Receiving blanks

To produce parts (blanks), it is necessary to have blanks from which, ultimately, finished parts are obtained. Currently, the average labor intensity of procurement work in ship engineering is 40...45% of the total labor intensity of machine production. The main trend in the development of blank production is to reduce the labor intensity of machining in the manufacture of machine parts by increasing the accuracy of their shape and size.

A workpiece is an object of labor from which a part is made by changing its shape, size, surface properties and (or) material.

There are three main types of blanks: machine-building profiles, piece and combined blanks.

The workpieces are characterized by their configuration and dimensions, the accuracy of the obtained dimensions, surface condition, etc.

Main types of blanks:

Varietal material;

Castings;

Forgings and stampings

Sectional material (rolled material) can have the following profiles:

Round, square and hexagonal bars,

Pipes, sheets, strips, tapes.

Angle, channel, I-beam,

Special profile at customer's request.

Blanks can also be made from non-metallic materials: vinyl plastic, getinax, textolite, etc.

Heat treatment of metals is the process of processing products made of metals and alloys by thermal action in order to change their structure and properties in a given direction.

Heat treatment of metals is divided into:

Actually thermal, consisting only of thermal effects on the metal,

Chemical-thermal, combining thermal and chemical effects,

Thermomechanical, combining thermal effect and plastic deformation.

Shaping, pressure processing.

Pressure processing of metals is based on the ability of metals and a number of non-metallic materials, under certain conditions, to obtain plastic, residual deformations as a result of the influence of external forces on the deformed body (workpiece).

One of the significant advantages of metal forming is the possibility of significantly reducing metal waste compared to cutting.

Another advantage is the possibility of increasing labor productivity, because As a result of a single application of force, the shape and dimensions of the workpiece can be significantly changed. In addition, plastic deformation is accompanied by a change in the physical and mechanical properties of the workpiece metal, which can be used to obtain parts with the required service properties (strength, rigidity, wear resistance, etc.) with the smallest weight.

Forging is a type of hot metal forming in which the metal is deformed under the influence of blows from a universal tool - a hammer. The metal flows freely to the sides, not limited by the working surfaces of the tool. Forging produces blanks for subsequent machining. These blanks are called forged forgings or simply forgings. Forging is divided into manual and machine. The latter is produced using hammers and hydraulic presses. Forging is the only possible way to produce heavy workpieces, especially in single production. As a rule, every instrument-making plant has at least one hammer or hydraulic press.

Pressing involves pressing a workpiece in a closed form through the hole in the matrix. The shape and cross-sectional dimensions of the extruded part of the workpiece correspond to the shape and dimensions of the die hole, and its length is proportional to the ratio of the cross-sectional areas of the original workpiece and the extruded part and the movement of the pressing tool. By pressing, rods with a diameter of 3 - 250 mm, pipes with a diameter of 20 - 400 mm with walls 1.5-12 mm thick and other profiles are made. By pressing, profiles are also produced from structural, stainless and special steels and alloys. The accuracy of extruded profiles is higher than that of rolled ones. The disadvantages of pressing include large waste of metal, because All metal cannot be squeezed out of the container. The weight of the press residue can reach 40% of the weight of the original workpiece.

Stamping is the process of changing the shape and size of a workpiece using a specialized stamp tool. Each part has its own stamp. There are cold forging and hot die forging.

There are:

Cold stamping

· Hot die forging

Vibration rolling is the process of processing the surfaces of a part by rolling them with balls or rollers made of carbide material under a certain pressure and with oscillations along the line of movement. In this way, a significant improvement in surface quality is achieved, i.e. increased accuracy, reduced roughness and improved physical properties material. Using this process, it is possible to create surfaces with the required microrelief. In addition, this process is also used for decorative purposes.

A foundry is a production that produces shaped parts or blanks by pouring molten metal into a cavity mold that has the configuration of the part.

Casting in sand-earth molds.

Casting in sand-earth molds is one of the oldest casting methods. Using this casting method, large-sized parts from ferrous and non-ferrous alloys with a complex configuration are produced in a single production. The diagram for obtaining a casting is shown in the figure.

Injection molding.

Die casting is the most productive method for producing thin-walled parts with complex shapes from zinc, aluminum, magnesium and copper alloys.

Lost wax casting.

Lost wax casting is widely used for the production of castings of complex configuration weighing from a few grams to 10-15 kg, with a wall thickness of 0.3-20 mm or more, with dimensional accuracy up to the 9th grade with a surface roughness from 80 to 1.25 microns .

Machining

Metal cutting is a processing that involves the formation of new surfaces by separating surface layers material with the formation of chips.

A reamer is a multi-toothed tool that, like a drill and a countersink, during processing rotates around its axis (the main movement) and moves forward along the axis, making a feed movement.

Countersinks differ from drills in the design of the cutting part and a large number cutting edges.

