Axis in the mechanism. Shafts and axles general information

To create a quality technological process manufacturing a part, it is necessary to carefully study its design and purpose in the machine.

The technological design of the part is shown in the figure.

The part is a cylindrical axis. The highest demands on the accuracy of shape and location, as well as roughness, are imposed on the surfaces of the journals of the axle, designed to fit the bearings. So the accuracy of the necks for bearings must correspond to the 7th grade. High requirements for the accuracy of the location of these axle journals relative to each other follow from the operating conditions of the axle.

All axle journals are surfaces of rotation of relatively high precision. This determines the expediency of using turning operations only for their preliminary processing, and the 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 setup or, in extreme cases, on the same bases.

Axes of this design are widely used in mechanical engineering.

Axes are designed to transmit torque and mount various parts and mechanisms on them. They are a combination of smooth landing and non-landing surfaces, as well as transitional surfaces.

The technical requirements for the axles are characterized by the following data. The diametrical dimensions of the landing necks are performed according to IT7, IT6, other necks according to IT10, IT11.

The design of the axle, its dimensions and rigidity, technical requirements, production program are the main factors that determine 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 of a circular cross section of various diameters and lengths. There is a thread on the axle. The axis length is 112 mm, the maximum diameter is 75 mm and the minimum diameter is 20 mm.

Based on the design purpose of the part in the machine, all surfaces of this part can be divided into 2 groups:

main or working surfaces;

free or non-working surfaces.

Almost all surfaces of the axis are considered basic because they are mated 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 the part processing and the degree of roughness indicated in the drawing.

It can be noted that the design of the part fully meets its official purpose. But the principle of manufacturability of the design is not only to meet the operational requirements, but also the requirements of 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, as it contains simple surface profiles, its processing does not require specially designed fixtures and machines. The surfaces of the axis are processed on turning, drilling and grinding machines. The required dimensional accuracy and surface roughness are achieved by a relatively small set of simple operations, as well as a set of standard cutters and grinding wheels.

The manufacture of a part is labor-intensive, which is associated primarily with the provision specifications the work of the part, the necessary dimensional accuracy, the roughness of the working surfaces.

So, the part is manufacturable in design and processing methods.

Technological drawing of the part<<Ось>>.

APPLIED MECHANICS AND

DESIGN BASICS

Lecture 8

SHAFTS AND AXES

A.M. SINOTIN

Department of Technology and Automation of Production

Shafts and axles General information

Gears, pulleys, sprockets and other rotating machine parts are mounted on shafts or axles.

Shaft designed to support the parts sitting on it and to transmit torque. During operation, the shaft experiences bending and torsion, and in some cases additional tension and compression.

Axis- a part designed only to support the parts sitting on it. Unlike a shaft, an axle does not transmit torque and therefore does not experience torsion. The axles can be fixed or rotate with the parts mounted on them.

Variety of shafts and axles

According to the geometric shape, the shafts are divided into straight (Figure 1), cranked and flexible.

1 - spike; 2 - neck; 3 - bearing

Picture 1 - Straight stepped shaft

Crankshafts and flexible shafts are special parts and are not covered in this course. Axes are usually made straight. By design, straight shafts and axles differ little from each other.

The length of straight shafts and axles can be smooth or stepped. The formation of steps is associated with different tensions of individual sections, as well as manufacturing conditions and ease of assembly.

According to the type of section, shafts and axles are solid and hollow. A hollow section is used to reduce mass or to fit inside another part.

Structural elements of shafts and axles

1 pins. The sections of the shaft or axis lying in the supports are called trunnions. They are divided into spikes, necks and heels.

Thorn called a trunnion, located at the end of a shaft or axis and transmitting a predominantly radial load (Fig. 1).

Figure 2 - Heels

Sheika called a trunnion located in the middle part of the shaft or axis. Bearings serve as supports for the necks.

Spikes and necks can be cylindrical, conical and spherical in shape. In most cases, cylindrical pins are used (Fig. 1).

Fifth called a trunnion that transmits the axial load (Figure 2). Heels serve as supports for the heels. Heels in shape can be solid (Figure 2, a), annular (Figure 2, b) and comb-shaped (Figure 2, c). Comb heels are rarely used.

2 Landing surfaces. The seating surfaces of the shafts and axles for the hubs of the mounted parts are cylindrical (Figure 1) and less often conical. During press fits, the diameter of these surfaces is taken to be approximately 5% larger than the diameter of neighboring sections for ease of pressing (Figure 1). The diameters of the seating surfaces are selected in accordance with GOST 6336-69, and the diameters for rolling bearings are selected in accordance with GOSTs for bearings.

3 transition areas. Transition sections between two stages of shafts or axles perform:

With a groove with a rounding for the exit of the grinding wheel in accordance with GOST 8820-69 (Figure 3, a). These grooves increase the stress concentration and are therefore recommended for end sections where the bending moments are small;

Figure 3 - Transitional sections of the shaft

with a fillet * of constant radius according to GOST 10948-64 (Figure 3, b);

With a fillet of variable radius (Figure 3, c), which helps to reduce stress concentration, and therefore is used on heavily loaded sections of shafts and axles.

Effective means for reducing the stress concentration in the transition areas are turning relief grooves (Figure 4, a), increasing the fillet radii, drilling in large diameter steps (Figure 4, b).

Picture 4 - Ways to increase the fatigue strength of the shafts

1.1 Service purpose and technical characteristics of the part

To draw up a high-quality technological process for manufacturing a part, it is necessary to carefully study its design and purpose in the machine.

Axes of this design are widely used in mechanical engineering.

Axes are designed to transmit torque and mount various parts and mechanisms on them. They are a combination of smooth landing and non-landing surfaces, as well as transitional surfaces.

The design of the axle, its dimensions and rigidity, technical requirements, production program are the main factors that determine the manufacturing technology and the equipment used.

Based on the design purpose of the part in the machine, all surfaces of this part can be divided into 2 groups:

main or working surfaces;

free or non-working surfaces.

The manufacture of the part is labor-intensive, which is primarily due to the provision of the technical conditions for the work of the part, the necessary dimensional accuracy, and the roughness of the working surfaces.

So, the part is manufacturable 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. It is 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
FROM	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's stop a little mechanical properties rolled products and forgings required for further analysis, which we also summarize in Table 1.2.

Table 1.2

Here are 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 - 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

In the task for the course project, the annual program for the production of a product in the amount of 7000 pieces is indicated. According to the source formula, we determine the annual program for the production of parts in pieces, taking into account spare parts and possible losses:

where P is the annual program for the production of products, pieces;

P 1 - annual program for the manufacture of parts, pcs. (accept 8000 pieces);

b - the number of additionally manufactured parts for spare parts and to compensate for possible losses, in percent. You can take b=5-7;

m - the number of parts of this item in the product (accept 1 pc.).

PCS.

The size of the production program in natural quantitative terms determines the type of production and has a decisive influence on the nature of the construction of the technological process, on the choice of equipment and tooling, and on the organization of production.

In mechanical engineering, there are three main types of production:

Single or individual production;

Mass production;

Mass production.

Based on the release program, we can conclude that in this case we have mass production. At serial production products are manufactured in batches, or in series, periodically repeating.

Depending on the size of batches or series, there are three types of mass production for medium-sized machines:

Small-scale production with the number of products in a series of up to 25 pieces;

Medium-scale production with the number of products in a series of 25-200 pieces;

Large-scale production with the number of products in a series of more than 200 pieces;

A characteristic feature of serial production is that the production of products is carried out 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 the manufacture of parts, pieces;

L is the number of days for which it is necessary to have a stock of parts in stock to ensure assembly (we accept L = 10);

F is the number of working days in a year. You can take F=240.

PCS.

Knowing the annual output of parts, we determine that this production refers to large-scale production (5000 - 50000 pieces).

In serial production, each operation of the technological process is assigned to a specific workplace. At most workplaces, several operations are performed, periodically repeated.

1.3 Selecting the way to obtain the workpiece

The method of obtaining the initial blanks of machine parts is determined by the design of the part, the volume of output and the production plan, as well as the economics of manufacturing. Initially, from the whole variety of methods for obtaining initial workpieces, several methods are selected that technologically provide the possibility of obtaining a workpiece of a given part and allow the configuration of the initial workpiece to be as close as possible to the configuration finished part. To choose a workpiece means to choose a method for obtaining it, outline allowances for processing each surface, calculate dimensions and indicate 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 decision on the choice of workpieces, if from the point of view technical requirements and possibilities, their various types are applicable, can only be obtained as a result of technical and economic calculations by comparing the options for the cost 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 structural shapes and sizes of parts, and the production program. Preference should be given to the workpiece, characterized by the best use of metal and lower cost.

Let's take two methods for obtaining blanks and after analyzing each we will choose the desired method for obtaining blanks:

1) receiving a blank from a rolled product

2) obtaining a workpiece by stamping.

You should choose the most "successful" method for obtaining the workpiece by analytical calculation. Let's compare the options for the minimum value of the reduced costs for the manufacture of the part.

