Coursework: Technological process of machining parts

20.09.2019

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Introduction

1. Initial data for the task

2. Type of production, number of parts per batch

3. Type of workpiece and processing allowances

4. Structure technological process

5. Selection of equipment and devices

6. Tool selection

7. Calculation of cutting conditions

8. Setting time standards, determining the price and cost of machining a part

9. Basic information about safety precautions when working on metal-cutting machines

10. Design of the device

11. Design technical documentation

Literature

Introduction

Modern mechanical engineering places very high demands on the accuracy and condition of the surfaces of machine parts, which can be achieved mainly only by mechanical processing.

Metal cutting is a set of actions aimed at changing the shape of a workpiece by removing allowance with cutting tools on metal-cutting machines, ensuring the specified accuracy and roughness of the processed surface.

Depending on the shape of the parts, the nature of the surfaces being processed and the requirements for them, they can be processed different ways: mechanical - turning, planing, milling, broaching, grinding, etc.; electrical - electric spark, electric pulse or anodic-mechanical, as well as ultrasonic, electrochemical, radiation and other processing methods.

The process of processing metals by cutting plays a leading role in mechanical engineering, since the accuracy of shapes and sizes and the high frequency of surfaces of metal parts of machines in most cases are ensured only by such processing.

This process is successfully used in all industries without exception.

Metal cutting is a very labor-intensive and expensive process. For example, on average in mechanical engineering the cost of processing workpieces by cutting is from 50 to 60 times the cost of finished products.

Metal cutting is usually carried out on metal-cutting machines. Only certain types of cutting processing related to metalwork are performed manually or using mechanized tools.

The following trends are noticeable in modern methods of metal machining:

processing workpieces with small allowances, which leads to savings in metals and an increase in the share of finishing operations;

wide application methods of hardening treatment without removing chips by rolling with rollers and shot blasting balls, mandreling, embossing, etc.;

the use of multi-tool processing instead of single-tool processing and multi-edge cutting tools instead of single-edge;

increasing cutting speeds and feeds;

an increase in the part of work performed on automatic and semi-automatic machines, robotic complexes using program control systems;

extensive modernization of metal-cutting equipment;

the use of high-speed and multi-place devices for securing workpieces and mechanisms when automating universal metal-cutting machines;

production of parts from special and heat-resistant alloys, the machinability of which is significantly worse than that of conventional metals;

participation of technologists in the development of machine designs to ensure their high manufacturability.

It is more rational to immediately receive a finished part, bypassing the procurement stage. This is achieved by using precise casting and injection techniques, powder metallurgy. These processes are more progressive, and they will be increasingly introduced into technology.

1. OriginaldataBytask

mechanical metal cutting processing part

Job title:

Technological process of machining a part.

The initial data for the task are shown in Table 1:

Table 1

Chemical composition of steel (GOST 1050-88) in table 2:

table 2

Mechanical properties of steel 30 GOST 1050-88 in table 3:

Table 3

Technological properties of steel 30 GOST 1050-88 in table 4:

Table 4

2 . Typeproduction,quantitydetailsVparties

The number of parts in a batch can be determined by the formula:

where N is the annual parts production program, pcs.

t is the number of days for which it is necessary to have a supply of annual parts.

F - number of working days in a year.

241(pcs.) From Table 1, select the type of production:

Table 1

Type of production - serial.

Batch production - products are manufactured or processed in batches (series) consisting of similar parts of the same size, launched into production simultaneously.

Now from Table 2 we select the type of production:

table 2

The production is medium-scale and produces small (light) parts, with quantities per batch ranging from 51 to 300 items.

3. ViewblanksAndallowancesonprocessing

A workpiece is a production item from which the required part is made by changing the shape, size, quality of surfaces and material properties. The choice of the type of workpiece depends on the material, shape and size, its purpose, working conditions and load experienced, and the type of production.

The following types of blanks can be used for the manufacture of parts:

a) casting from cast iron, steel, non-ferrous metals, alloys and plastics for shaped parts and housing in the form of frames, boxes, axle boxes, jaws, etc.;

b) forgings - for parts subject to bending, torsion, and tension. In serial and mass production, stampings are mainly used, in small-scale and individual production, as well as for large-sized parts - forgings;

c) hot-rolled and cold-rolled products - for parts such as shafts, rods, disks and other shapes that have slightly changed cross-sectional dimensions.

In our case, it is advisable to make the lid from rolled stock, since the circle fits well with the dimensions of the part.

Allowances for processing are indicated in table 1:

Table 1 - allowances and processing tolerances

In this case, it is best to choose a steel casting.

Foundry is a branch of mechanical engineering that produces shaped blanks or parts by pouring molten metal into a special mold that has the configuration of the blank. When cooled, the poured metal hardens and, in its solid state, retains the configuration of the cavity into which it was poured. The final product is called casting. During the crystallization of molten metal, mechanical and operational properties castings

Casting produces various designs of castings weighing from a few grams to 300 tons, lengths from several centimeters to 20 m, with walls 0.5-500 mm thick. For the production of castings, many casting methods are used: in sand molds, in shell molds, in lost wax, in a mold, under pressure, centrifugal casting, etc. The scope of application of a particular casting method is determined by the volume of production, the requirements for geometric accuracy and surface roughness of the castings , economic feasibility and other factors.

4. Structuretechnologicalprocess

Part manufacturing route

1. Drilling (machine 2N135):

a) Drill hole 35

b) countersink 38.85

c) (machine T15K6) - reamer 40

(Normalized 3 jaw chuck)

2. Locksmith

3. (machine brand 16K20F3) CNC lathe

a) cut the end to size 163 (-0.3)

b) sharpen the sphere R150

(Spreading mandrel (collet))

4. (machine brand 16K20F3) CNC lathe

a) trim the end maintaining size 161 (-0.3)

b) sharpen the sphere R292

(Spreading mandrel)

5. Horizontal milling machine brand 6M82G with an 8 mm end mill, 10.5 mm deep. (Special device)

6. Locksmith.

7. Cementation.

8.Hardening

9.Vacation

10.Cleaning and hardness control

11.Cleaning (heat treatment and calibration)

12. (machine brand 2N135) reamer 40.

13. (machine brand 3E710A) surface grinding. Reset the grinding to size 160.

14. Washing.

15. Test.

5. ChoiceequipmentAnddevices

When choosing the type of machine and the degree of automation, the following factors must be taken into account:

1. Overall dimensions and shape of the part;

2. The shape of the treated surfaces, their location;

3. Technical requirements for the accuracy of dimensions, shape and roughness of processed surfaces;

size 4 production program, characterizing the type of production of this part.

In single small-scale production, universal machines are used, in serial production along with universal machines Semiautomatic and automatic machines are widely used in large-scale and mass production - special machines, automatic machines, modular machines and automatic lines.

Automatic machines with numerical control are now increasingly used in mass production, allowing quick changeover from processing one part to another by replacing a program recorded, for example, on punched paper tape or magnetic tape.

We select machines according to the tables below:

Table 1. Screw-cutting lathes

Index	Machine models

Largest diameter of the workpiece, mm
Distance between centers, mm

Spindle speed, rpm
Number of caliper feed stages
Caliper supply. Mm. Longitudinal transverse	0,08-1,9 0,04-0,95	0,065-0.091 0,065-0,091	0,074,16 0,035-2,08	0,05- 4,16 0,035-2,08
Main electric motor power, kW
Machine efficiency
Maximum permissible feed force by the mechanism, n

Table 2. Horizontal and vertical milling machines

Index	Machine models
	Horizontal	Vertical

Working surface of the table, mm
Number of spindle speed steps
Spindle speed, rpm
Number of feed stages
Table feed, mm/min: Longitudinal Transverse			25-1250 15,6-785
Maximum permissible feed force, kN
Main motor power
Machine efficiency

Table 3. Vertical - drilling machines

Index	Machine models
	2N118	2N125	2N135
Largest nominal drilling diameter.mm	18	25	35
Vertical movement of the drilling head, mm	150	200	250
Number of spindle speed steps	9	12	12
Spindle rotation speed rpm	180-2800	45-2000	31,5-1400
Number of feed feet	6	9	9
Spindle feed.rpm	0,1-0,56	0,1-1,6	0,1-1,6
Torque on the spindle, N	88	250	400
Maximum permissible feed force, N	5,6	9	15
Electric motor power, kW	1,5	2.2	4
Machine efficiency	0,85	0,8	0,8

From the tables we select the following machines: 2N135 16K20F3 6M82G 3E10A

6 . Choicetool

1 When choosing a cutting tool, it is necessary to proceed from the processing method and type of machine, the shape and location of the surfaces being processed, the workpiece material and its mechanical properties.

The tool must ensure the required accuracy of shape and size, the required roughness of the machined surfaces, high productivity and durability, must be sufficiently durable, vibration-resistant, and economical.

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Figure 2 - End mill

The material of the cutting part of the tool is of utmost importance in achieving high machining productivity.

For surface milling, I choose an end attachment with mechanical fastening of pentagonal carbide plates (GOST 22085-76).

Cutter diameter, mm D = 100

Number of cutter teeth z = 12

Geometric parameters of the cutting part of the cutter

Main plan angle q = 67є

Auxiliary angle in plan ц1 = 5є

Main rake angle r = 5є

Main relief angle b = 10є

Angle of inclination of the main cutting edge l = 10°

Inclination angle of inclined or helical teeth = 10°

The material of the cutting part of the cutter is high-speed steel grade T15K6 in the form of a pentagonal plate.

To mill a groove, I choose a groove backed cutter (GOST 8543-71).

Grooving cutter

Cutter diameter D = 100

Number of cutter teeth z = 16

Hole diameter d = 32

Cutter width B = 10

The material of the cutting part of the cutter is VK6M hard alloy according to GOST (3882-88)

To drill a hole, I choose a standard twist drill equipped with hard alloy plates and a conical shank (GOST 2092-88)

Twist drill

Drill diameter in mm d = 35

Total drill length in mm L = 395

Drill length Lo = 275

Geometric sharpening parameters

apex angle 2ts = 120º

main rake angle r = 7є

main rear angle b = 19є

angle of inclination of the transverse edge w = 55º

the angle of inclination of the helical groove = 18º

vertex angle 2к0 = 73є

The material of the cutting part of the drill is high-speed steel grade T15K6 in the form of plates.