Countersinking - provides the necessary accuracy and cleanliness of holes produced by casting, forging or stamping. Countersinking is mostly an intermediate operation between drilling and reaming, so the diameter of the countersink must be less than the final size of the hole by the amount of allowance removed by the reamer.

Countersinking. It is produced by countersinks, which have cutting edges at the end of the tool (Fig. 139). By design, countersinks are cylindrical, conical and flat.

Cylindrical countersinks (Fig. 139, a) are used for processing sockets with a flat bottom for the heads of bolts and screws. To ensure alignment, the countersinks have a guide pin.

Conical countersinks (Fig. 139, b) have a sharpening angle of the conical part equal to 60; 70; 90 or 120°.

Countering is the processing of the surface of a part around a hole (a type of countersinking designed to form planes or recesses for a screw head, washer, thrust ring, etc. Counterings are made in the form of mounted heads having four teeth at the end. Counterings process bosses for washers, thrust rings , nuts. Countering is carried out on drilling, boring and other metal-cutting machines by counterbore.

A cutter is a metal-cutting tool for cutting teeth of spur and helical gears of external and internal gearing, toothed rims of chevron wheels with and without a groove, gear wheels of blocks, gear wheels with protruding flanges that limit the free exit of the tool and gear racks.

Shever is a gear-cutting tool used for shewing. Shaving - (from the English shaving - shave) - finishing treatment of the side surfaces of gear wheels. Shewing involves removing thin chips with a shaver. The shaver is a wheel or rack, the teeth of which are cut with transverse grooves to form cutting edges.

The cutting process is divided into: turning, milling, drilling,

planing, chiselling, broaching, broaching, grinding and finishing processing methods.

Turning, in turn, is divided into: turning, boring, trimming, cutting.

Drilling: reaming, countersinking, countersinking, reaming, counterbore.

Finishing methods:

polishing, finishing, lapping, honing, superfinishing, diamond turning and grinding, shaving. Only the most widely used types of processing are listed.

The technological process of assembly is a set of operations for connecting, coordinating, fixing, securing parts and assembly units (AU) to ensure their relative position and movement required functional purpose assembly unit and general assembly of the product.

A subassembly is a frill whose object is a component part of the product.

A general assembly is an assembly whose object is the product as a whole. Components are products of the supplier company, used as an integral part of the product manufactured by the company. Assembly kit is a group components products that need to be brought to the workplace to assemble the product or its component.

The following types of products are installed: parts, assembly units, complexes and kits.

A part is a product made from something that is homogeneous in name and

grade of material, without the use of assembly operations. Parts also include coated products

An assembly unit is a product whose components are to be connected to each other at the manufacturer (by screwing, riveting, welding, etc.). This concept is adequate to the concept of “node”, less often “group”, but can also be a finished product. It should be taken into account that the technological concept of “assembly unit” is broader than design terms, because can be divided into several units when developing a technological process.

Complex; two or more specified items not joined together

manufacturing plant assembly operations, but intended to perform interrelated operational functions (for example, a program-controlled machine, a computer, etc.).

Set: two or more products not connected together

manufacturer by assembly operations and representing a set of products that have a general operational purpose of an auxiliary nature (a set of spare parts, tools and accessories, etc.).

Assembly process operation is a completed part

technological process performed at one workplace.

Classification of types of connections.

1. According to the integrity of connections: detachable and permanent connection.

2. According to the mobility of the components: movable and fixed connection.

3. According to the shape of the contacting surfaces: flat, cylindrical,

conical, etc.

4. According to the method of forming connections: threaded, keyed, pin,

press, etc.

Classification of types of assembly.

By assembly object: node and general.

By assembly sequence: serial, parallel,

series - parallel.

By stages of assembly: preliminary, intermediate, final.

According to the mobility of the assembly object:

1. movable with continuous movement,

2. movable with periodic movement,

3. motionless (stationary).

On production organization:

1. Typical, continuous with the use of vehicles.

2. Typical, continuous without the use of vehicles.

3. Group, continuous with the use of vehicles.

4. Group, continuous without the use of vehicles.

5. Group, not continuous.

6. Single.

On mechanization and automation:

1. automatic,

2. automated,

3. mechanized,

4. manual.

According to the method of ensuring assembly accuracy:

1. fully interchangeable,

2. selective assembly,

3. with incomplete interchangeability,

4. with fit,

5. with compensation mechanisms,

6. with compensation materials.

Typical assembly process.

1. Picking operation. The kit part is selected according to the specification.

2. Depreservation.

3. Assembly. For each product and depending on the type of production

its own route and operating technology.

4. Setting, adjustment, testing.

5. Test.

6. Packaging.

Testing of ship mechanisms, equipment, and devices includes:

Bench displays of individual mechanisms and equipment at the manufacturing plant;

Mooring, running gear during ship construction.

Common goal testing is to check the compliance of indicators with design data. At the same time, it is also important to check the quality and reliability of the mechanisms and equipment installed on the ship. Each stage of testing provides for checking the readiness of the equipment for testing at the next stage.