If the workpiece is made from rolled products, then the cost of the workpiece is determined by the weight of the rolled product required to manufacture the part and the weight of the chips. The cost of a rolled billet is determined by the following formula:

where Q is the mass of the workpiece, kg;

S is the price of 1 kg of workpiece material, rub.;

q is the mass of the finished part, kg;

Q = 3.78 kg; S = 115 rubles; q = 0.8 kg; S out \u003d 14.4 kg.

Substitute the initial data in the formula:

Consider the option of obtaining a workpiece by stamping on the GCF. 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 accuracy class of stampings;

K C - coefficient depending on the group of complexity of stampings;

K B - coefficient depending on the mass of forgings;

K M - coefficient depending on the brand of stamping material;

K P - coefficient depending on the annual program for the production of stampings;

Q is the mass of the workpiece, kg;

q is the mass of the finished part, kg;

S waste - the price of 1 ton of waste, rub.

C i = 315 rubles; Q = 1.25 kg; K T = 1; K C = 0.84; K B \u003d 1; K M = 1; K P \u003d 1;

q = 0.8 kg; S out \u003d 14.4 kg.

The economic effect for comparing the methods of obtaining blanks, in which the technological process of machining does not change, can be calculated by the formula:

where S E1, S E2 - the cost of the compared blanks, rub.;

N – annual program, pcs.

We define:

From the results obtained, it can be seen that the option of obtaining a workpiece by stamping is economically viable.

Production of blanks by stamping on various types equipment is a progressive method, as it significantly reduces the allowances for machining in comparison with obtaining a workpiece from rolled products, and is also characterized by a higher degree of accuracy and higher productivity. The stamping process also densifies the material and creates a 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 term paper, 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 of its production have the most direct and very significant influence on the nature of the construction of the technological process of manufacturing the part, since, depending on the chosen method for obtaining the workpiece, the amount of allowance for processing the part can fluctuate significantly and, therefore, it is not the set of methods that changes, used for surface treatment.

1.4 Purpose of methods and processing steps

The choice of processing method is influenced by the following factors that must be considered:

the shape and size of the part;

accuracy of processing and cleanliness of surfaces of parts;

economic feasibility of the chosen 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 the part with the designation of the layers removed during machining

All axle surfaces have rather high requirements for roughness. The turning of surfaces A, B, C, D, E, F, H, I, K is divided into two operations: rough (preliminary) and finishing (final) turning. When rough turning, we remove most of the allowance; processing is carried out with a large depth of cut and a large feed. The scheme that provides the shortest processing time is the most advantageous. When finishing turning, we remove a small part of the allowance, and the order of surface treatment is preserved.

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 the G and I surfaces, it is necessary to apply fine grinding, in which the accuracy of processing the outer cylindrical surfaces reaches the third class, and the surface roughness reaches 6-10 classes.

For greater clarity, we will schematically write down the selected processing methods for each surface of the part:

A: rough turning, finishing turning;

B: rough turning, finishing turning, threading;

B: rough turning, finishing turning;

G: rough turning, fine turning, fine grinding;

D: rough turning, finishing turning;

E: rough turning, finishing turning;

Zh: drilling, countersinking, deployment;

Z: rough turning, finishing turning;

And: rough turning, fine turning, fine grinding;

K: rough turning, finishing turning;

L: drilling, countersinking;

M: drilling, countersinking;

Now you can proceed to the next stage of the course work related to the choice of technical bases.

1.5 Selection of bases and sequence of processing

The workpiece of the part in the process of processing must take and maintain a certain position relative to the parts of the machine or fixture during the entire processing time. To do this, it is necessary to exclude the possibility of three rectilinear movements of 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 the part 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 dimensions of the workpiece, these points can be located on the coordinate surface in various ways.

It is recommended to choose engineering 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, the basing of the part is carried out according to the following schemes.

Figure 1.2 Scheme of setting the 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 about the OX axis and the 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 accuracy of processing and surface cleanliness, sets of processing methods were selected for each surface of the shaft. We can determine the sequence of surface treatment.

Figure 1.4 Sketch of the part with the designation of surfaces

1. Turning operation. The workpiece is installed on the surface 4 in

self-centering 3-jaw chuck with end stop 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 end stop 5 for fine turning of end face 9, face 8, face 7, face 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 an emphasis on end 7 for fine turning of end 1, surface 2, end 3, surface 4, end 5, chamfers 14, 15 and grooves 17, 18.

5. Turning operation. The workpiece is installed in a self-centering 3-jaw chuck along surface 8 with an emphasis on the end face 7 for drilling and countersinking surface 10, threading on surface 2.

6. Drilling operation. We set the part in a vice on surface 6 with an emphasis on the end face 9 for drilling, countersinking and reaming surface 11, drilling and countersinking surfaces 12 and 13.

7. Grinding operation. The part is installed on surface 4 in a self-centering 3-jaw chuck with a stop on the end face 5 for grinding surface 8.

8. Grinding operation. The part is installed on the surface 8 in a self-centering 3-jaw chuck with an emphasis on the end face 7 for grinding the 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 - fine turning;

surface 8 - fine turning;

surface 7 - fine turning;

surface 6 - fine turning;

surface 16 - chamfer;

surface 19 - sharpen a groove;

surface 1 – fine turning;

surface 2 – fine turning;

surface 3 – fine turning;

surface 4 – fine turning;

surface 5 - fine turning;

surface 14 - chamfer;

surface 15 - chamfer;

surface 17 - sharpen a groove;

surface 18 - sharpen the groove;

surface 10 - drilling, countersinking;

surface 2 - threading;

surface 11 - drilling, reaming, reaming;

surface 12, 13 - drilling, countersinking;

surface 8 - fine grinding;

surface 4 - fine grinding;

As you can see, the surface treatment of the workpiece is carried out in order from coarser methods to more accurate ones. 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 is an axis and belongs to the bodies of revolution. We process the workpiece obtained by stamping. When processing, we use the following operations.

010. Turning.

1. grind surface 8, cut end 9;

2. Turn surface 6, trim end 7

Cutter material: CT25.

Coolant brand: 5% emulsion.

015. Turning.

Processing is carried out on a turret lathe model 1P365.

1. grind surface 2, cut end 1;

2. grind surface 4, cut end 3;

3. cut end 5.

Cutter material: CT25.

Coolant brand: 5% emulsion.

The part is based in a three-jaw chuck.

As a measuring tool we use a bracket.

020. Turning.

Processing is carried out on a turret lathe model 1P365.

1. grind surfaces 8, 19, cut end 9;

2. grind surfaces 6, cut end 7;

3. chamfer 16.

Cutter material: CT25.

Coolant brand: 5% emulsion.

The part is based in a three-jaw chuck.

As a measuring tool we use a bracket.

025. Turning.

Processing is carried out on a turret lathe model 1P365.

1. grind surfaces 2, 17, cut end 1;

2. grind surfaces 4, 18, cut end 3;

3. cut end 5;

4. chamfer 15.

Cutter material: CT25.

Coolant brand: 5% emulsion.

The part is based in a three-jaw chuck.

As a measuring tool we use a bracket.

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 brand: 5% emulsion.

The part is based in a three-jaw chuck.

035. Drilling

Processing is carried out on a coordinate drilling machine 2550F2.

1. drill, countersink 4 stepped holes Ø9 - surface 12 and Ø14 - surface 13;

2. drill, countersink, ream hole Ø8 – surface 11;

Drill material: R6M5.

Coolant brand: 5% emulsion.

The part is based in a vise.

We use a caliber as a measuring tool.

040. Sanding

1. sanding the surface 8.

The part is based in a three-jaw chuck.

As a measuring tool we use a bracket.

045. Sanding

Processing is carried out on a circular grinding machine 3T160.

1. sanding 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.

As a measuring tool we use a bracket.

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 the surfaces, the absence of nicks, the blunting of sharp edges. The control table is used.

1.7 Selection of equipment, tooling, cutting and measuring tools

axis workpiece cutting processing

The choice of machine equipment is one of the most important tasks in the development of the technological process of machining the workpiece. The performance of the part manufacturing depends on its correct choice. economic use production areas, mechanization and automation of manual labor, electricity and, as a result, the cost of the product.

Depending on the volume of production of products, machines are selected according to the degree of specialization and high productivity, as well as machines with a numerical program management(CNC).

When developing a technological process for the machining of a workpiece, it is necessary to choose the right devices that should help increase labor productivity, processing accuracy, improve working conditions, eliminate preliminary marking of the workpiece and align them when installed on the machine.

The use of machine tools and auxiliary tools in the processing of workpieces provides a number of advantages:

improves the quality and accuracy of processing parts;

reduces the complexity of processing workpieces due to a sharp decrease in the time spent on installation, alignment and fixing;

expands the technological capabilities of machine tools;

creates the possibility of simultaneous processing of several workpieces fixed in a common fixture.

When developing a technological process for the machining of a workpiece, the choice of a cutting tool, its type, design and dimensions is largely determined by the processing methods, the properties of the material being machined, the required machining accuracy and the quality of the machined surface of the workpiece.

When choosing a cutting tool, one should strive to adopt a standard tool, but, when appropriate, a special, combined, shaped tool should be used, allowing the processing of several surfaces to be combined.