To grind the groove, I choose a straight profile cylindrical grinding wheel GOST 8692-82

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Figure 7 - Grinding wheel

Maximum outside diameter, mm D = 100

Circle height H = 10

Bore hole diameter d = 16

Hardness (GOST 18118-78) - medium-hard circle.

Grit size - 50.

Fifth ceramic bond.

2 The choice of measuring tool depends on the shape of the surfaces being measured, the required processing accuracy and the type of production.

To control the required accuracy of the processed surfaces, I choose the following measuring tool.

Vernier calipers (GOST 166-63).

Micrometric internal meter (GOST 10-58).

To control the roughness of the treated surface, I choose a type 240 profilometer (GOST 9504-60).

7 . Calculationmodescutting

1 Cutting depth t, mm, depends on the processing allowance and the required roughness class of the machined surface is less than 5 mm, then milling will be performed in one pass.

2 The feed amount is selected from reference literature depending on the mechanical properties of the material being processed, the cutting tool and the required surface roughness class.

On milling machines, the minute feed Sm, mm/min is adjusted, i.e. the speed of movement of the table with the fixed part relative to the cutter. The elements of the cut layer, and therefore the physical and mechanical parameters of the milling process, depend on the feed per tooth Sz, i.e. movement of the table with the part (in mm) during the rotation of the cutter by 1 tooth. The roughness of the machined surface depends on the feed per revolution of the cutter S0, mm/rev.

There is the following relationship between these three values:

where n and z are the rotation speed and the number of cutter teeth, respectively.

We take the feed value Sz from the reference literature

Then, using formula (2), we calculate SM

3 The estimated cutting speed is determined by the empirical formula

where Cv is the cutting speed coefficient, which depends on the materials of the cutting part of the tool and workpiece and on the processing conditions;

T - design life of the cutter, min;

m is an indicator of relative resistance;

Xv, Yv, Uv, pv, qv, - respectively, indicators of the degree of influence of cutting depth, feed, milling width, number of teeth and cutter diameter on cutting speed;

Kv - correction factor for changed conditions.

The meaning of the coefficient and exponents in the cutting speed formula for milling

Cv = 445; qv = 0.2;pv; Xv = 0.15; Yv = 0.35, nv = 0.2; pv =0; m = 0.32

The correction factor Kv is determined as the product of a number of coefficients

where Kmv is a coefficient that takes into account the influence of the mechanical properties of the material being processed on the cutting speed;

Kпv - coefficient taking into account the state of the workpiece surface;

Kiv - coefficient taking into account instrumental material.

Kпv = 0.8; Kiv = 1.

From formula (4) we find the correction factor:

Then, using formula (3), we find the estimated cutting speed

Spindle rotation speed, rpm is calculated using the formula

where Vp is the design cutting speed, m/min;

D - cutter diameter, mm.

Using formula (5) we find the estimated spindle speed

Now let’s calculate the actual rotation speed nf, the closest one from the machine’s passport data. To do this, let’s find cn and determine the entire series n

where nz and n1 are the maximum and minimum value rotation speed;

n is the number of rotation speed steps.

Now we determine from the geometric series

n2 = n1 cn = 31 1.261 = 39.091;

n3 = n1 c2n = 31 1.2612 = 49.294;

n4 = n1 c3n = 31 1.2613 = 62.159

n5 = n1 q4n = 31 1.2614 = 78.383

n6 = n1 q5n = 31 1.2615 =98.841

n4 = n1 c3n = 31 1.2613 = 124.638

n4 = n1 c3n = 31 1.2613 = 157.169

n4 = n1 c3n = 31 1.2613 = 198.19

n4 = n1 c3n = 31 1.2613 = 249.918

n4 = n1 c3n = 31 1.2613 = 315.147

n4 = n1 c3n = 31 1.2613 = 397.4

Thus nf = 315.147 rpm.

Now we can determine Vf using formula (7)

where D is the cutter diameter, mm;

nf - rotation speed, rpm.

4 We calculate the minute feed using the formula

Substituting the values into formula (8) we get

Let us determine the value of Sm, the nearest smaller one from the machine’s passport data: Sm = 249.65 mm/min

Let's determine the actual feed per tooth

Substituting the values into formula (9) we get

5 The cutting force during milling is determined by the empirical formula

where t is the milling depth;

Sz - actual feed, mm/tooth;

z - number of cutter teeth;

D - cutter diameter, mm

nf - actual cutter rotation speed rpm.

The values of the coefficient Cp and exponents Xp, Yp, Up, qp have the following meanings

Cp = 545; Xp = 0.9; Yp = 0.74; Up = 1; qp = 1.

The value of the correction factor Kp during milling depends on the quality of the material being processed.

Then we get

The power utilization factor of the machine is determined by the formula

where Ned is the power of the drive motor, kW;

Npot is the required power on the spindle, which is determined by the formula

where Ne is the effective cutting power, kW, determined by the formula

Substituting the value into formula (13) we get

Substituting the values into formula (12) we get

Now let's calculate the power utilization factor of the machine

The actual tool life Tf is calculated using the formula

Let's substitute the values into formula (14) and get

6 The time spent during the milling process is determined by the formula

where L is the estimated processing length, mm;

i - number of passes;

Sm - actual feed, mm/min;

The estimated processing length is determined by formula (16)

where l is the processing length, mm;

l1 - infeed value, mm;

l2 - cutter overtravel, mm.

The amount of infeed l1 is calculated by formula (17)

where t is the cutting depth, mm;

D - cutter diameter, mm.

We get

Let us take the overtravel l2 to be 4 mm.

Find the estimated processing length L:

Using formula (15) we calculate the main time

8 . Rationingtime,definitionpricesAndproduction costsmechanicalprocessingdetails

1 Piece time for machining one part is calculated by the formula

where t0 is the main technological time, min;

tв - auxiliary time, min;

tob - time of organizational and technical maintenance of the workplace, min;

tf - time of breaks for rest and physical needs, min.

The main technological time is equal to the sum of the machine time values for all transitions of a given operation.

Thus we get

where t01, t02, t03 is the main time for processing each surface, which we calculate from the proportion

From proportion (20) we obtain

Find t0i

t01 = 0.00456 100 = 0.456 min

t02 = 0.00456 100 = 0.456 min

t03 = 0.00456 100 = 0.456 min

Using formula (19) we calculate Уt0:

Auxiliary time - time for installation, securing and removing the part, supplying and withdrawing tools, turning on the machine, checking dimensions.

Using the literature we get

Time for organizational and Maintenance workplace tob includes: time for adjustment, cleaning and lubrication of the machine, for receiving and laying out tools, changing dull tools, etc.

Time for servicing the workplace tob, as well as for rest and physical needs tf are assigned to the operation and calculated using the formula

where b is the percentage for workplace maintenance;

c - percentage for rest and physical needs.

Using formula (21) we obtain

Thus, now using formula (18) we can calculate tpc

2 Piece-calculation time for an operation is calculated using formula (22)

where tпз is the preparatory and final time for the entire batch of parts, min;

n is the number of parts in the batch.

3 This time is determined as a whole for the operation and includes the time spent by the worker on familiarizing himself with the technological map for processing the part, studying the drawing, setting up the machine, obtaining, preparing, installing and removing the device to perform this operation.

In accordance with the literature, the preparatory and final time is taken to be 30 minutes.

4 The price for work performed, that is, the cost of labor P is determined by formula (23)

where Ct is the tariff rate of the corresponding category;

K - coefficient.

The value of the tariff rate corresponding to category 4 is taken equal to

St = 247.64 rub/h

We take the coefficient K equal to 2.15.

Thus, using formula (23) we obtain

5 The cost of machining parts C includes the cost of labor P and the cost of overhead costs H and is determined by formula (24)

where N is the cost of overhead costs, rub.;

P - cost of labor, rub.

The cost of overhead costs is taken equal to 1000% of the cost of labor

Using formula (25) we find H

Thus, we calculate the cost of machining

9 . Constructiondevices

The objective of the course work is to develop the design of one device included in the technological equipment of the designed machining process.

Machine tools are designed for installation and fastening of the workpiece and are divided: according to the degree of specialization - into universal, reconfigurable, prefabricated from normalized parts and assemblies; according to the degree of mechanization - manual, mechanized, automatic; by purpose - for devices for turning, drilling, milling, grinding and other machines; by design - single and multi-seat, single and multi-position.

The choice of the type of fixture depends on the type of production, the part production program, the shape and size of the workpiece and the required processing accuracy.

When designing a machine tool, the following main tasks are solved:

1) elimination of a labor-intensive operation - marking parts before processing;

2) reduction of auxiliary time for installation, fastening and reinstallation of the part relative to the tool;

3) increasing processing accuracy;

reduction of machine and auxiliary time due to simultaneous processing of several parts or combined processing with several tools;

facilitating the worker’s work and reducing the labor intensity of processing;

increasing technological capabilities and specialization of the machine

As a result of using the device, productivity should increase significantly and the cost of processing will decrease.

As a device for milling, we choose a machine vice GOST 18684-73, in which the clamping jaws have been modernized. This modernization helps ease the work of workers.

10. Decortechnicaldocumentation

The main document of the technical documentation is a route map, which indicates all operations and transitions, as well as equipment, fixtures, cutting and measuring tools, and the number of workers.

The profile and dimensions are indicated.

The second technological document is the operating card. It indicates the transitions to one operation, its number and the material of the workpiece, its mass and the hardness of the part. For all transitions, a cutting and measuring tool is specified.

In addition, the design dimensions, depth of cut, number of passes, spindle speeds and speed of processing modes were calculated. Machine and auxiliary time was calculated.

11 . BasicintelligenceOtechnologysecurityatworkonmetal-cuttingmachines

Safety precautions cover a set of technical devices and rules that ensure normal human life during the labor process and exclude occupational injuries. When working on metal-cutting machines, the worker must be protected from exposure electric current, from impacts from moving parts of the machine, as well as from workpieces or cutting tools due to their weak fastening or breakage, from detached chips, from exposure to dust and coolant.

