Calculation of required workshop equipment 51
4.2 Determination of the production area of the workshop 52
4.3 Determining the required number of workers 54
4.4 Choice constructive solution industrial building 55
4.5 Design of service premises 56
5. Safety and environmental friendliness of design solutions 58
5.1 Characteristics of the object of analysis 58
5.2 Analysis of the potential hazard of the designed site
machine shop for workers and environment 59
5.2.1 Analysis of potential hazards and hazardous work conditions
factors 59
5.2.2 Analysis of the workshop’s environmental impact 61
5.2.3 Possibility analysis
emergency situations 62
5.3 Classification of premises and production 63
5.4 Ensuring safe and sanitary
hygienic working conditions in workshop 64
5.4.1 Safety measures and equipment 64
5.4.1.1 Automation of production processes 64
5.4.1.2 Equipment location 64
5.4.1.3 Fencing of hazardous areas, prohibited areas,
safety and locking devices 65
5.4.1.4 Ensuring electrical safety 66
5.4.1.5 Waste disposal in workshop 66
5.4.2 Activities and means for production
sanitation 67
5.4.2.1 Microclimate, ventilation and heating 67
5.4.2.2 Industrial lighting 68
5.4.2.3 Protection from noise and vibration 69
5.4.2.4 Auxiliary sanitary facilities
premises and their arrangement 70
5.4.2.5 Tools personal protection 71
5.5 Measures and means to protect the environment
environment from the impact of the designed mechanical shop 72
5.5.1 Solid waste disposal 72
5.5.2 Purification of atmospheric exhaust gases 72
5.5.3 Cleaning waste water 73
5.6 Measures and means to ensure
security in emergency situations 73
5.6.1 Ensuring fire safety 73
5.6.1.1 Fire prevention system 73
5.6.1.2 System fire protection 74
5.6.2 Providing lightning protection 76
5.7. Support Engineering
labor safety and environmental protection 76
5.7.1 Calculation of total illumination 76
5.7.2 Calculation of piece noise absorbers 78
5.7.3 Calculation of cyclone 80
6. Organizational part 83
6.1 Description automated system
project site 83
6.2 Description of automated transport and warehouse
systems of the designed site 84
7. Economic part 86
7.1 Initial data 86
7.2 Calculation of capital investments in fixed assets 87
7.3 Material costs 90
7.4 Design organizational structure workshop management 91
7.5 Calculation of the annual fund wages working 92
7.6 Estimating indirect and shop costs 92
7.6.1 Cost estimate for maintenance and operation
equipment 92
7.6.2 Estimate of general shop expenses 99
7.6.3 Distribution of costs for maintenance and operation
equipment and public costs for the cost of products 104
7.6.4 Cost estimate for production 104
7.6.4.1 Cost calculation of the kit 104
7.6.4.2 Calculation of unit costs 105
7.7 Resulting part 105
Conclusion 108
References 110
Applications
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