The correct choice of the cutting part of the tool has great importance to improve productivity and reduce processing costs.

When designing a workpiece machining process for inter-operational 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-measuring tool or control-measuring fixture should be used.

The control method should help to increase the productivity of the inspector and the machine operator, create conditions for improving the quality of products and reducing their cost. In single and serial production, a universal measuring tool is usually used (caliper, depth gauge, micrometer, goniometer, indicator, etc.)

In mass and large-scale production, it is recommended to use limit gauges (staples, plugs, templates, etc.) and active control methods, which are widely used in many branches of engineering.

1.8 Calculation of operating dimensions

Operational refers to the size affixed to the operational sketch and characterizing the size of the machined surface or the relative position of the machined surfaces, lines or points of the part. The calculation of operating dimensions is reduced to the task of correctly determining the value of the operating allowance and the value of the operating tolerance, taking into account the features of the developed technology.

Long operating dimensions are understood as dimensions that characterize the processing of surfaces with a one-sided allowance, as well as dimensions between axes and lines. The 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 statement of calculation of operating sizes.

On the processing scheme (Figure 1.5), we place a sketch of the part indicating all the surfaces of a given geometric structure that occur during processing from the workpiece to the finished part. At the top of the sketch, all long drawing dimensions are indicated, drawing dimensions with tolerances (C), and at the bottom, all operating allowances (1z2, 2z3, ..., 13z14). Under the sketch in the processing table, dimension lines are indicated that characterize all dimensions of the workpiece, oriented with one-sided arrows, so that not a single arrow fits one of the surfaces of the workpiece, and only one arrow fits the rest of the surfaces. The following are dimension lines that characterize the dimensions of machining. Operating dimensions are oriented in the direction of the processed surfaces.

Figure 1.5 Scheme of part processing

On the graph of the initial structures connecting surfaces 1 and 2 with wavy edges characterizing the size of the allowance 1z2, surfaces 3 and 4 with additional edges characterizing the size of the allowance 3z4, etc. And we also draw thick edges of drawing sizes 2s13, 4s6, etc.

Figure 1.6 Graph of initial structures

top of the graph. Describes the surface of a part. The number in the circle indicates the number of the surface on the processing scheme.

Graph edge. Characterizes the type of connections between surfaces.

"z" - Corresponds to the value of the operating allowance, and "c" - to the drawing size.

Based on the developed processing scheme, a graph of arbitrary structures is built. The construction of the derived tree starts from the surface of the workpiece, to which no arrows are drawn in the processing scheme. 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 the arrows and the numbers of those surfaces to which the indicated dimensions are drawn. Similarly, we complete the graph according to the processing scheme.

Figure 1.7 Graph of derived structures

top of the graph. Describes the surface of a part.

Graph edge. The component link of the dimensional chain corresponds to the operational size or the size of the workpiece.

Graph edge. The closing link of the dimensional chain corresponds to the drawing size.

Graph edge. The closing link of the dimensional chain corresponds to the operating allowance.

On all edges of the graph we put down a sign (“+” or “-”), guided by the following rule: if the edge of the graph enters the vertex with a large number with its arrow, then we put the sign “+” on this edge, if the edge of the graph enters the vertex with its arrow with a lower number, then we put the “-” sign on this edge (Figure 1.8). We take into account that we do not know the operating dimensions, and according to the processing scheme (Figure 1.5), we determine approximately the value of the operating size or the size of the workpiece, using for this purpose the drawing dimensions and the minimum operating allowances, which are the sum of the microroughness values (Rz), the depth of the deformation layer (T) and spatial deviation (Δpr) obtained in the previous operation.

Column 1. In an arbitrary sequence, we rewrite all drawing dimensions and allowances.

Column 2. We indicate the numbers of operations in the sequence of their execution according to route technology.

Column 3. Specify the name of the operations.

Column 4. We indicate the type of machine and its model.

Column 5. We place simplified sketches in one unchanged position for each operation, indicating the surfaces to be processed according to the route technology. Surfaces are numbered in accordance with the processing scheme (Figure 1.5).

Column 6. For each surface processed at this operation, we indicate the operating size.

Column 7. We do not perform heat treatment of the part at this operation, so we leave the column blank.

Column 8. It is filled in in exceptional cases, when the choice of the measuring base is limited by the conditions for the convenience of controlling the operational size. In our case, the graph remains free.

Column 9. Specify possible options surfaces that can be used as technological bases, taking into account the recommendations given in.

The choice 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 according to the graph of the initial structures.

After choosing the bases and operating dimensions, we proceed to the calculation of nominal values and the choice of tolerances for operating dimensions.

The calculation of long operating dimensions is based on the results of work on optimizing the structure of operating dimensions and is carried out in accordance with the sequence of work. The preparation of the initial data for calculating the operating sizes is carried out by filling in the columns

13-17 maps for choosing bases and calculating operational sizes.

Column 13. To close the links of dimensional chains, which are drawing dimensions, we write down the minimum values \u200b\u200bof these dimensions. To close the links, which are operational allowances, we indicate the value of the minimum allowance, which is determined by the formula:

z min \u003d Rz + T,

where Rz is the height of the irregularities obtained in the previous operation;

T is the depth of the defective layer formed during the previous operation.

The values of Rz and T are determined from the tables.

Column 14. For the closing links of dimensional chains, which are drawing dimensions, we write down the maximum values of these dimensions. The maximum values of the allowances are not yet put down.

Columns 15, 16. If the tolerance for the desired operating size will have a “-” sign, then in column 15 we put the number 1, if “+”, then in column 16 we put the number 2.

Column 17. We put down approximately the values \u200b\u200bof the determined operating dimensions, use the equations of dimensional chains from column 11.

1. 9A8 \u003d 8c9 \u003d 12 mm;

2. 9A5 = 3s9 - 3s5 = 88 - 15 = 73 mm;

3. 9A3 = 3s9 = 88 mm;

4. 7A9 \u003d 7z8 + 9A8 \u003d 0.2 + 12 \u003d 12mm;

5. 7A12 \u003d 3s12 + 7A9 - 9A3 \u003d 112 + 12 - 88 \u003d 36 mm;

6. 10A7 \u003d 7A9 + 9z10 \u003d 12 + 0.2 \u003d 12 mm;

7. 10A4 \u003d 10A7 - 7A9 + 9A5 + 4z5 \u003d 12 - 12 + 73 + 0.2 \u003d 73 mm;

8. 10A2 \u003d 10A7 - 7A9 + 9A3 + 2z3 \u003d 12 - 12 + 88 + 0.2 \u003d 88 mm;

9. 6A10 \u003d 10A7 + 6z7 \u003d 12 + 0.2 \u003d 12 mm;

10. 6A13 \u003d 6A10 - 10A7 + 7A12 + 12z13 \u003d 12 - 12 + 36 + 0.2 \u003d 36 mm;

11. 1A6 \u003d 10A2 - 6A10 + 1z2 \u003d 88 - 12 + 0.5 \u003d 77 mm;

12. 1A11 \u003d 10z11 + 1A6 + 6A10 \u003d 0.2 + 77 + 12 \u003d 89 mm;

13. 1A14 = 13z14 + 1A6 + 6A13 = 0.5 + 77 + 36 = 114 mm.

Column 18. We put down the values of tolerances for operational dimensions adopted according to the accuracy table 7, taking into account the recommendations set out in. After setting the tolerances in column 18, you can determine the maximum allowance values and put them in column 14.

The value of ∆z is determined from the equations in column 11 as the sum of the tolerances for the operating dimensions that make up the dimensional chain.

Column 19. In this column, the nominal values \u200b\u200bof the operating dimensions must be entered.

The essence of the method for calculating the nominal values of operating dimensions is reduced to solving the equations of dimensional chains recorded in column 11.

1. 8c9 = 9A89A8 =

2. 3s9 = 9A39A3 =

3. 3s5 = 3s9 - 9A5

9A5 \u003d 3s9 - 3s5 \u003d

We accept: 9А5 = 73 -0.74

3s5 =

4.9z10 = 10A7 - 7A9

10A7 = 7A9 + 9z10 =

We accept: 10А7 = 13.5 -0.43 (correction + 0.17)

9z10=

5. 4z5 \u003d 10A4 - 10A7 + 7A9 - 9A5

10A4 = 10A7 - 7A9 + 9A5 + 4z5 =

We accept: 10А4 = 76.2 -0.74 (correction + 0.17)

4z5=

6. 2z3 \u003d 10A2 - 10A7 + 7A9 - 9A3

10A2 = 10A7 - 7A9 + 9A3 + 2z3 =

We accept: 10A2 = 91.2 -0.87 (correction + 0.04)

2z3 =

7. 7z8 \u003d 7A9 - 9A8

7A9 = 7z8 + 9A8 =

We accept: 7А9 = 12.7 -0.43 (correction: + 0.07)

7z8=

8. 3s12 \u003d 7A12 - 7A9 + 9A3

7A12 \u003d 3s12 + 7A9 - 9A3 \u003d

We accept: 7А12 = 36.7 -0.62

3s12=

9.6z7 = 6A10 - 10A7

6A10 = 10A7 + 6z7 =

We accept: 6А10 = 14.5 -0.43 (correction + 0.07)

6z7=

10.12z13 = 6A13 - 6A10 + 10A7 - 7A12

6A13 = 6A10 - 10A7 + 7A12 + 12z13 =

We accept: 6А13 = 39.9 -0.62 (correction + 0.09)

12z13=

11. 1z2 \u003d 6A10 - 10A2 + 1A6

1A6 \u003d 10A2 - 6A10 + 1z2 \u003d

We accept: 1А6 = 78.4 -0.74 (correction + 0.03)

1z2 =

12.13z14 = 1A14 - 1A6 - 6A13

1A14=13z14+1A6+6A13=

We accept: 1A14 = 119.7 -0.87 (correction + 0.03)

13z14=

13. 10z11 = 1A11 - 1A6 - 6A10

1A11 = 10z11 + 1A6 + 6A10 =

We accept: 1А11 = 94.3 -0.87 (correction + 0.03)

10z11=

After calculating the nominal sizes, we enter them in column 19 of the base selection card and, with a tolerance for processing, write them down in the “note” column of the Processing Scheme (Figure 1.5).