General safety rules when working on metal-cutting machines

1 TO independent work Persons who have passed a medical examination, completed introductory briefing, initial briefing at the workplace, and have a labor protection certificate are allowed.

2. Perform only work within the scope of duties.

3. Work only in working order, neatly tucked in overalls and safety shoes, as provided for in the labor protection instructions.

4. Use only serviceable devices, equipment, tools, and use them for their intended purpose.

5. Do not leave switched on (working) machines and mechanisms and equipment unattended.

When leaving, even for a short time, disconnect it from the power supply using the mains switch.

6. Do not walk under a raised load.

7. Do not wash workwear in kerosene, gasoline, solvents, emulsions, and do not wash your hands in them.

8. Do not touch live parts of electrical equipment of machines and mechanisms, workpieces and parts being processed when they are rotating.

9. Do not blow compressed air parts, do not use compressed air to remove chips.

10. Use at work wooden flooring and keep it in good condition and clean.

11. Main dangerous and harmful production factors:

possibility of electric shock;

the possibility of burns and mechanical damage from chips;

increased noise level;

possibility of falling of installed and processed parts and workpieces.

12. When working on machines, the use of gloves or mittens is not permissible.

Safety requirements upon completion of work.

1. Turn off the machine and disconnect the electrical equipment.

2. Tidy up the workplace.

3. Wipe and lubricate the rubbing parts of the machine.

4. Clean up spilled oil and emulsion by sprinkling sand on the contaminated areas.

5. Remove shavings and dust using a broom brush.

6. Rags used during cleaning and work, take the rags outside the workshop to places designated for this purpose.

7. When handing over a shift, inform the foreman and shift worker about any deficiencies noticed and measures taken to eliminate them.

8. Wash your face and hands with warm water and soap or take a shower.

Technique security at work on screw-cutting lathe machine.

1. Before turning on the machine, you must make sure that its start-up is not dangerous for people near the machine.

3. Ensure reliable fastening of the part.

4. When processing parts on centers, do not use centers with worn cones.

7. It is prohibited to touch the rotating parts of the machine with your hands, as well as the workpiece.

8. To avoid clothing being caught by rotating parts, you must carefully tuck in your overalls and tuck your hair under your headdress.

9. It is prohibited to clean, lubricate, install or remove parts while the machine is operating.

10. Access to the electrical cabinet and the workplace should not be cluttered.

11. If you receive an injury, you must notify the site foreman or workshop manager.

12. Attention!

To avoid overheating of the motor, it is not allowed to make more than 60 starts per hour at spindle revolutions per minute up to 250, no more than 30 starts per hour at revolutions above 250 per minute and no more than 6 starts per hour at spindle speeds 750 per minute.

Bibliography

1. Handbook of mechanical engineering technologist: In 2 vols. T. /Ed. Kosilova A.G. and Meshcheryakova R.K. M., 1972.-694 p. T. 2 /Ed. Malova A.N. - M.: 1972. - 568 p.

2. Fedin A.P. Materials science and technology of materials: (Guidelines and assignments for tests). - Gomel: BelGUT.-1992.-83 p.

3. Zobnin N.P. and others. Processing of metals by cutting. - M.: All-Union Publishing and Printing Association of the Ministry of Railways, 1962. - 299 p.

Lakhtin Yu.M., Leontyeva V.P. Materials Science.-M., 1990.-528 p.

Metalhead's Handbook. T. 5/. /Ed. B.L. Boguslavsky. -M.: Mechanical Engineering, 1997. -673 p.

Masterov V.A., Berkovsky V.S. Theory of plastic deformation and metal forming. -M.: Metallurgy, 1989.400 p.

Kazachenko V.P., Savenko A.N., Tereshko Yu.D. Materials science and technology of materials. Part III. Processing of metals by cutting: A manual for course design. - Gomel: BelGUT. 1997.-47p.

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2. Technological analysis of the working drawing of the part

Technological analysis of the working drawing of a part (or the part itself) is carried out in the following two directions:

1) testing of part designs for manufacturability;

2) analysis of the actual technological properties of the part.

Testing of designs for manufacturability is carried out jointly by design and technological services at the product design stage. The main task Such development is reduced to giving the shapes, overall dimensions, and methods of producing workpieces the most acceptable and economical indicators (characteristics) for the given conditions. Testing of designs for manufacturability is carried out until the product is put into mass production. All costs associated with improving designs at the stage of testing them for manufacturability are attributed to the prototype product samples (parts).

In justified cases, during such development, geometric shapes are simplified and complex ones are given structural elements simpler forms with a focus on mechanical processing on universal equipment.

Manufacturability is a conditional concept, since the same design, for example stamping, is certainly technologically advanced in mass production and is not at all technologically advanced when producing parts in single samples, etc.

An important indicator of the manufacturability of a part’s design is the orientation of setting the linear dimensions of chains to specific conditions of production and use to ensure their accuracy using certain methods. When testing for manufacturability, in some cases the limiting dimensions (deviations) are technologically tightened to create better conditions for basing the workpieces during machining.

The technological properties of parts are analyzed based on the physical and mechanical properties of the material and design and technological parameters.

Among the physical and mechanical properties of materials, plasticity, surface and general hardness, condition of the workpiece, etc. are considered. Plastic or brittle materials determine the almost unambiguous choice of cutting tool material, especially for hard alloys. When processing plastic materials, for example, steels, more productive, but less durable titanium-tungsten-cobalt alloys of the TK type (T5K10, T5K6, etc.) are used. On the contrary, for processing brittle alloys (cast iron, etc.), more durable hard alloys of the tungsten-cobalt group of the VK type (VK3, VK6, etc.) are used.

When performing technological analysis of design and technological characteristics, the following is optimized:

1) dimensional accuracy parameters (accuracy grades of external surfaces and holes, dimensions with and without maximum deviations);

2) microrelief parameters (intervals of changes in microrelief parameters of external surfaces and holes, surfaces with different hardness values);

3) deviations of the processed surfaces from the shape and deviations in the relative position of the base surfaces.

In this analysis, attention is focused on the influence that each of these characteristics (parameters) has on the structure and content of the technological process of mechanical processing.

3. Structure and design of the technological process

Any technological process of machining of workpieces is structurally composed of routing and operational technologies. The most detailed is operating technology. It includes technological operations. Among the main components of technological operations are installations and technological transitions. Installations are part of a technological operation performed with one constant fixation of the workpiece.

In accordance with the Unified System of Technological Documentation (USTD) full set technological documents includes a large number of standard forms (maps). In practical design, the type and number of technological maps depends on specific production conditions and is determined by standards.

A route technological process is an enlarged description of the sequence and content of technological operations that are performed to transform a workpiece into a finished part.

The operational technological process is drawn up on special operational cards. Unlike route technology, operational technological maps provide a detailed record of the sequence of processing of each individual surface with details of all the necessary technological information.

A sketch map (operational technological drawing) is graphic image parts in the form in which they “come out” of a given operation after processing.

The following information and symbols are indicated on the operational drawing:

1) processed surfaces with thicker lines; serial numbers of these surfaces; Moreover, if all designated surfaces are processed with the same tool at the same cutting modes, then the operational flow chart will contain exactly as many main transitions as the number of processed surfaces;

2) all accuracy parameters of the processed surfaces: accuracy standards and microrelief parameters are required, if necessary - accuracy of shapes and relative position;

3) base surfaces (their graphic representation is standardized).

Sketch maps in technological processes are developed for each technological operation.

4. Methodology for developing operational technology for machining

The following factors influence the choice of the machining sequence of a part:

1) nature of production;

2) requirements for the quality of the finished part in terms of accuracy parameters, condition and physical and mechanical properties of the processed surface layer.

In a single production, technological operations include a large number of installations and transitions for processing many external and internal surfaces. All this requires frequent changes and adjustments of tools, expenditure of auxiliary time, etc.

In serial production technological processes designed for special machines, the operations of the same name are differentiated and can consist of one auxiliary and one main transition. There are no part reinstallations in one operation, tool changes are minimized, and time spent on tool adjustment is reduced.

When assessing the influence of the requirements for the quality of the finished part on the construction of the technological process, one can tentatively be guided by the following:

1) any technological process must be repaired structural diagram(Fig. 1);

2) the stages of the technical process are interconnected with accuracy parameters and processing methods;

3)increasing surface hardness to HRC 35 above requires a transition from processing with a blade tool to abrasive processing;

4) sets of centering tools when processing holes are taken in accordance with the parameters of surface accuracy.

Figure 1. Block diagram of the technological process for manufacturing parts

Table 1. Relationship between technological stages and accuracy parameters when processing external surfaces with a blade or abrasive tool

Stage No.		Accuracy options
		Quality	Microrelief, microns			Blade	Abrasive
			Rz		Ra
000	Blank	According to GOST for blanks
005
010		14		80	Grind first
015	Heat treatment: annealing to relieve internal stress
020	Semi-finish machining	11		20	Grind
025
030	Finish machining at surface hardness:
	HB = 120 – 180	9		2,5	Grind clean (finally)
		9 and 7		1,25	Grind clean (preliminarily)
	HRC = 40	9		2,5
		9 and 7		1,25	Pre-grind Grind completely

Table 2. Relationship between technological stages and accuracy parameters when processing internal surfaces with a blade or abrasive tool

Stage No.	Name and content of the stage	Accuracy options			Technological transition during tool processing
		Quality	Microrelief, microns		Blade		Abrasive
			Rz	Ra	center	off-center
000	Blank	According to GOST for blanks
005	Heat treatment: annealing to relieve internal stress
010	Rough machining	14	80	Drill	Waste
015	Heat treatment: annealing to relieve internal stress
020	Semi-finish mechanical	11	20	Drill Countersink	Waste
025	Heat treatment to improve the physical and mechanical properties of parts in accordance with the instructions in the drawing
030	Finish mechanical at surface hardness:
	HB = 120 – 180	9	2,5	Drill Countersink Expand	Bore clean (finally)
		9 and 7	1,25	Drill Countersink Expand preliminary Expand final
	HRC = 40	9	2,5	Sand clean (finally)
9 and 7		1,25	Pre-grind Grind completely

5. Cutting modes and standardization of the technological process (operations)

The cutting modes include cutting depth t mm, tool feed S mm/rev (mm/min), cutting speed V m/min, cutting power kW.

Cutting modes are the basis for standardizing technological operations, selecting equipment and setting up the machine to perform a specific technological transition.

Cutting modes are determined by calculation or assigned according to tables.

The theoretical calculation of cutting conditions is more rigorous. However, empirical calculated dependencies rather give a better idea of the nature of the interaction various factors than quantitative estimates. Therefore, theoretical calculations are used extremely rarely in practical applications.

Assigning cutting modes using tables is simple and accessible to the user even with little experience in process design.

The assignment of cutting modes is preceded by the choice of workpiece material and tool material.

The choice of workpiece material is almost unambiguously predetermined by the working drawing of the part.

Among the tool materials in modern metalworking, carbon alloy tool steels, hard alloys and superhard tool materials are used.

In mechanical engineering, up to 70% of mechanical processing involves processing with blade tools made of hard alloys. All hard alloys, in accordance with the recommendations of international standards organizations, depending on the materials for which they are intended for processing, are divided into the following three groups:

1)P – for processing carbon, low-alloy and medium-alloy steels; these are alloys of the titanium-tungsten-cobalt group such as T5K10, T15K6, etc.; they differ increased wear resistance with relatively lower mechanical strength and allow cutting speeds of up to 250 m/min;

2)K – for processing materials with loose chips, such as cast iron, etc.; these are alloys of the tungsten-cobalt group of the VK type; they are more durable, but less wear-resistant;

3)M – hard alloys for processing special alloys.

When assigning modes, determine:

1) cutting as the difference between the dimensions of the machined surface on the previous one on the transition being performed according to operational sketches;

2) tool feed during turning, drilling, countersinking, reaming and grinding, depending on the type of processing: roughing, semi-finishing, finishing;

3) cutting speed according to tables.

It must be borne in mind that the cutting speed depends on the durability of the tool material and is, as it were, imaginary for the operator. The spindle speed of the machine is always important for the operator, since the machine can be set to a specific spindle speed, and not the cutting speed.

Therefore, the accepted cutting speed is recalculated to the spindle speed n according to the formula

where D is the diameter of the machined surface or center tool, mm.

Standardization of the technological process comes down to determining the time required to perform each individual operation, and, if necessary, the entire technological process.

Based on the time required to complete each operation, calculate wages core production workers.

In unit production, time costs are estimated using the so-called piece-calculation time Tpc.k.. This time is calculated using the formula

where Тп.з – preparatory and final time for performing the technological operation; it is provided for familiarization with working drawings, the technological process and setting up the machine;

m – number of parts in the batch being processed;

Tsht. – piece time for performing a technological operation.

In mass production, the number of processed parts is large and, therefore, Tp.z./m─>0 and Tpc.k.= Tpc.

Piece time is determined as a whole for a technological operation according to the expression:

where TO is the main time for performing a technological operation,

TV – auxiliary time for performing a technological operation,

K= (1.03 – 1.10) – coefficient that takes into account the time spent on organizational and technical maintenance of the machine and rest.

The main time is determined for each main transition, and the auxiliary time is determined for all transitions (main and auxiliary).

The main time is the time spent directly on cutting. For all types of machining:

where Ar is the estimated length of the processed surface.

Auxiliary time is assigned according to standards in the form of the sum of individual components, namely:

where tset is the time for installing and removing the part, taken into account once per operation, if there are no reinstallations of the workpiece,

tpr – time associated with the implementation of the main technological transition; it is provided for the supply (retraction) of a tool, turning on (turning off) the machine, etc.; is taken into account as many times as the main transitions in the operation;

tn and ts – respectively, the time for changing the spindle (tool) speed and tool (workpiece) feed;

tmeas – time for measurements, taken into account for each processed (measured) surface;

tcm – time for tool change, time for initial installation (adjustment) of the tool is included in tpr of the first main technological transition;

tvs – time to withdraw the drill to remove chips; are provided only when drilling holes in solid workpieces.

In course work we conditionally accept:

tset = 1.2 min., tpr = 0.8-1.5 min., (larger values for semi-finishing transitions, and smaller values for rough transitions), tn = ts = 0.05 min., tmeas = 0.08 – 1.2 min. (larger values for calibers, smaller values for a universal measuring instrument), tcm = 0.10 min, tvs = 0.07.

shaft processing part technological

Table 3. Calculation of time spent on performing a technological operation

Numbers				Main time, min
Operations		Transition				mouth			tpr			tn		ts			tism		tcm
05		1(A)		-		1,2			-			-		-			-		-
		2		0,02		-			0,8			-		-			0,1		-
		3		0,03		-			0,8			0,05		0,05			-		0,1
To = 0.05 min. TV = 3.1 min. Tsht = 1.05(To + Tv) = 1.05(0.05 + 3.1) = 3.31 min.
010		1(A)		-		1,2			-			-		-			-		-
		2		0,29		-			-			-		-			-		-
To = 0.29 min. TV = 1.2 min. Tsht = 1.05(To + Tv) = 1.05(0.29 + 1.2) = 1.56 min.
015		1(A)		-		1,2			-			-		-			-		-
		1		0,47		-			-			-		-			-		-
To = 0.47 min. TV = 1.2 min. Tsht = 1.05(To + Tv) = 1.05(0.47 + 1.2) = 1.75 min.
025		1(A)		-		1,2			-			-		-			-		-
		2		0,32		-			1,0			-		-			-		-
		3		0,10		-			1,0			-		0,05			-		0,1
		4		0,04		-			1,0			0,05		-			-		-
		5		0,48		-			1,0			0,05		0,05			0,1		0,1
		6		-			1,0			-		-			0,1		-
		7		0,20		-			1,0			-		0,05			-		-
That = 1.14 min. TV = 7.85 min. Tsht = 1.05 (To + Tv) = 1.05 (1.14 + 7.85) = 9.44 min.
030		1(A)		-		1,2			-			-		-			-		-
		2		0,02		-			1,0			-		-			0,1		-
		3		0,16		-			1,0			0,05		-			0,1		-
		4		0,20		-			1,0			0,05		-			0,1		-
		5		1,1		-			1,0			-		-			0,5		0,1
		6		0,04		-			1,0			0,05		-			0,5		0,1
		7		0,07		-			1,0			-		-			0,5		-
		8		0,05		-			1,0			0,05		-			0,5		-
		9		-		-			1,0			-		-			0,5		-
To = 1.64 min. TV = 10.15 min. Tsht = 1.05(To + Tv) = 1.05(1.64 + 10.15) = 12.38 min.
040		1(A)		-		1,2			-			-		-			-		-
		2		2,0		-			1,5			-		-			0,2		-
To = 2.0 min. TV = 2.9 min. Tsht = 1.05(To + Tv) = 1.05(2.0 + 2.9) = 5.15 min.
045		1(A)		-		1,2			-			-		-			-		-
		2		0,5		-			-			-		-			0,2		-
		3		0,5		-			-			-		-			0,2		-
		4		0,5		-			-			-		-			0,2		-
Then = 1.5 min. TV = 1.8 min. Tsht = 1.05(To + Tv) = 1.05(1.5 + 1.8) = 3.47 min.
050		1(A)		-		1,2			-			-		-			-		-
		2		0,48		-			1,5			-		-			0,2		-
To = 0.48 min. TV = 2.9 min. Tsht = 1.05(To + Tv) = 1.05(0.48 + 2.9) = 3.55 min.
Numbers			S, mm/rev		n, rpm		Main time T0, min	Auxiliary time TV, min
Operations	Transition							mouth		tpr	tsun		tn		ts	tism		tcm
																		instr.		cond. bushings
055	1(A)		-		-		-	1,2		-	-		-		-	-		-		-
	2		0,3		630		0,11	-		1,5	0,07		-		-	-		-		-
	3		0,8		630		0,04	-		1,5	-		0,05		0,05	-		0,1		0,1
	4		1,0		250		0,08	-		1,5	-		0,05		0,05	0,2		0,1		0,1
	5		-		-		-	-		1,5	-		-		-	-		0,1		0,1
To = 0.23 min. TV = 8.27 min. Tsht = 1.05(To + Tv) = 1.05(0.23 + 8.27) = 8.93 min.

6. Calculation of dimensional chains

Calculation of dimensional chains when replacing the closing dimension

A type of recalculation of a dimensional chain in which, regardless of the recalculation sequence, the accuracy of the A6 size will be ensured automatically.

Figure 2. Diagram of the dimensional chain when replacing the closing link

The calculation is performed in tabular form.

Calculation of tolerances of component dimensions in technological dimensional chains
Dimensions				Distribution
Designation	Meaning			Uniform		Same quality TA6 = 0.4; ast = 40 µm.
Designation	Meaning			TAi = =TA6/m	TAik/ /TAi	Size range, mm	Aisr, mm			TAI, mm	TAik/ /TAi
A1	30	-0,45	0,45	0,07	6,4	18 - 30	24	2,88	1,13	0,05	9
A2	200	-0,5	0,50	0,07	7,1	180 - 250	215	5,99	2,70	0,12	4
A3	25	+0,2	0,20	0,07	2,9	18 - 30	24	2,88	1,13	0,05	4
A4	45	+0,4	0,40	0,07	5,7	30 - 50	40	3,42	1,54	0,06	7
A5	25	+0,25	0,25	0,07	3,6	18 - 30	24	2,88	1,13	0,05	5
A6	5	+0,2	0,40	-	-	-	-	-	-	-	-
AT	70	-	-	0,05	-	50 - 80	65	4,02	1,81	0,07	-

TAi1=1.13*0.4/9.44=0.05 TAik1/ TAi1=0.45/0.05=9

TAi2=2.70*0.4/9.44=0.12 TAik2/ TAi2=0.50/0.12=4

TAi3=1.13*0.4/9.44=0.05 TAik3/ TAi3=0.20/0.05=4

TAi4=1.54*0.4/9.44=0.06 TAik4/ TAi4=0.40/0.06=7

TAi5=1.13*0.4/9.44=0.05 TAik5/ TAi5=0.25/0.05=5

TAit=1.81*0.4/9.44=0.07

Analysis of the results obtained shows that changing the linear dimensional chain for technological reasons leads to a tightening of their values from 2 to 6 times.