After we fill in column 20 and the column "approx.", We apply the obtained values of operational dimensions with a tolerance to the sketches of the route technological process. This completes the calculation of the nominal values of the long operating dimensions.

Map of base selection and calculation of operational sizes

master links

operation number

the name of the operation

Equipment model

processing

Operating

Bases

Dimensional chain equations

Closing links of dimensional chains

Operating dimensions

Surfaces to be machined

Thermal Depth layer

Selected from the conditions of measurement convenience

Technological options. bases

Accepted technical nol. and measure. bases

Designation

Limit dimensions

Tolerance mark and approx.

operating

Value

Rated

meaning

min

max

magnitude

Prepare.

GCM

13z14=1A14–1A–6A13

10z11=1A11–1A6-6A10

1z2=6А10–10А2+1А6

Turning

1P365

12z13=6A13–6A10+10A7–7A12

Figure 1.9 Map of base selection and calculation of operating sizes

Calculation of operating dimensions with double-sided allowance

When processing surfaces with a two-sided arrangement of the allowance, it is advisable to calculate the operating dimensions using a statistical method for determining the value of the operating allowance, depending on the selected processing method and on the dimensions of the surfaces.

To determine the value of the operating allowance by a static method, depending on the processing method, we will use source tables.

To calculate the operating dimensions with a two-sided allowance, for such surfaces we compose the following scheme calculation:

Figure 1.10 Layout of operating allowances

Drawing up a statement of calculation of diametrical operating dimensions.

Column 1: Indicates the numbers of operations according to the developed technology, in which the processing of this surface is performed.

Column 2: The processing method is indicated in accordance with the operating card.

Column 3 and 4: The designation and value of the nominal diametrical operating allowance, taken from the tables in accordance with the processing method and dimensions of the workpiece, are indicated.

Column 5: The designation of the operating size is indicated.

Column 6: According to the accepted processing scheme, equations are compiled for calculating the operating dimensions.

Filling out the statement begins with the final operation.

Column 7: The accepted operating size with a tolerance is indicated. The calculated value of the desired operating size is determined by solving the equation from column 6.

Sheet for calculating operating dimensions when machining the outer diameter of the axis Ø20k6 (Ø20)

	Name operations	Operating allowance		Operating size
	Name operations	Designation	Value	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 operating dimensions when machining the outer diameter of the 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 operating dimensions when machining the outer diameter of the axis Ø30k6 (Ø30)

Sheet for calculating operating 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 operating dimensions when machining a hole Ø8Н7 (Ø8 +0.015)

Sheet for calculating operating dimensions when machining a hole Ø12 +0.07

Sheet for calculating operating dimensions when machining a hole Ø14 +0.07

Sheet for calculating operating dimensions when machining a hole Ø9 +0.058

After calculating the diametrical operational dimensions, we will apply their values to 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 processing, the type and dimensions 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, set the depth of cut, minute feed, cutting speed. Let us give an example of calculating cutting conditions for two operations. For other operations, we assign cutting conditions according to, v.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 ST 25 carbide insert (Al 2 O 3 +TiCN+T15K6+TiN). The use of a carbide insert that does not need regrinding reduces the time spent on changing tools, in addition, the basis of this material is the improved T15K6, which significantly increases the wear resistance and temperature resistance of ST 25.

The geometry of the cutting part.

All parameters of the cutting part are selected from the source Cutter: α= 8°, γ = 10°, β = +3º, f = 45°, f 1 = 5°.

2. Brand coolant: 5% emulsion.

3. The depth of cut corresponds to the size of the allowance, since the allowance is removed in one trip.

4. Calculated feed is determined based on the requirements of roughness (, p. 266) and is specified according to the machine's passport.

S = 0.5 rpm.

5. Persistence, p.268.

6. Design cutting speed is determined from the specified tool life, feed and depth of cut from ,p.265.

where C v , x, m, y are coefficients [ 5 ], p.269;

T - tool life, min;

S - feed, rpm;

t – cutting depth, mm;

K v is a coefficient that takes into account the influence of the material of the workpiece.

K v = K m v ∙ K p v ∙ K and v ,

K m v - coefficient taking into account the influence of the properties of the material being processed on the cutting speed;

K p v = 0.8 - coefficient taking into account the influence of the state of the surface of the workpiece on the cutting speed;

K and v = 1 - coefficient taking 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 in terms of machinability.

K m v = 1∙

K v = 1.25 ∙ 0.8 ∙ 1 = 1,

7. Estimated speed.

where D is the workpiece diameter, mm;

V R - design cutting speed, m / min.

According to the passport of the machine, we accept n = 1500 rpm.

8. Actual speed cutting.

where D is the workpiece diameter, mm;

n is rotation frequency, rpm.

9. The tangential component of the cutting force Pz, H is determined by the source formula, p.271.

Р Z = 10∙С r ∙t x ∙S y ∙V n ∙К r,

where P Z is the cutting force, N;

C p, x, y, n - coefficients, p.273;

S - feed, mm / rev;

t – cutting depth, mm;

V – cutting speed, rpm;

К р – correction coefficient (К р = К mr ∙К j р ∙К g р ∙К l р, - numerical values of these coefficients from, pp. 264, 275).

K p \u003d 0.846 1 1.1 0.87 \u003d 0.8096.

P Z \u003d 10 ∙ 300 ∙ 2.8 ∙ 0.5 0.75 ∙ 113 -0.15 ∙ 0.8096 \u003d 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 hole Ø8 mm.

Machine model 2550F2, workpiece material - steel 45, tool material R6M5. Processing is carried out in one pass.

1. Substantiation of the brand of material and geometry of the cutting part.

Material of the cutting part of the tool R6M5.

Hardness 63…65 HRCe,

Bending strength s p \u003d 3.0 GPa,

Tensile strength s in \u003d 2.0 GPa,

Ultimate compressive strength s com = 3.8 GPa,

The geometry of the cutting part: w = 10° - the angle of inclination of the helical tooth;

f = 58° - the main angle in the plan,

a = 8° - rear angle to be sharpened.

2. Depth of cut

t = 0.5∙D = 0.5∙8 = 4 mm.

3. Estimated feed is determined based on the requirements of roughness .s 266 and is specified according to the machine's passport.

S = 0.15 rpm.

4. Persistence p. 270.

5. Design cutting speed is determined from the given tool life, feed and depth of cut.

where C v , x, m, y are the coefficients, p.278.

T - tool life, min.

S - feed, rpm.

t is the depth of cut, mm.

K V is a coefficient that takes into account the influence of the workpiece material, surface condition, tool material, etc.

6. Estimated speed.

where D is the workpiece diameter, mm.

V p - design cutting speed, m / min.

According to the passport of the machine, we accept n = 1000 rpm.

7. Actual cutting speed.

where D is the workpiece diameter, mm.

n - speed, rpm.

8. Torque

M cr \u003d 10 ∙ C 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 R o, N on , s. 277;

R o \u003d 10 ∙ C R D q S y K R,

where C P, q, y, K p, are the coefficients p.281.

P o \u003d 10 ∙ 68 8 1 0.15 0.7 0.92 \u003d 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. Sanding

Machine model 3T160, workpiece material - steel 45, tool material - normal electrocorundum 14A.

Plunge grinding by the periphery of the circle.

1. Brand of material, geometry of the cutting part.

Choose 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 p, mm / rev is determined by the formula from the source, s. 301, tab. 55.

S P \u003d 0.005 mm / rev.

4. The speed of the circle V K, m / s is determined by the formula from the source, p. 79:

where D K is the diameter of the circle, mm;

D K = 300 mm;

n K \u003d 1250 rpm - the rotational speed of the grinding spindle.

5. The estimated rotational speed of the workpiece n z.r, rpm is determined by the formula from the source, p.79.

where V Z.R is the selected workpiece speed, m/min;

V З.Р we will define according to tab. 55, p. 301. Let's take V Z.R = 40 m/min;

d З – workpiece diameter, mm;

6. Effective power N, kW will be determined according to the recommendation in

source page 300:

for plunge grinding with the periphery of the wheel

where the coefficient C N and the exponents r, y, q, z are given in, table. 56, p. 302;

V Z.R – billet speed, m/min;

S P - radial feed, mm / rev;

d З – 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 operations

Settlement and technological norms of time are determined by calculation.

There are the norm of piece time T pcs and the norm of time calculation. The calculation norm is determined by the formula on page 46, :

where T pcs - the norm of piece time, min;

T p.z. - preparatory-final time, min;

n is the number of parts in the batch, pcs.

T pcs \u003d t main + t auxiliary + t service + t lane,

where t main is the main technological time, min;

t aux - auxiliary time, min;

t service - time of service of the workplace, min;

t lane - time of breaks and rest, min.

The main technological time for turning, drilling operations is determined by the formula on page 47, :

where L is the estimated processing length, mm;

Number of passes;

S min - minute feed of the tool;

a - the number of simultaneously processed parts.

The estimated processing length is determined by the formula:

L \u003d L res + l 1 + l 2 + l 3.

where L cut - cutting length, mm;

l 1 - tool supply length, mm;

l 2 - tool insertion length, mm;

l 3 - tool overrun length, mm.

The service time of the workplace is determined by the formula:

t service = t maintenance + t org.service,

where t maintenance - maintenance time, min;

t org.service - organizational service time, min.

where is the coefficient determined by the standards. We accept.

Time for a break and rest is determined by the formula:

where is the coefficient determined by the standards. We accept.

We present the calculation of the norms of time 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 of tables 3.31 and 3.32 on page 85 .

L = 12 + 6 +2 = 20 mm.

Minute feed

S min \u003d S about ∙n, mm / min,

where S about - reverse feed, mm / about;

n is the number of revolutions, rpm.

S min = 0.5∙1500 = 750 mm/min.

min.

Auxiliary time consists of three components: for installation and removal of the part, for the transition, for measurement. This time is determined by cards 51, 60, 64 on pages 132, 150, 160 according to:

t set / removed = 1.2 min;

t transition = 0.03 min;

t meas = 0.12 min;

tsp \u003d 1.2 + 0.03 + 0.12 \u003d 1.35 min.

Maintenance time

min.

Organizational service time

min.

Break times

min.

The norm of piece time for the operation:

T pcs \u003d 0.03 + 1.35 + 0.09 + 0.07 \u003d 1.48 min.

035 Drilling

Drilling 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 done on a CNC machine. The cycle time of automatic operation of the machine according to the program is determined by the formula:

T c.a \u003d T o + T mv, min,

where T o - the main time of automatic operation of the machine, T o \u003d t main;

Tmv - machine-auxiliary time.

T mv \u003d T mv.i + T mv.x, min,

where T mv.i - machine-auxiliary time for automatic tool change, min;

T mv.h - machine auxiliary time for the execution of automatic auxiliary moves, min.

T mv.i is determined according to Appendix 47,.

We accept T mv.x \u003d T about / 20 \u003d 0.0115 min.

T c.a \u003d 0.23 + 0.05 + 0.0115 \u003d 0.2915 min.

The norm of piece time is determined by the formula:

where T in - auxiliary time, min. Determined by map 7, ;

a teh, a org, a ex – time for service and rest, determined by , map 16: a te + a org + a ex = 8%;

T in = 0.49 min.

040. Sanding

Definition of the main (technological) time:

where l is the length of the processed part;

l 1 - the value of the infeed and overrun of the tool on the map 43, ;

i is the number of passes;

S - tool feed, mm.

min

For the definition of auxiliary time, see card 44,

T in \u003d 0.14 + 0.1 + 0.06 + 0.03 \u003d 0.33 min

Determination of time for maintenance of the workplace, rest and natural needs:

where а obs and а otd - time for maintenance of the workplace, rest and natural needs as a percentage of the operational time on the map 50, :

a obs = 2% and a det = 4%.

Definition of the norm of piece time:

T w \u003d T o + T in + T obs + T otd \u003d 3.52 + 0.33 + 0.231 \u003d 4.081 min

1.11 Economic comparison of 2 options for operations

When developing a technological process of mechanical processing, the task arises to choose from several processing options one that provides the most economical solution. Modern methods of machining and a wide variety of machine tools allow you to create various technology options that ensure the manufacture of products that fully meet all the requirements of the drawing.

In accordance with the provisions for evaluating the economic efficiency of new technology, the most profitable option is recognized for which the sum of current and reduced capital costs per unit of output will be minimal. The sum of the reduced 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 hours of operation 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 the machine 1K62.

The value characterizes the efficiency of the equipment. A lower value for comparing machines with equal productivity indicates that the machine is more economical.

Hourly present cost

where - the main and additional wages, as well as accruals on social insurance to the operator and adjuster for the physical hour of operation of the serviced machines, kop/h;

The multi-station coefficient, taken according to the actual state in the area under consideration, is taken as M = 1;

Hourly costs for the operation of the workplace, kop/h;

Normative coefficient of economic efficiency of capital investments: for mechanical engineering = 2;

Specific hourly capital investments in the machine, kop/h;

Specific hourly capital investments in the building, kop / h.

The basic and additional wages, as well as social security contributions to the operator and the adjuster can be determined by the formula:

, kop / h,

where is the hourly tariff rate of a machine operator of the corresponding category, kop/h;

1.53 is the total coefficient representing the product of the following partial coefficients:

1.3 - coefficient of compliance with the norms;

1.09 - coefficient of additional salary;

1.077 - the coefficient of contributions to social security;

k - coefficient taking into account the salary of the adjuster, we take k \u003d 1.15.

The amount of hourly costs for the operation of the workplace in case of reduction

The machine load must be corrected with a factor if the machine cannot be reloaded. In this case, the adjusted hourly cost is:

, kop / h,

where - hourly costs for the operation of the workplace, kop/h;

Correction factor:

The share of semi-fixed costs in hourly costs at the workplace, we accept;

Machine load factor.

where Т ШТ – unit time for the operation, Т ШТ = 2.54 min;

t B is the release cycle, we accept t B = 17.7 min;

m P - the accepted number of machines for operations, m P = 1.

;

where - practical adjusted hourly costs at the base workplace, kop;

Machine coefficient showing how many times the costs associated with the operation of this machine are greater than those of the base machine. We accept.

kop/h

The capital investment in 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 the passes:

where - the production area occupied by the machine, m 2;

The coefficient taking into account the additional production area, .

kop/h

The cost of machining for the operation in question:

, cop.

cop.

2. Operation 10 is performed on the machine 1P365.

C \u003d 3800 rubles.

T PCS = 1.48 min.

kop/h

cop.

Comparing the options for performing a turning operation on various machines, we come to the conclusion that the turning of the outer surfaces of the part should be carried out on a 1P365 turret lathe. 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 the design of machine tools

In this course project, a machine fixture has been developed for operation No. 35, in which drilling, countersinking and reaming holes are performed using a CNC machine.

The type of production, the release 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 by a pneumatic cylinder).

The fixture is used to install only one part.

Consider the scheme of basing the part in the fixture:

Figure 2.1 Scheme of installing the 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 axes OY and OZ; 6 - support base - deprives of 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. Pneumatic actuator provides constant workpiece clamping force, as well as fast clamping and detachment of the workpiece.

2.3 Description of construction and principle of operation

Universal self-centering vice with two movable replaceable jaws is designed to secure axle-type parts during drilling, countersinking and reaming holes. Consider the design and principle of operation of the device.

On the left end of the body 1 of the vise, an adapter sleeve 2 is fixed, and on it is a pneumatic chamber 3. Between the two covers of the pneumatic chamber, a diaphragm 4 is clamped, which is rigidly fixed on a steel disk 5, in turn, fixed on the 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 rail 9. The rail 9 is engaged with the gear wheel 10, and the gear wheel 10 is engaged with the upper movable rail 11, on which the right movable sponge is installed and secured with two pins 23 and two bolts 17 12. The lower end of the pin 14 enters the annular 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 machined, are fixed with screws 19 on the movable jaws 12 and 13. The pneumatic chamber 3 is attached to the adapter sleeve 2 using 4 bolts 18. In turn, the adapter sleeve 2 is attached to the fixture body 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, the rod 7 and the rolling pin 8 to the right. to the left. Thus, the 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, the rod 7 and the rolling pin 8 are moved to the left; rolling pin 8 spreads sponges 12 and 13 with prisms 15.

2.4 Calculation of the machine fixture

Force calculation fixture

Figure 2.2 Scheme for determining the clamping force of the workpiece

To determine the clamping force, we simply depict the workpiece in the fixture and depict the moments from the cutting forces and the desired required clamping force.

In figure 2.2:

M - torque on the drill;

W is the required fixing force;

α is the angle of the prism.