Calculation of the dimensional chain using the “maximum – minimum” method

In some cases, for example, when preparing to assemble mating parts, it may be advisable to evaluate possible fluctuations in the closing size. This assessment is carried out by calculating the dimensional chain, which includes the closing dimension, using the maximum deviations using the “maximum – minimum” method.

Figure 3. Diagram of the dimensional chain when calculating the closing link

A0, es(A0) and ei(A0) – size, upper and lower, respectively maximum deviation closing link;

Auv, es(Auv) and ei(Auv) – respectively the size, upper and lower maximum deviation of the increasing size;

Aium, es(Aium) and ei(Aium) – respectively the size, upper and lower maximum deviation of the reducing dimensions;

A2 = Auv = 200; es(Auv) = 0; ei(Auv) = -0.5;

A1 = A1um = 30; es(A1um) = 0; ei(A1um) = -0.45;

A6 = A6um = 5; es(A6um) = 0.2; ei(A6um) = -0.2;

A5 = A5um = 25; es(A5um) = 0.25; ei(A5um) = 0;

A4 = A4um = 45; es(A4um) = 0.4; ei(A4um) = 0;

A3 = A3um = 25; es(A3um) = 0.2; ei(A3um) = 0;

TAuv = 0.5; TA1um = 0.45; TA6um = 0.4; TA5um = 0.25; TA4um = 0.4; TA3um = 0.2;

1) Nominal size of closing link:

2) Upper limit deviation:

3) Lower limit deviation:

4) Closing dimension tolerance:

5) The tolerance is also determined:

The conversion was done correctly.

7. Technological process mechanical processing of the end shaft

Material		Mass details
Name, brand			View	Profile
Steel 35		Stamping
operations	Name and content of the operation			Equipment	Device and tool	Tp.z.
						Tsht
000	Procurement Blank stamping
005	Turning. End trimming. End alignment			Turning 1K62	3 jaw chuck. Passable cutter. Centering drill.	3,02
010	CNC turning. Preliminary. Treatment of external surfaces.			CNC lathe 1K20F3S5	Clamping special Passable cutter.	6,41
015	CNC turning. Trimming the end, processing the outer surface of the flange.			CNC lathe 1K20F3S5	Special clamping. Passable cutter.	5,71
020	Thermal. Annealing to relieve internal stress.			Special
025	Turning. Semi-finish processing of external and internal surfaces.			Turning 1K62	3 jaw chuck. Spiral drill, boring cutter, through cutter.	1,06
030	Turning. Semi-finishing of external surfaces			Turning 1K62	3 jaw chuck. Center. rotating. Groove cutter, through cutter.	0,81
035	Chemical-thermal. Cementation. Hardening.			Special.
040	Internal grinding. Final grinding of the hole.			Grinding 3A240	Special round grinding device.	1,94
045	Cylindrical grinding. Final sanding of external surfaces.			Grinding 3152	Collet mandrel, center. rotate cylindrical grinder	2,88
050	Vertical drilling. Tapping a hole in a shaft flange.			Vertical drilling machine 2A125	Clamping device. Machine tap.	2,82
055	Radial drilling. Machining holes on the shaft flange			Radial drilling machine 2A53	Conductor special invoice. Drill, countersink, reamer.	1,12
060	Test. Final inspection of the part according to the drawing.

15,5/1250*0,5=0,025 ;

10/2000*0,2=0,025

25/2000*0,5=0,03;

45/1600*0,5=0,06;

25/1250*0,5=0,04;

70/1000*0,5=0,14;

32/400*0,5=0,16;

60/400*0,5=0,3;

38/400*0,3=0,32;

0,5/1000*0,3=0,10;

20/1000*0,5=0,04;

60/500*0,25=0,48;

31/630*0,25=0,20

5/1000*0,25=0,02;

25/630*0,25=0,16;

80/1600*0,25=0,20;

25/2500*0,25=0,04;

45/2500*0,25=0,07

25/2000*0,25=0,05;

Table 4. Commentary on the technological process of machining

Structure	Content
Route technology	Route technology, just like operational technology, is drawn up on standard technological maps. To methodically simplify educational design in technological maps, a number of columns that do not contain fundamentally important information are not filled out or marked. The route technological process is built in accordance with the recommendations of the guidelines on the influence of the requirements for the quality of parts on the structure of the technical process, namely: it includes the stages of preliminary, semi-finishing and final (finishing) processing. In the technological process (in route maps), we take the preparatory and final time equal to zero (corresponds to the conditions of mass production) and do not indicate it in the maps.
Operation 000	The blanking operation is designed with a focus on mass production and for this reason stamping is selected as the blank. Allowances for machining are taken in such a way that they can be removed in pre-processing operations in one pass. This is perfectly acceptable for educational purposes. In practice, the dimensions of the workpieces are taken taking into account those allowances recommended by the regulatory tables. Here the following numerical values of allowances were established: for preliminary processing - 2.5 mm, semi-finishing - 0.75 mm and final (grinding) - 0.25 mm per side. Naturally, such allowances clearly determine the dimensions of the workpiece. The maximum stamping dimensions were set according to a typical stamping method: the upper limit plus (deviation for die wear) is always larger, the lower limit minus (for understamping) is always smaller. In addition, on the stamping technological drawing, the nominal dimensions of the surfaces of the finished part are indicated in brackets.
Operation 005	Designed to create an installation base in the form of a center hole. Such holes are processed technologically even in cases where they are not indicated in the drawing (except for specially specified requirements).
Operation 010	The design of the part is quite technologically advanced for the use of a CNC machine. The peculiarity of its design is that in order to bring the dimensional chain to an absolute coordinate system, it was necessary to transform the design dimensional chain into a technological one. The control program was developed according to a standard algorithm. Since all processing is provided for in the program, when calculating the cost of auxiliary time, only the time for installing and removing the part was taken into account. The rotation speeds of the machine spindle were optimized according to the diameters of the workpiece steps, bringing them to standard values.
Operation 015	The operation is similar to the previous one on a CNC machine. As in operation 010, control transitions were not provided, since work according to the control program is limited to periodic monitoring of the machine settings.
Operation 020	Thermal. It does not require any special comments, and its purpose is clear from the technological map. The content of this heat treatment is determined according to the technological processes of the chief metallurgist of the enterprise.
Operation 025	We begin semi-finishing by creating a further convenient installation base in the form of a hole. This is also justified by the fact that according to the drawing relative to the axis of the hole, technical requirements for the radial runout of one of the outer surfaces are specified. Cutting speeds during transverse turning and boring, if necessary, can be adjusted according to the cutting speed during longitudinal cutting by introducing a coefficient of 0.8-0.9.
Operation 030	Semi-finish processing of external surfaces. For now, no special precision is required. In practice, all other things being equal, such basing is always more economical. We reduce the preparation of the part for final processing to cutting technological grooves for the exit of the grinding wheel during finishing processing.
Operation 035	We include this operation in the technical process at the request of the designer (working drawing). Let us pay attention to some features of this chemical-thermal operation, namely: 1) it serves to increase the surface hardness to such numerical values at which further mechanical processing with a blade tool becomes impossible and a transition to grinding is required; 2) as can be seen, the surface is saturated with carbon to a certain depth; this depth is controlled by the fractures of the samples, the so-called witnesses, which are specially made simultaneously with the processing of the workpiece. If necessary, microstructure can be determined from these samples. When carburizing, surfaces that are not indicated in the drawing and do not require increased hardness are protected in a special way before chemical-thermal treatment.
Operation 040	Final processing by grinding the seat belt. Based on mass production, a plug gauge is used as a measuring tool.
Operation 045	Final (finishing) processing of external surfaces. The location is unconditional on the internal hole with compression by the rear rotating center to increase the rigidity of the technological system. Since the length of the processed surfaces is small, grinding is performed by plunging. The dimensions are controlled with clamp gauges.
Operation 050	Does not require any special comments.
Operation 055	We provide for the processing of holes on a radial drilling machine in a special jig to eliminate marking operations from the technical process and ensure the specified accuracy in the location of holes. We accept the set of centering tools according to the recommendations of the guidelines. Control of hole accuracy using plug gauges.

Bibliography

1. Sumerkin Yu.V. Fundamentals of mechanical engineering technology (course work) - St. Petersburg; SPGUVK, 2002

2. Sumerkin Yu.V. Fundamentals of ship mechanical engineering technology: Textbook - St. Petersburg; SPGUVK, 2001 – 240 p.

The technological process is part production process, containing a consistent change in the size, shape, appearance of the item of production, and their control.

Process elements: operation, installation, position, processing, transition, passage, working technique, movement.

A technological process is usually divided into parts called operations.

Operation represents a completed part of the technological process. O. is designed to change geometric and physical parameters products for 1 work place with 1 worker.

Operation performed continuously at one workplace.

An operation is the basic unit of production planning and accounting. At the beginning of the operations, the labor intensity of manufacturing parts is determined, time standards and prices are set, the required number of equipment, fixtures and tools is set, and processing is determined.

Composition O.: AIDS: machine, device, tool, part.

Installation- this is the determination of the position of the workpiece on the machine using machine tools.

In order to be able to represent the structure of the operation and take into account the time spent on its execution, it was necessary to divide the operation into separate parts, called transitions.

Position– this is a fixed position occupied by the fixed workpiece together with the fixture relative to the tool. (revolving lathes with horizontal and vertical axis of rotation of the head.)

Treatment. The goals of fur processing are changing the properties, geometric characteristics, and dimensions of the workpiece.

Technological transition– this is the mechanical processing of one or more repeated workpieces, with one or more tools, under constant technological conditions and installation.