The required clamping force of the workpiece is determined by the formula:

, H,

where M is the torque on the drill;

α is the angle of the prism, α = 90;

The coefficient of friction on the working surfaces of the prism, we accept ;

D is the workpiece diameter, D = 75 mm;

K is the 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 taking into account the presence of random irregularities on the workpieces, which entails an increase in cutting forces, we accept k 1 = 1;

k 2 - coefficient taking into account the increase in cutting forces from progressive blunting of the cutting tool, k 2 = 1.2;

k 3 - coefficient taking into account the increase in cutting forces during interrupted cutting, k 3 \u003d 1.1;

k 4 - coefficient taking into account the variability of the clamping force when using pneumatic lever systems, k 4 \u003d 1;

k 5 - coefficient taking into account the ergonomics of manual clamping elements, we take k 5 = 1;

k 6 - coefficient taking 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

M \u003d 10 ∙ C M ∙ D q ∙ S y ∙ K r.

where C M, q, y, K p, are the coefficients, p.281.

S - feed, mm / rev.

D – drilling diameter, mm.

М = 10∙0.0345∙ 8 2 ∙ 0.15 0.8 ∙0.92 = 4.45 N∙m.

Let us determine the force Q on the rod of the diaphragm pneumatic chamber. The force on the rod changes as it moves, since the diaphragm begins to resist in a certain area of \u200b\u200bdisplacement. The rational length of the rod stroke, at which there is no sharp change in the force Q, depends on the calculated diameter D, thickness t, material and design of the diaphragm, and also on the diameter d of the supporting 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:

, H,

Where p is the pressure in the pneumatic chamber, we take p = 0.4∙10 6 Pa.

The force on the rod when moving 0.3D:

, N.

Calculation of fixture for accuracy

Based on the accuracy of the maintained size of the workpiece, the following requirements are imposed on the corresponding dimensions of the fixture.

When calculating the accuracy of fixtures, the total error in the processing of the part should not exceed the tolerance value T of the size, i.e.

The total fixture error is calculated using the following formula:

where T is the tolerance of the size being performed;

Based error, since in this case there is no deviation of the actually achieved position of the part from the required one;

Pinning error, ;

Fixture installation error on the machine, ;

Part position error due to wear of fixture elements;

Approximate wear of the installation elements can be determined by the formula:

where U 0 is the average wear of the mounting elements, U 0 = 115 µm;

k 1 , k 2 , k 3 , k 4 are coefficients, respectively, taking into account the influence of the workpiece material, equipment, processing conditions and the number of workpiece settings.

k 1 = 0.97; k 2 = 1.25; k 3 = 0.94; k4 = 1;

We accept microns;

Error from skew or displacement of the tool, since there are no guide elements in the fixture;

The coefficient taking into account the deviation of the dispersion of the values of the constituent quantities from the law of normal distribution,

Coefficient that takes into account the reduction in the limiting value of the basing error when working on tuned machines,

A coefficient that takes into account the share of the processing error in the total error caused by factors independent of the fixture,

Economic accuracy of processing, = 90 microns.

3. Design of special control equipment

3.1 Initial data for the design of the test fixture

Control and measuring devices are used to check the compliance of the parameters of the manufactured part with the requirements of technological documentation. Preference is given to devices that allow you 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 device, is convenient in operation and does not require high qualification of the controller.

Parts of the axle type in most cases transmit significant torques to the mechanisms. In order for them to work flawlessly for a long time, the high accuracy of the execution of the main working surfaces of the axis in terms of diametrical dimensions is of great importance.

The inspection process mainly involves a complete check of the radial runout of the outer surfaces of the axle, which can be carried out on a multidimensional inspection fixture.

3.2 Schematic diagram of the machine tool

Figure 3.1 Schematic diagram of the test fixture

Figure 3.1 shows a schematic diagram of a device for controlling the radial runout of the outer surfaces of the axle part. The diagram shows the main parts of the device:

1 - fixture body;

2 - headstock;

3 - tailstock;

4 - rack;

5 - indicator heads;

6 - controlled detail.

3.3 Description of construction and principle of operation

The headstock 2 with a mandrel 20 and the tailstock 3 with a fixed reverse center 23 are fixed on the body 1 with the help of screws 13 and washers 26, on which the axle to be checked is mounted. The axial position of the axis is fixed by a fixed reverse 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 possibility of rotation relative to the longitudinal axis thanks to the bushings 4. at the left end quill 5, a handwheel 19 with a handle 22 is installed, which is fixed with a washer 8 and a pin 28, the torque from the handwheel 19 is transmitted to the quill 5 using the key 27. The rotational movement during measurement is transmitted to the adapter 6 through the 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 accurate backlash-free locating 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 brackets 12 move and are fixed with screws 14. On brackets 12, rolling pins 10 are installed with screws 14, on which screws 15, nuts 17 and washers 24 fixed IG 30.

Two IG 30 serve to check the radial runout of the outer surfaces of the axis, which give one or two turns and count the maximum readings of the IG 30, which determine the runout. The device provides high performance of the control process.

3.4 Calculation of the test fixture

The most important condition that control devices must satisfy is to ensure the necessary measurement accuracy. Accuracy largely depends on the method of measurement adopted, on the degree of perfection of the concept and design of the device, as well as on the accuracy of its manufacture. An equally important factor affecting the accuracy is the accuracy of the surface used as a measuring base for the controlled parts.

where is the error in the manufacture of the installation elements and their location on the body of the device, we take mm;

The error caused by the inaccuracy in the manufacture of transmission elements is taken mm;

The systematic error, taking into account the deviations of the mounting dimensions from the nominal ones, is taken mm;

Basing error, accept ;

The error of the displacement of the measuring base of the part from the given position, we accept mm;

Fixing error, accept mm;

The error from the gaps between the axes of the levers, we accept;

The error of deviation of the installation elements from the correct geometric shape, we accept;

Measurement method error, accept mm.

The total error can be up to 30% of the controlled parameter tolerance: 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 for obtaining a given accuracy.

As the tuning dimensions, we accept the dimensions corresponding to the middle of the tolerance field of the operational size. The tolerance value for the setting size is accepted

T n \u003d 0.2 * T op.

where T n is the tolerance for the setting size.

T op - tolerance for the operating size.

For example, in this operation we sharpen the surface Ø 32.5 -0.08, then the setting size will be equal to

32.5 - 32.42 = 32.46 mm.

T n \u003d 0.2 * (-0.08) \u003d - 0.016 mm.

Setting size Ø 32.46 -0.016 .

The calculation of other dimensions is carried out similarly.

Project Conclusions

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 conditions, time standards, equipment and tooling are indicated. For the drilling operation, a special machine tool has been designed to ensure the required accuracy of the workpiece, as well as the required clamping force.

When designing the technological process of manufacturing the 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 for obtaining a given accuracy.

During the implementation of the project, a settlement and explanatory note was drawn up, which describes in detail all the necessary calculations. Also, the settlement and explanatory note contains applications, which include operational maps, as well as drawings.

Bibliography

1. Handbook of technologist-machine builder. In 2 volumes / ed. A.G. Kosilova and R.K. Meshcheryakova.-4th ed., revised. and additional - M .: Mashinostroenie, 1986 - 496 p.

2. Granovsky G.I., Granovsky V.G. Metal cutting: Textbook for mechanical engineering. and instrumentation specialist. universities. _ M.: Higher. school, 1985 - 304 p.

3. Marasinov M.A. Guidelines for calculating operating sizes. - Rybinsk. RGATA, 1971.

4. Marasinov M.A. Design of technological processes in mechanical engineering: Textbook. - Yaroslavl. 1975.-196 p.

5. Mechanical Engineering Technology: Textbook for the implementation of the 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, for servicing the workplace and preparatory - final for the technical regulation of machine work. Mass production. M, Mechanical engineering. 1964.

7. Anserov M.A. Devices for metal-cutting machine tools. 4th edition, corrected. and additional L., Mechanical engineering, 1975

Before you figure out how the shaft and axle differ from each other, you should have a clear idea of what these parts actually are, what and where they are used for and what functions they perform. So, as you know, shafts and axles are designed to hold rotating parts on them.

Definition

Shaft- this is a part of the mechanism that has the shape of a rod and serves to transfer torque to other parts of this mechanism, thereby creating a general rotational movement of all parts located on it (on the shaft): pulleys, eccentrics, wheels, etc.

Axis- this is a part of the mechanism, designed to connect and fasten the parts of this mechanism together. The axis takes only transverse loads (bending stress). Axes are fixed and rotating.

Axis

Comparison

The main difference between an axle and a shaft is that the axle does not transfer torque to other parts. It is only affected by transverse loads and does not experience torsion forces.

The shaft, unlike the axis, transmits a useful torque to the parts that are fixed to it. In addition, the axes are both rotating and fixed. The shaft is always rotating. Most shafts can be divided according to the geometric shape of the axis into straight, crank (eccentric) and flexible. There are also crankshafts or indirect ones, which serve to convert reciprocating movements into rotational ones. The axes, in their geometric form, are only straight lines.

Findings site

The axle carries the rotating parts of the mechanism without transmitting any torque to them. The shaft transmits a useful torque, the so-called rotating force, to other parts of the mechanism.
The axis can be either rotating or stationary. The shaft is only rotating.
The axis has only a straight line. The shape of the shaft can be straight, indirect (crankshaft), eccentric and flexible.