In accordance with this, the transition directly related to the implementation of technological impact is called the main one (drilling). A transition consisting of the actions of a worker or mechanisms necessary to complete the main transition is called auxiliary (installation and fastening of a part).

Passage – processing of individual surfaces with the same installation of the work piece.

Working stroke called a single relative movement of the tool and the workpiece, as a result of which one layer of material is removed from its surface. To be able to process a workpiece, it must be installed and secured in a fixture on the machine table. Each new fixed position of a production object, together with the device in which the object is installed and secured, is called a working position.

Movement - This individual actions machine (turning on, turning off).

A working technique is a complete set of human actions when performing a certain part of an operation, used when performing a transition or part of it. For example - turn on the machine, switch feeds, etc.

The reception is part of the auxiliary transition.

Types of production

There are three types of production: I/mass, 2/serial, 3/single.

Single: Single production is called production characterized by a small volume of production of identical products, repeated production of products, which, as a rule, are not provided for. There is no cyclical production characteristic of mass production.

The lack of repeatability of manufacturing leads to the search for the most simplified ways to manufacture products. Most often, experimental, repair shops, etc. work this way. The workers here are like

usually highly qualified. Equipment and accessories are universal. The cost of production is high.

1. breadth of the range of manufactured products 2. small volume of their production, tens of pieces per year. 3. universal coverage of various types of products. 4. flexibility in terms of the use of universal equipment (for example, a screw-cutting lathe, a standard cutting or measuring tool)5. The technological process of manufacturing a part has a compacted character, i.e. several operations or complete processing of the manufactured product are performed on one machine 6. C/c is relatively high 7. worker qualifications – 5 – 6 category, high. 8 machine – universal, precision equipment. 9. The coefficient has consolidated operations of more than 40. 10. A simplified documentation system is used. 11. There are no technical standards; experimental and statistical labor standardization is used. 12. billets: hot rolling, earth casting, forgings

Serial: (small-, medium-, large-scale - depends on the V batch)

small-scale: 1. qualification slave 5-6 category, 2. satnki - semi-automatic machines 3. coefficient of fastening the operation 20 - 40

medium: 1. qualification slave 4th category, 2. satnki - semi-automatic machines 3. coefficient of fastening operation 10-20

large-scale production: 1. qualification slave 3rd category, 2. automatic. Satnki, production modules 3. operation fastening coefficient from 1-10

1. a limited range of products is manufactured in periodically repeating batches 2. the output volume is greater than in a single production, periodically in repeating batches 3. blanks - hot and cold rolled, injection molding, casting, stamping 4. The technological process is predominantly differentiated , i.e. divided into departments operations performed on a specific machines 5. when choosing technological equipment (using auxiliary, special devices), it is necessary to calculate costs and payback periods, as well as liquefied eq. Effect. 6. c/c lower than in a single production

Bulk:

Massive - production characterized by a large volume of product output continuously

manufactured or repaired over a long period of time, during which one work operation is performed at most workplaces. In mass production for each operation

the most productive, expensive equipment /automatic, semi-automatic/ is selected, the workplace is equipped with complex, high-performance devices and devices, in

As a result, with a large volume of product output, the lowest production cost is achieved.

1. coefficient fixed =1. 2. qualification 3-4 (1 repetitive operation is performed at each workplace) 3. automatic. satnki, production modules. 4 in-line production 5. the required accuracy is achieved by methods of automatically obtaining dimensions on customized machines.

1.narrow range of products. 2. large volume of product output, continuously produced during the current period. long period of time 3. The technological process is developed in detail, which is characterized by low labor intensity and low compared to serial production of s/c products. 4. the use of mechanization and automation of industrial processes. 5. use of technology. process with elementary operations. 6. use of high-speed specials. devices, as well as cutting and measuring instruments. 7. Use the template

Surface quality

The quality of a surface is the totality of all its service properties and, first of all, wear resistance, corrosion resistance, fatigue strength, as well as some other properties. Surface quality is assessed by two parameters:

Physical characteristics;

Geometric characteristics

Geometric characteristics are the parameters of the deviation of a surface from an ideal, specified one. The surface can be non-flat, oval, cut, etc. The surface can be depicted in an enlarged form as a wavy line.

Geom. The quality characteristics of the processed surface are determined by the deviation of the real surface from the nominal one. These deviations can be divided into 3 types: roughness, waviness and deviation from rights. geom. forms..

Roughness is a set of irregularities, processed surfaces with relatively small steps. The surface roughness is determined by its profile, which is formed in the cross section of this surface

Roughness and waviness are characteristics of surface quality that have a great influence on many performance properties of machine parts.

The microroughnesses under consideration are formed during the machining process by copying the shape of cutting tools, plastic deformation of the surface layer of parts under the influence of the processing tool, its friction against the part, vibrations, etc.

The surface roughness of parts has a significant impact on wear resistance, fatigue strength, tightness and other performance properties

Waviness takes intermediate position between shape deviations and surface roughness. The occurrence of waviness is associated with dynamic processes caused by the loss of stability of the machine-device-tool-part system and expressed in the occurrence of vibrations.

Surface waviness is a set of periodically repeating irregularities in which the distances between adjacent hills or depressions exceed the base length for the existing surface roughness.

Shape deviation is the deviation of the shape of the real surface or real profile from the shape of the nominal surface or nominal profile.

Accuracy is the degree to which the actual values of geometric parameters correspond to their specified (calculated) values.

Physical and mechanical properties include hardness and tension.

Residual stress occurs after machining, blanking operations, and during grinding (the material of the surface layer experiences hardening, softening, its structure and microhardness change, and residual stresses are formed). After procurement operations, the blanks obtained on the press are subjected to thermal treatment. processing.

Types of heat treatment and residual stress:

Normalization– heating the part and subsequently cooling it in air. In this case, the residual stress is removed and a hardness higher than during firing is formed. Burning– characterized by the fact that the workpiece is relieved of residual stress as a result of heating the furnace, followed by cooling inside it at the rate of cooling of the furnace. Hardening can be produced in salt solutions, in water, in oil. Residual stress is determined by calculation and experimental methods.

When experimenting. residual methods stresses are determined by calculations based on the deformation of the sample after removing the stressed layer from it. This method is destructive.

11. Precision machining. Total error. AIDS system. Types of errors.

Under processing accuracy you should understand the degree of correspondence between the actual value of the indicator and the nominal value.

The accuracy of geometric parameters is a complex concept that includes:

Dimensional accuracy of parts elements;

Accuracy of geometric shapes of surfaces of parts elements;

Accuracy of relative position of parts elements;

Roughness of surfaces of parts (microgeometry);

Waviness of surfaces (macrogeometry).

Increasing the accuracy of the initial workpieces reduces the labor intensity and mechanical processing of mechanical processing, reduces the values of allowances, and leads to metal savings.

The accuracy of the part depends on a number of factors:

Deviation from geom. shape of the part or its department. elements.

Deviation of actual part dimensions from nominal

Deviation of the surfaces and axes of parts from the exact relative position (from parallelism, perpendicularity, concentricity)

Because The accuracy of processing under industrial conditions depends on many factors; processing on machines is carried out not with achievable, but with economic accuracy.

Ec.precision mech. processing- such precision, with a cat. min s/c processing is achieved under normal operating conditions (work is carried out on serviceable machines using the necessary devices and tools with normal time consumption and normal use of workers) Achievable Accuracy– accuracy, cat. can be achieved by processing in special max. favorable conditions required for this production by highly qualified workers with a significant increase in time expenditure, not counting the processing.

AIDS: machine, device, tool, part.

The total measurement error is a combination of errors arising under the influence of a large number of factors.

Errors: theoretical, errors caused by the action of elastic force AIDS, errors caused by deformation of the workpiece under the influence of unbalanced forces, due to heat, due to wear of the cutting tool, positioning error

PRODUCTION AND TECHNOLOGICAL PROCESSES

The production process is understood as a set of individual processes carried out to obtain finished machines (products) from materials and semi-finished products.

The production process includes not only the main processes, that is, those directly related to the manufacture of parts and the assembly of machines from them, but also all auxiliary processes that make it possible to manufacture products (for example, transportation of materials and parts, inspection of parts, manufacturing of fixtures and tools , etc.).

A technological process is a sequential change in the shape, size, properties of a material and a semi-finished product in order to obtain a part or product in accordance with specified technical requirements.

The technological process of machining parts is part of the overall production process for manufacturing the entire machine.

The production process is divided into the following stages:

1) production of blank parts - casting, forging, stamping;

2) processing of blanks on metal-cutting machines to obtain parts with final sizes and shapes;

3) assembly of components and assemblies (or mechanisms), i.e. connection individual parts into assembly units and assemblies; in single production, metalworking and fitting of parts to the place of installation during assembly are used; in mass production, these works are carried out in an insignificant volume, and in mass and large-scale production they are not used, since thanks to the use of maximum calibers when processing on metal-cutting machines, interchangeability of parts is achieved;

4) final assembly of the entire machine;

5) regulation and testing of the machine;

6) painting and finishing of the machine (product). Painting consists of several operations carried out at different stages of the technological process, for example, puttying, priming and first painting of castings, painting of machined parts, final painting of the entire machine.)

At each stage of the production process, for individual operations of the technological process, control is carried out over the production of parts in accordance with the technical conditions for the part to ensure the proper quality of the finished machine (product). The technological process of machining parts must be designed and carried out in such a way that, through the most rational and economical ways processing, the requirements for parts were satisfied (processing accuracy and surface roughness, relative position of axes and surfaces, correctness of contours, etc.), ensuring correct work assembled car.

According to GOST 3.1109-73, a technological process can be design, working, single, standard, standard, temporary, prospective, route, operational, route-operational.

PRODUCTION COMPOSITION OF THE MACHINERY PLANT

Engineering factories consist of separate production units called workshops and various devices.

The composition of workshops, devices and structures of the plant is determined by the volume of product output, the nature of technological processes, requirements for product quality and others. production factors, as well as to a large extent by the degree of specialization of production and cooperation of the plant with other enterprises and related industries.

Specialization involves the concentration of a large volume of output of strictly defined types of products at each enterprise.