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1. Descriptiondesign and purpose of the part

Axes serve to support various parts of machines and mechanisms rotating with them or on them. The rotation of the axis, together with the parts installed on it, is carried out relative to its supports, called bearings. An example of a non-rotating axle is the axle of a hoisting machine block, and a rotating axle is a wagon axle. The axles perceive the load from the parts located on them and work in bending.

The design of the axle, its dimensions and rigidity, technical requirements, production program are the main factors that determine 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 of a circular cross section of various diameters and lengths. The axis length is 370 mm, the maximum diameter is 50 mm, the minimum is 48, the maximum hole diameter is 14H12 (+0.18), and the minimum is 10 mm.

According to fig. it can be seen that the axis part has the following surfaces:

Surface 1 and 2 fig. 1: a square with a side of 40d11 mm and top deviations -0.08, bottom -0.24, roughness Ra = 6.3 µm.

Surface 3 and 5 fig. 1: diameter 50d11 mm and top deviations -0.08, bottom -0.24; roughness Ra = 6.3 µm

Surface 4 fig. 1: diameter 48mm; roughness Ra = 6.3 µm.

Surface 6 fig. 1: hole diameter 14H12; upper deviation +0.18, K3/8 thread; roughness Ra = 3.2 µm

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, as it contains simple surface profiles, its processing does not require specially designed fixtures and machines. Axis surfaces are processed on turning, drilling, milling and grinding machines. The required dimensional accuracy and surface roughness are achieved by a relatively small set of simple operations, as well as a set of standard cutters, milling cutters and grinding wheels.

2. Workpiece material

The chemical composition of steel 40X GOST4543 is presented in table 1.

Table 1

The workpiece of the “axis” part is made of structural alloyed steel of the Stal40Kh GOST4543 grade.

Table 1 shows that in the chemical composition of steel 40X GOST4543, the maximum percentage of Chromium (Cr) is 0.80 - 1.10, and the minimum percentage of Phosphorus (P) is 0.035 and Sulfur (S) is 0.035.

The mechanical properties of steel 40X GOST4543 are presented in Table 2.

table 2

The physical properties of steel 40X GOST4543 are presented in Appendix 1.

Technological route for processing the part "axis"

	Name equipment	Cutting conditions	Time\min

Procurement Select a workpiece circle w 60 mm Steel 40X GOST4543 Cut the workpiece to a size of 380 mm	Band saw machine
Turning cut end Sharpen (rough) outer w 52 mm and outer w 49 mm to a distance of 140 mm drill holes w 14H to a depth of 205 mm cut thread K 3/8?	Lathe 16K20 cutting cutter t5k10 Cutter T15K6 Drill w 14 mm Tap K 3/8"" for R6M5 conical thread
Drill holes sh 10	drilling vertical machine 2H135 drill w 10 mm
Milling Mill a square from 2 sides to a size of 60 mm with a side of 40d11 ((-0.08) / (-0.24))
Thermo. treatment
Turning (finishing) Sharpen up to w 50d11 in size 55 mm and up to w 48 mm in size 140 mm	Lathe 16K20
Locksmith Blunt sharp edges	file
Control	Check for compliance with the specified parameters

Operation 005 cut the workpiece to a size of 380 mm. Band saw equipment is equipment for cutting metal profiles of different sections and diameters by sawing into workpieces of different lengths. The list of materials to be sawn using band saws is steel and its alloys. Method of basing clamp in tesky.

Operation 010 Turning cut the end, sharpen (rough) outer w 52 mm and outer w 48 mm to a distance of 140 mm drill hole w 14H12 (+0.18) to a depth of 205 mm cut a thread K 3/8?. Equipment: the 16K20 lathe is a universal screw-cutting lathe, which can be used to turn materials in the form of bodies of revolution, cutting modular, metric, and also to carry out a wide range of turning procedures (drilling using different types of drills, countersinking, and so on) with hot-rolled and cold-rolled products. Basing when turning in centers, when drilling holes sh 14H12 (+0.18) and threading K 3/8? clamp into a three-jaw chuck.

Cutting cutter T5K10, 32x20x170 mm, GOST 18884-73

Plate hard alloy Т5К10

Through-hole cutter T15K6 20x30x170 2102-0059

Line turning cutter (right and left) with a T15K6 carbide insert, GOST 18878, used for turning external surfaces and chamfers.

K3/8 machine-manual tap for taper inch thread GOST 6227 scope - cutting of internal taper inch thread with a profile angle of 60° by machine or by hand.

Operation 015 drilling, drilling holes. sh 10. Equipment vertical drilling machine 2H135, with the help of which the operations of drilling, reaming and reaming holes, as well as trimming and reaming can be equally successfully performed. 2H135 machines are also easy to use due to the fact that with the help of the feed box and spindle speeds, you can select the optimal modes for obtaining and processing holes with different parameters and in materials with different characteristics.

A drill is a cutting tool, with a rotary cutting motion and an axial feed motion, designed to make holes in a continuous layer of material.

Operation 020 Milling, mill a square from 2 sides to a size of 60 mm with a side of 40d11 ((-0.08)/(-0.24)). Equipment horizontal milling machine X6132 is a multifunctional machine designed for various processing of metal parts. It is able to process flat, stepped surfaces, cut grooves and cut gears with cylindrical, angle, end, shaped, spherical cutters. The reinforced design of the machine allows you to load heavy workpieces weighing up to 500 kg. Good performance is due to high power and a wide range of processing speeds. The use of modern cutting tools allows you to achieve better results.

End mill, material - high-speed steel P18, number of teeth - 18. The productivity of the end mill is low, and the described method of milling square faces can be recommended for small-scale production.

Operation 025 heat treatment Rockwell hardness 34…42 HRC

Operation 030 turning (finishing) to sharpen up to w 50d11 in size 55 mm

Equipment lathe 16K20. Bases in the centers.

Operation 035 locksmith to blunt the edges. File equipment.

Operation 040 control check for compliance with the specified parameters.

The ShTsT-1 equipment is universal, the jaws of which are located in one direction and are made of carbide materials; a threaded plug gauge is used to check the internal thread.

3. Determining the type of production

The nature of the technological process largely depends on the type of production of parts (single, serial, mass). This is due to the fact that in various types of industries it is economically expedient to use equipment, devices, different in complexity and versatility of cutting and measuring tools that differ in degree of versatility, mechanization and automation. Depending on the type of production, the organizational structures of the workshop also change significantly: the arrangement of equipment, systems for servicing workplaces, and the range of parts. According to Table 4, we preliminarily set the type of production depending on the weight and number of parts to be manufactured during the year.

Table 4. Type of production

Part weight, kg.	Type of production
	single	Small-scale	Medium series	large-scale	Mass

Serial production is conditionally divided into small-scale, medium-scale and large-scale production, depending on the number of parts in the series. Thus, with an annual output of 350 pieces/year, our production is small-scale.

Workpiece basing

010 Turning operation (roughing)

Equipment

Screw-cutting lathe model 16K20: Table 5

Table 5

fixture

Rotating centers according to GOST 8742-92.

Cutting tool

Cut-off turning cutter T5K10, 32x20x170 mm, GOST 18884-73 T5K10 hard alloy plate, straight through cutter T15K6 20x30x170 2102-0059, straight through straight turning cutter (right and left) with T15K6 hard alloy plate, GOST 18878.

Measuring tool

Caliper ShTs-I according to GOST 166-80, measurement limit 0-125 mm, division value 1 mm, measurement accuracy 0.1 mm.

4. Cutting conditions

a) First pass. Sharpen the part on top rough to Ш52 at length l=370 mm; Ra=12.5 µm.

1) Depth of cut for end face t = 5 mm.

2) Feed according to the reference book sp \u003d 0.45 mm / rev.

3) Cutting speed v, m/min.

where Сv=350 - Considers the material being processed and the material of the cutting part of the cutter;

m = 0.2 xV=0.15 yV = 0.35 - exponents;

T = 60 - tool life, min;

Kv - speed coefficient

where KPV \u003d 0.96 - the state of delivery of the workpiece;

КIV =0.65 - material of the cutting part;

KMV = 0.90 - processed material;

K=0.70 - coefficient of the cutter parameter;

Kg=0.97 - coefficient of the cutter parameter.

0.96 0.65 0.90 0.70 0.97=0.38

All values of the coefficients are selected according to the recommendation of the handbook.

4) The number of revolutions of the spindle.

5) Spindle speed according to the passport n=1000 rpm.

7) Cutting force.

Рz=Срz tхр syp vpr kr,

where kр - coefficient of power

where k1=1.04 - processed material.

k2=0.89 - main angle in plan

kp=1.04 0.89=0.93

Ср=3200 - processed material and material of the cutting part

Рz=3000 4.51.0 0.650.75 56.54-0.15 0.93=5424 N

8) Effective cutting power.

where h \u003d 0.75 - efficiency machine.

NEF = 6.75 kW 15 kW = NCT.

9) Basic transition time:

where y1=0 is the value of the tool infeed:

l - the main processing length, l=180 mm;

b) The second transition.

Sharpen the part on top up to Ш49 mm at length l=140 mm, Ra=12.5 µm

The cutting mode is taken according to the first transition.

Main time.

Piece calculation time:

where Tpz=120 - preparatory and final time for the operation;

operational time.

top=Uto+Utv,

Уto=to1+to2=0.82+0.31=1.13 min

where Уtп=20 - auxiliary time for the operation, min;

top=1.13+20=21.13 min

Tshtk= +=28.6 min

c) The third transition.

Drill holes w 14H12 (+0.18) mm to a length l=205 mm, Ra=12 µm

Drilling operation

Equipment

Drilling vertical machine 2H135 specifications listed in Appendix 2.

Cutting tool

1. Drills with diameters: 10 mm according to GOST 2692-92. Drill material high speed steel. Durability of drills Т=45 min. Geometric parameters: 2f=116°; r=2°; w=30°; b=2-5°.

measuring tool

1. Caliper ШЦ-I GOST 166-80, measurement limits 0-125 mm, division value 1 mm, measurement accuracy 0.1 mm.

Cutting data calculation

a) First pass. Drill a hole with a diameter of 10 mm at a length of l = 24 mm, Ra = 12.5 µm.

1) Depth of cut t=0.5d=5 mm.

3) Feed according to the machine passport s=0.25 rpm.

4) Cutting speed V=20 m/min.

5) Spindle speed.

6) Spindle speed according to the passport n=630 rpm.

7) Actual cutting speed:

8) Torque.

Тcr=cm Ddm sqm cr, (2.12)

where cm is the material being processed and the material of the drill taken as a standard, cm = 0.345;

qm - exponent;

mind is an exponent;

kmr - processed material, kmr=1.06.

Tcr=0.345 10I 0.250.8 1.06=12.1 N m

9) Cutting power.

? , (2.5)

where h \u003d 0.75 - efficiency machine.

NE = 0.78 kW 3 kW = NCT.

10) Basic transition time:

where y1=3 is the value of the tool infeed:

l - the main processing length, l=24 mm;

y2 - tool overrun value, y2=0 mm;

Piece calculation time

where T pz \u003d 50 - preparatory and final time for the operation

020 Milling operation

Equipment

Horizontal milling machine X6132

Specifications

Table size (L x W), mm 1320x320

Gap x Width x Number of T-slots, mm x mm x pcs. 18x3

Max. workpiece weight, kg 500

Longitudinal movement, mm 700

Cross movement, mm 255

Vertical movement, mm 320

Longitudinal feed range, mm/min 23.5~1180/18

Cross feed range, mm/min 23.5~1180/1

fixtures

Hydraulic prisms, knives.

Cutting tool

HSS end mill

Number of cutting teeth - 4.

Dimensions: working part diameter - 10 mm

shank diameter - 10 mm

working length - 22 mm

total length - 72 mm.

measuring tool

Metal ruler GOST 427-80, measurement limits 0-40 mm, scale division 1 mm.

Cutting conditions

a) First pass. Mill the part on both sides. Maintain the size l=310 60 mm, Ra=6.3 microns.

1) Depth of cut for end face t = 2 mm.

2) Feed sp = 0.12 mm/rev.

3) Cutting speed v, m/min.

where Cv=330 - takes into account the material being processed and the material of the cutting part of the cutter;

m = 0.2 xV=0.1 yV = 0.2

qv=0,2 - exponents according to the directory

T = 120 - tool life, min;

Kf=0.87 - main angle in plan;

KN=0.90 - state of delivery of the workpiece;

KM = 0.77 - processed material;

Ku =0.65 - material of the cutting part of the cutter;

120.8 m/min

4) Spindle speed.

where D - cutter diameter, D=10 mm

5) Spindle speed according to the passport n=504 rpm.

6) Actual cutting speed:

v===126.6 m/min

7) Minute feed:

sm=sz n Z=0.12 10 504=604.8 mm/min (2.3)

8) Minute feed according to the passport Smin=560 mm/min

9) Actual feed per tooth:

sz===0.06 mm/tooth

10) Cutting force.

where kp=1.31 - processed material.

Cp=8250; Xp=1.0; Yp=0.75; u=1.1; qv=1.3; spr=0.2

11) Feed force.

Px=0.3 Pz=0.3 2235=670.5 N;

Px=670.5 N< 2400 Н = [Рх]

12) Effective cutting power.

where h \u003d 0.75 - efficiency machine.

NEF = 6.2 kW 15 kW = NCT.

13) Basic transition time:

where y1 is the value of the tool infeed:

l - the main processing length, l=80 mm;

y2 - tool overrun value, y2=5 mm;

015 Turning finishing

Equipment

Screw-cutting lathe model 16K20TS.

For technical data, see operation 010.

Cutting tool

Straight line turning cutter, finishing in accordance with GOST 6743-93 type 5, according to the recommendation, the material of the cutting part is T15K6. Tool life T=60 min; ВЧН=16Ч25 - holder section; f1=8; b=8 - back angle; r \u003d 0 - front angle; l \u003d 0 - the angle of inclination of the blade; r = 2 mm - radius at the top of the cutter; f=0.2 mm.

Measuring tool

Metal ruler according to GOST 427-80, measurement limits 0-125 mm, division value 1 mm.

Caliper ШЦ-I according to GOST 166-80, measurement limit 0-125 mm, division value 1 mm, measurement accuracy 0.1 mm

Cutting conditions

Piece calculation time

where Тпз=60 - preparatory and final time for the operation

operational time.

top=Uto+Utv,

where Uto - the sum of the main time, min;

Уto=tо1+tо2+tо3+tо4+tо5=1.13+1.8+0.9+0.71+0.1=4.64 min

where Yt in =24 - auxiliary time for the operation, min;

5. Purpose and device of the machine tool

detail technical axis blank

Consider the machine tool designed within the framework of this course work (Figure 2). The machine fixture is designed for fastening workpieces installed along the outer and inner diameters.

Preliminary adjustment of the cams 15 to a given size is carried out by moving them along the corrugated surface 14. Due to the flat connection of the rod 11 with the clutch 13, the cams can self-adjust, resulting in uniform clamping of the workpiece. The drive is pneumatic.

Three-jaw chuck

Fixture calculation

The initial data for calculating the fixture is the cutting force and torque.

We perform the calculation for operation 010 - turning.

Cutting force = 1060.85 N.

The main component of the cutting force Pz forms the cutting moment.

And the moment of friction Mtr is determined by the formula:

We compose the equation of moments about the x-axis:

We compose the equation of forces about the x-axis:

Lathe setup

Adjustment it includes the setting of the operating chart of adjustment of the specified values of the spindle speed and feed rate when moving the moving parts of the machine (calipers, tables, etc.). For this purpose, the gearboxes and feeds are adjusted. Arrangement (or, if necessary, checking the correct location) of electric, hydraulic and pneumatic stops and converters for controlling the operation of units, installing clamping chucks and reconciling the correct location of the cutting tool (size settings) according to the operational drawing.

In the process of setting up and operating metal-cutting machines, their geometric accuracy (for example, spindle runout) is periodically checked for compliance with the standards specified in the equipment passport.

During the current setup of the machine (sub-adjustment), only a series of transitions indicated above are performed (starting from the fourth, except for the seventh and eighth). The equipment start-up time at the beginning of each shift should be no more than 0.5 hours.

Setting up the milling machine

Adjustment of the milling machine, carry out its preparation for work, which consists of checking the serviceability and readiness of the machine to perform various milling operations. At idle, they check the execution by the machine of commands to start and stop the electric motor, turn the spindle rotation on and off, turn the mechanical table feeds on and off.

After making sure that the machine is working, proceed to its adjustment. We will consider the methods of setting up machines of the milling group using the example of universal console milling machines with manual control.

Drilling machine setup

Before starting work on the drilling machine, it is necessary to make its adjustment.

Setting up the machine means preparatory work for the installation and alignment of the cutting tool and fixtures for fastening workpieces, inspection and trial run of the machine, as well as the selection and installation of the required spindle speed and tool feed rate specified in the technological map or assigned according to special tables. In mass and serial production, the adjustment of machines is usually carried out by highly qualified adjustment workers, in small-scale and individual production, by the drillers themselves.

However, regardless of who set up the machine, before starting work, the machine operator must inspect the machine and test it at idle. In this case, the condition of the spindle should be checked, which should rotate without runout and, like the machine table, move smoothly up and down.

If any malfunctions of the machine are found, they should be reported to the foreman or adjuster.

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Axis in the mechanism. Shafts and axles general information

Shafts and axles General information

Variety of shafts and axles

Structural elements of shafts and axles

1.1 Service purpose and technical characteristics of the part

1.2 Determining the type of production and batch size of the part

1.3 Selecting the way to obtain the workpiece

1.4 Purpose of methods and processing steps

1.7 Selection of equipment, tooling, cutting and measuring tools

1.8 Calculation of operating dimensions

1.9 Calculation of cutting conditions

1.10 Rationing operations

1.11 Economic comparison of 2 options for operations

2. Design of special machine tools

3.5 Development of a setup chart for operation No. 30

Project Conclusions

Definition

Comparison

Findings site

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