Cooperation involves the provision of blanks (castings, forgings, stampings), components, various instruments and devices manufactured at other specialized enterprises.

If the plant being designed will receive castings through cooperation, then it will not include foundries. For example, some machine tool factories receive castings from a specialized foundry that supplies consumers with castings centrally.

The composition of the plant’s energy and sanitary equipment may also vary depending on the possibility of cooperation with other industrial and municipal enterprises in the supply of electricity, gas, steam, compressed air, in terms of transport, water supply, sewerage, etc.

The further development of specialization and, in connection with this, widespread cooperation between enterprises will significantly affect the production structure of factories. In many cases, machine-building plants do not include foundry and forging shops, workshops for the production of fasteners, etc., since blanks, hardware and other parts are supplied by specialized factories. Many mass production factories, in cooperation with specialized factories, can also be supplied with ready-made components and assemblies (mechanisms) for the machines they produce; for example, automobile and tractor factories - finished engines, etc.

The composition of the machine-building plant can be divided into the following groups:

1. Procurement shops (iron foundries, steel foundries, non-ferrous metal foundries, forging shops, forging shops, pressing shops, forging shops, etc.);

2. Processing shops (mechanical, thermal, cold stamping, woodworking, metal coating, assembly, painting, etc.);

3. Auxiliary shops (tool shops, mechanical repair shops, electrical repair shops, model shops, experimental shops, testing shops, etc.);

4. Storage devices (for metal, tools, molding and charge materials, etc.);

5. Energy devices (power plant, combined heat and power plant, compressor and gas generator units);

6. Transport devices;

7. Sanitary installations (heating, ventilation, water supply, sewerage);

8. General plant institutions and devices (central laboratory, technological laboratory, central measurement laboratory, main office, check-out office, medical center, outpatient clinic, communication devices, canteen, etc.).

STRUCTURE OF THE TECHNOLOGICAL PROCESS

In order to ensure the most rational process of machining the workpiece, a processing plan is drawn up indicating which surfaces need to be processed, in what order and in what ways.

In this regard, the entire machining process is divided into separate components: technological operations, settings, positions, transitions, moves, techniques.

A technological operation is a part of a technological process that is performed at one workplace and covers all consistent actions a worker (or group of workers) and a machine for processing a workpiece (one or several at the same time).

For example, turning a shaft, performed sequentially, first at one end, and then after turning, i.e., rearranging the shaft in the centers, without removing it from the machine, and at the other end, is one operation.

If all the workpieces (shafts) of a given batch are turned first at one end and then at the other, then this will amount to two operations.

Installation is the part of the operation performed during one fastening of a workpiece (or several simultaneously processed) on a machine or in a fixture, or an assembled assembly unit.

So, for example, turning the shaft while fastening it in the centers is the first setting, turning the shaft after turning it and fixing it in the centers for processing the other end is the second setting. Each time the part is rotated by any angle, a new setup is created (when rotating the part, you must specify the angle of rotation).

An installed and secured installation can change its position on the machine relative to its working parts under the influence of moving or rotary devices, taking a new position.

Each position is called separate provision the workpiece occupied by it relative to the machine with its constant fastening.

For example, when processing on multi-spindle semi-automatic and automatic machines, a part, with one fastening, occupies different positions relative to the machine by rotating the table (or drum), which sequentially brings the part to different tools.

The operation is divided into transitions - technological and auxiliary.

Technological transition is a completed part of a technological operation, characterized by the constancy of the tool used, surfaces formed by processing, or the operating mode of the machine.

An auxiliary transition is a completed part of a technological operation, consisting of human and (or) equipment actions that are not accompanied by a change in shape, size and surface roughness, but are necessary to complete the technological transition. Examples of auxiliary transitions are workpiece installation, tool change, etc.

A change in only one of the listed elements (machined surface, tool or cutting mode) defines a new transition.

The transition consists of working and auxiliary moves.

A working stroke is understood as part of a technological transition, covering all actions associated with the removal of one layer of material while the tool, processing surface and operating mode of the machine remain unchanged.

On machines that process bodies of rotation, the working stroke is understood as the continuous operation of the tool, for example, on a lathe, the removal of one layer of chips by a cutter continuously, planer- removal of one layer of metal over the entire surface.

If a layer of material is not removed, but is subjected to plastic deformation (for example, during the formation of corrugations and when rolling the surface with a smooth roller in order to compact it), the concept of a working stroke is also used, as when removing chips.

An auxiliary stroke is a completed part of a technological transition, consisting of a single movement of the tool relative to the workpiece, not accompanied by a change in the shape, size, surface roughness or properties of the workpiece, but necessary to complete the working stroke.

All the actions of a worker performed during a technological operation are divided into separate techniques. Reception is understood as the completed action of the worker. Typically, techniques are auxiliary actions, for example, placing or removing a part, starting a machine, switching speed or feed, etc. The concept of “reception” is used in the technical standardization of an operation.

The machining plan also includes intermediate work - control, metalwork, etc., necessary for further processing, for example, soldering, assembly of two parts, heat treatment, etc.; final operations for other types of work performed after machining are included in the plan for the corresponding types of processing.

MANUFACTURING PROGRAM

The production program of a machine-building plant contains a range of manufactured products (indicating their types and sizes), quantities of products of each type to be produced during the year, a list and quantity of spare parts for manufactured products.

Based on the general production program of the plant, a detailed production program is drawn up for workshops, indicating the name, quantity, black and net weight (mass) of parts to be manufactured and processed in each given workshop (foundry, forging, mechanical, etc.) and undergoing processing in several workshops; a program is drawn up for each workshop and one summary one, indicating which parts and in what quantities pass through each workshop. When drawing up detailed programs for workshops to total number parts determined by the production program, spare parts are added that are supplied with manufactured machines, as well as those supplied as spare parts to ensure the uninterrupted operation of machines in operation. The number of spare parts is taken as a percentage of the number of main parts.

The production program is accompanied by drawings of general types of machines, assembly drawings and individual parts, specifications of parts, as well as a description of machine designs and technical conditions for their manufacture and delivery.

machine-building plant technological production

TYPES OF PRODUCTION AND CHARACTERISTICS OF THEIR TECHNOLOGICAL PROCESSES. ORGANIZATIONAL FORMS OF WORK

Depending on the size of the production program, the nature of the product, as well as technical and economic conditions implementation of the production process, all various productions are conventionally divided into three main types (or types): single (or individual), serial and mass. Each of these types of production and technological processes has its own characteristics, and each of them is characterized by a certain form of work organization.

It should be noted that at the same enterprise and even in the same workshop there can be different types of production, i.e. individual products or parts can be manufactured at a factory or workshop according to different technological principles: the manufacturing technology of some parts corresponds to a single production, and others - mass production, or some - mass production, others - serial production. So, for example, in heavy engineering, which has the nature of single production, small parts, required in large quantities, can be manufactured according to the principle of serial and even mass production.

Thus, it is possible to characterize the production of an entire plant or workshop as a whole only on the basis of the predominant nature of production and technological processes.

Single production is a production in which products are made in single copies, varying in design or size, and the repeatability of these products is rare or completely absent.

Unit production is universal, that is, it covers different types of products, so it must be very flexible, adapted to perform a variety of tasks. To do this, the plant must have a set of universal equipment that ensures the manufacture of products of a relatively wide range. This set of equipment must be selected in such a way that, on the one hand, it is possible to apply various types of processing, and on the other hand, so that the quantitative ratio individual species equipment guaranteed a certain throughput plant

The technological process of manufacturing parts in this type of production is compact: several operations are performed on one machine and parts of various designs and from various materials are often completely processed. Due to the varied nature of the work performed on one machine, and the inevitable consequence of this in each case of preparing and setting up a machine for a new job, the main (technological) time in the general structure of the time norm is small.

Devices for processing parts on machines are universal here, i.e. they can be used in a variety of cases (for example, a vice for fastening parts, squares, clamps, etc.). Special devices are not used or are rarely used, since the significant costs of their manufacture are not economically justified.

The cutting tool required for this type of production must also be universal (standard drills, reamers, cutters, etc.), since due to the variety of parts being processed, the use of a special tool is not economically possible.

Likewise, the measuring tool used when processing parts must be universal, i.e., measure parts of various sizes. In this case, calipers, micrometers, bore gauges, gauges, indicators and other universal measuring instruments are widely used.

The diversity of manufactured products, the uneven timing of the arrival of more or less similar designs into production, the difference in requirements for the product in terms of the accuracy of processing parts and the quality of materials used, the need, due to the variety of parts, to perform various operations on universal equipment - all this creates special conditions successful operation of workshops and the entire plant, characteristic of a single production.

These features of this type of production determine the relatively high cost of manufactured products. An increase in the demand for these products with a simultaneous reduction in their range and stabilization of product designs creates the possibility of transition from single production to serial production.

Serial production occupies an intermediate position between single and mass production.

In mass production, products are manufactured in batches or series consisting of products of the same name, similar in design and identical in size, launched into production simultaneously. The main principle of this type of production is the production of the entire batch, both in the processing of parts and in assembly.

The concept of "batch" refers to the number of parts, and the concept of "series" refers to the number of machines put into production at the same time.

In mass production, depending on the number of products in a series, their nature and labor intensity, and the frequency of repetition of series throughout the year, small-scale, medium-scale and large-scale production are distinguished. Such a division is conditional for various branches of mechanical engineering.

In mass production, the technological process is predominantly differentiated, that is, divided into separate operations that are assigned to individual machines.

Machines are used here different types: universal, specialized, special, automated, aggregate. The machine park must be specialized to such an extent that a transition from the production of one series of machines to the production of another, somewhat different from the first in terms of design, is possible.

Serial production is much more economical than individual production, since best use equipment, specialization of workers, increased labor productivity ensures a reduction in production costs.

Serial production is the most common type of production in general and medium-sized engineering.

Mass production is a production in which, with a sufficiently large number of identical outputs of products, their production is carried out by continuously performing the same constantly repeated operations at workplaces.

Mass production happens the following types:

· mass production, in which there is a continuity of movement of parts through workplaces located in the order of the sequence of technological operations assigned to certain workplaces and carried out in approximately the same period of time;

· mass direct-flow production. Here, technological operations are also performed at certain workplaces, located in the order of operations, but the time to complete individual operations is not always the same.

Mass production is possible and economically profitable when producing a sufficiently large number of products, when all the costs of organizing mass production are recouped and the cost per unit of output is less than in mass production.

The cost-effectiveness of producing a sufficiently large number of products can be expressed by the following formula

where n is the number of units of products; C is the amount of costs during the transition from serial to mass production; - cost per unit of products in mass production; - unit cost of products in mass production.

The conditions that determine the efficiency of mass production include, first of all, the volume of the production program and the specialization of the plant on certain types of products, and the most favorable condition for mass production is one type, one design of the product.

In mass and large-scale production, the technological process is built on the principle of differentiation or on the principle of concentration of operations.

According to the first principle, the technological process is differentiated into elementary operations with approximately the same execution time; Each machine performs one specific operation. In this regard, special and highly specialized machines are used here; processing devices must also be special, designed to perform only one operation. Often such a device is an integral part of the machine.

According to the second principle, the technological process involves the concentration of operations performed on multi-spindle automatic machines, semi-automatic machines, multi-cutting machines, separately on each machine or on automated machines connected in one line, performing several operations simultaneously low cost main time. Such machines are increasingly being introduced into production.

The technical organization of mass production must be very perfect. As already indicated, the technological process must be developed in detail and accurately in relation to both processing methods and calculations of main and auxiliary time.

Equipment must be precisely defined and arranged in such a way that its quantity, types, completeness and performance correspond to the specified output.

The organization of technological control is especially important in mass production, since insufficiently thorough inspection of parts and untimely rejection of unusable parts can lead to delays and disruption of the entire production process. The best results are achieved when using automatic control during processing.

Despite the small initial capital costs required to organize mass production, its technical and economic effect is correct organized enterprise is usually high and much greater than in mass production.

The cost of one and the same type of product in mass production is significantly lower, the turnover of funds is higher, transport costs are lower, and product output is greater than in mass production.

Each of the production processes described above (single, serial, mass) is characterized by corresponding forms of work organization and methods of equipment arrangement, which are determined by the nature of the product and the production process, the volume of output and a number of other factors.

There are the following main forms of work organization.

o By type of equipment, characteristic mainly of single production; used for individual parts in mass production.

Machines are located based on the homogeneity of processing, i.e., they create machine sections intended for one type of processing - turning, planing, milling, etc.

o Subject-based, characteristic mainly of mass production, is used for individual parts in mass production.

Machines are arranged in a sequence of technological operations for one or more parts that require the same processing order. The movement of parts is formed in the same sequence. Parts are machined in batches; in this case, the execution of operations on individual machines may not be coordinated with other machines. Manufactured parts are stored at the machines and then transported as a whole batch.

o Flow-serial, or variable-flow, is characteristic of serial production; machines are located in the sequence of technological operations established for the parts processed on a given machine line. Production takes place in batches, and the parts of each batch may differ slightly from each other in size or design. The production process is carried out in such a way that the operating time on one machine is coordinated with the operating time on the next machine.

o Direct-flow, characteristic of mass and, to a lesser extent, large-scale production; machines are placed in a sequence of technological operations assigned to specific machines; parts are transferred from machine to machine one by one. Transportation of parts from one workplace to another is carried out by roller tables, inclined trays, and sometimes conveyors are used, which serve here only as conveyors.

o Continuous flow, characteristic only of mass production. With this form of work organization, machines are placed in a sequence of technological process operations assigned to specific machines; the time required to perform individual operations at all workplaces is approximately the same or a multiple of the cycle.

There are several types of continuous flow work: a) with the transfer of parts (products) in simple transport devices- without traction element; b) with periodic supply of parts by a transport device with a traction element. The movement of parts from one workplace to another is carried out using mechanical conveyors that move periodically - in jerks. The conveyor moves the part through a period of time corresponding to the value of the work cycle, during which the conveyor stands and the work operation is performed; the duration of the operation is approximately equal to the value of the work cycle; c) with continuous supply of parts (products) by transport devices with a traction element; in this case, the mechanical conveyor moves continuously, moving the parts located on it from one workplace to another. The operation is performed while the conveyor is moving; in this case, the part is either removed from the conveyor to perform the operation, or remains on the conveyor, in which case the operation is performed while the part is moving along with the conveyor. The speed of the conveyor must correspond to the time required to complete the operation. The work cycle is mechanically supported by the conveyor.

For all the considered cases of working with a continuous flow, it can be established that the decisive factor determining compliance with the principle of continuous flow is not the mechanical transportation of parts, but the cycle of work.

GENERAL CHARACTERISTICS OF THE ENGINEERING COMPLEX

In Ukraine, the share of the complex's products in the total industrial output is 20%, there are such large enterprises as the Novokramatorsk Machine-Building Plant, the Kramatorsk Heavy Engineering Plant, the Kharkov Tractor Plant, the Kharkov Electrotyazhmash Plant, the Kharkov and Kiev Aviation Plants, the Transformer Plant in Zaporozhye, plant of electron microscopes in Sumy and a number of others. Medium-sized and large cities in the western regions of Ukraine became new centers of developed mechanical engineering.

The mechanical engineering complex of Ukraine is a complex, interconnected multi-industry industry that specializes in the production of machinery and equipment, devices and computer equipment, spare parts for them, technological equipment, etc. A special place belongs to the production of equipment for industrial sectors. The leading ones are chemical and petrochemical, mining and ore mining, metallurgical engineering, aviation, machine tool engineering for the light and food industries, household appliances, and agricultural machinery.

The production of metalworking equipment, especially machine tools, occupies an important place in mechanical engineering, providing it with the necessary fixed production assets. The production capabilities of mechanical engineering itself, its compliance with modern requirements and the ability to technologically re-equip the entire production and, above all, mechanical engineering, largely depend on the available fleet of machine tools, their proper technological level, and the optimal structure in terms of species composition and significance. The state and technical and technological level of machine tool industry, the structure of the country's metalworking equipment is one of the main indicators of the development of mechanical engineering and its production capabilities.

The centers of production of metalworking equipment, in particular machine tools, as well as tools, are mainly large and most reliable cities - Odessa, Kharkov, Kyiv, Zhitomir, Kramatorsk, Lvov, Berdichev; production of forging and pressing machines is located in Odessa, Khmelnitsk, Dnepropetrovsk, Strie; industry for the production of artificial diamonds and abrasive materials - in Poltava, Lvov, Zaporozhye, Kyiv; production of metalworking and woodworking tools - in Zaporozhye, Khmelnitsk, Vinnitsa, Kharkov, Kamyanets-Podolsky, Lugansk. The centers of aircraft manufacturing are Kyiv and Kharkov.

A machine is a mechanical device with coordinated parts that carry out specific and appropriate movements to transform energy, materials or information.

The main purpose of the machine is to replace production functions people to make work easier and increase productivity.

Machines are divided into energy machines (i.e., those that convert energy from one type to another) - electric motors, electric generators, engines internal combustion, turbines (steam, gas, water, etc.).

Working machines - machine tools, construction, textile, computing machines, automatic machines.

Mechanical engineering is a branch for the production of machines. Mechanical science is the science of machines (TMM, metal science, resistance, materials, machine parts, etc.).

Any machine consists of individual components and parts. At the same time, a significant part of the parts is standardized and common to many types of machines - bolts, screws, axles, scales, etc. They can be produced at separate specialized mass production enterprises, which makes it possible to fully automate and mechanize the entire technical line their manufacture.

From individual parts, units are also sometimes produced for mass general purpose - gearboxes, pumps, brakes, etc. Larger connections of parts and assemblies can be considered as units or assemblies.

For example, engines are components of automobiles, combine harvesters, and airplanes and are also manufactured in separate factories.

That is, all machine-building enterprises are very closely related to each other by technical and economic indicators. The work of each machine-building enterprise largely depends on suppliers of metal products, parts, and assemblies.

In addition to internal industry connections, mechanical engineering is connected with other industries that supply mechanical engineering with polymers, rubber, fabrics, wood, etc., which are used in mechanical engineering as structural and additional materials.

Coursework: Technological process of machining parts

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Chemical composition of steel (GOST 1050-88) in table 2:

table 2

Mechanical properties of steel 30 GOST 1050-88 in table 3:

Table 3

Part manufacturing route

1. Drilling (machine 2N135):

a) Drill hole 35

b) countersink 38.85

c) (machine T15K6) - reamer 40

(Normalized 3 jaw chuck)

2. Locksmith

3. (machine brand 16K20F3) CNC lathe

a) cut the end to size 163 (-0.3)

b) sharpen the sphere R150

(Spreading mandrel (collet))

4. (machine brand 16K20F3) CNC lathe

a) trim the end maintaining size 161 (-0.3)

b) sharpen the sphere R292

(Spreading mandrel)

5. Horizontal milling machine brand 6M82G with an 8 mm end mill, 10.5 mm deep. (Special device)

6. Locksmith.

7. Cementation.

8.Hardening

9.Vacation

10.Cleaning and hardness control

11.Cleaning (heat treatment and calibration)

12. (machine brand 2N135) reamer 40.

13. (machine brand 3E710A) surface grinding. Reset the grinding to size 160.

14. Washing.

15. Test.

Machine models

2N118

2N125

2N135

Largest nominal drilling diameter.mm

18

25

35

Vertical movement of the drilling head, mm

150

200

250

Number of spindle speed steps

9

12

12

Spindle rotation speed rpm

180-2800

45-2000

31,5-1400

Number of feed feet

6

9

9

Spindle feed.rpm

0,1-0,56

0,1-1,6

0,1-1,6

Torque on the spindle, N

88

250

400

Maximum permissible feed force, N

5,6

9

15

Electric motor power, kW

1,5

2.2

4

Machine efficiency

0,85

0,8

0,8

From the tables we select the following machines: 2N135 16K20F3 6M82G 3E10A

6 . Choicetool

Bibliography