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 basic, i.e., those directly related to the manufacture of parts and the assembly of machines from them, processes, but also all auxiliary processes, providing the ability to manufacture products (for example, transporting materials and parts, checking parts, manufacturing 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.

Process Machining of parts is part of the overall production process of 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., the connection of 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 performed 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 the entire machine;

5) regulation and testing of the machine;

6) painting and finishing of the machine (product). Painting consists of several operations performed on different stages 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, long-term, 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 strictly certain types 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.

Composition of energy and sanitary technical devices The plant can also be different 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 performed at one workplace and covering all sequential actions of a worker (or group of workers) and a machine for processing a workpiece (one or more simultaneously).

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 rotating devices, taking a new position.

Position is each individual position of the workpiece that it occupies relative to the machine while being fixed unchanged.

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.

If a layer of material is not removed, but is exposed plastic deformation(for example, when forming corrugations and when rolling a surface with a smooth roller in order to compact it), and also use the concept of a working stroke, 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 the 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.

PRODUCTION PROGRAM

The production program of a machine-building plant contains a range of manufactured products (indicating their types and sizes), quantities of each type of product 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, forge, 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, the total number of parts determined by the production program is supplemented with spare parts supplied with manufactured machines, as well as those supplied as spare parts for supply. uninterrupted operation 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 descriptions of machine designs and technical specifications for their production 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 the technical and economic conditions 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 characteristic features, 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 various types 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 single production, and others to mass production, or some to mass production, others to serial production. So, for example, in heavy engineering, which has the nature of single production, small parts that are 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 manufactured 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 of individual types of equipment guarantees a certain throughput of the 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 diversity of work performed on one machine, and the inevitable consequence of this, in each case, preparing and setting up a machine for a new job, the main (technological) time in general structure time norms are 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 processed parts, the use special tool economically not 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 for successful work workshops and the entire plant, characteristic of a single production.

These features of this type of production determine relatively high cost 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 is of the following types:

· flow-mass production, in which there is a continuous 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 enough large quantity 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 with little time spent. 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. Best results are achieved using automatic control during processing.

Despite the small initial capital costs required to organize mass production, its technical and economic effect in a properly organized enterprise is usually high and significantly 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) by simple transport devices - without a 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. The new centers of developed mechanical engineering have become medium-sized and big cities western regions of Ukraine.

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 the mechanical engineering industry itself and its compliance largely depend on the available fleet of machine tools, their proper technological level, and the optimal structure in terms of species composition and significance. modern requirements and the ability to technologically re-equip all production and, above all, mechanical engineering. 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 human production functions to facilitate labor and increase productivity.

Machines are divided into energy machines (i.e. those that convert energy from one type to another) - electric motors, electric generators, internal combustion engines, 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 of their production.

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.

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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 of the 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. Preparation of technical documentation

Literature

Introduction

Modern mechanical engineering is very high demands to 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 the workpiece by removing allowance with cutting tools on metal-cutting machines, ensuring the specified accuracy and roughness of the machined surface.

Depending on the shape of the parts, the nature of the surfaces being processed and the requirements placed on them, their processing can be carried out in various ways: mechanical - turning, planing, milling, drawing, grinding, etc.; electrical - electric spark, electric pulse or anodic-mechanical, as well as ultrasonic, electrochemical, radiation and other processing methods.

The process of metal cutting plays a leading role in mechanical engineering, since the accuracy of shapes and sizes and high frequency In most cases, the surfaces of metal machine parts can be achieved only by such treatment.

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 individual species cutting operations related to metalwork are performed manually or using mechanized tools.

IN modern methods In the mechanical processing of metals, the following trends are noticeable:

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 ones;

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 precision casting and forming methods and 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

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 parts large sizes- 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 engaged in the production of 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 process of crystallization of molten metal, the mechanical and operational properties of castings are formed.

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;

4. The size of the production program, characterizing the type of production of a given part.

In single small-scale production, universal machines are used; in serial production, along with universal machines, semi-automatic machines and automatic machines are widely used; in large-scale and mass production - special machines, automatic machines, aggregate 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

Indicator	Machine models

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

Spindle speed, rpm
Number of caliper feed stages
Caliper feed. 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

Indicator	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

Indicator	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 processed surfaces, the workpiece material and its mechanical properties.

The tool must ensure the required accuracy of shape and size, the required roughness of machined surfaces, high productivity and durability, and 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 has vital importance in achieving high processing 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 outer 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 the 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 values of the 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, re-adjustable, 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 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. Registrationtechnicaldocumentation

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 calculated 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. Persons who have passed a medical examination, completed introductory briefing, initial briefing at the workplace, and have a labor protection certificate are allowed to work independently.

2. Perform only work within the scope of duties.

3. Work only in serviceable, neatly tucked work clothes 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 equipment unattended.

When leaving even for 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 onto parts or 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;

possibility of burns and mechanical damage shavings;

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 shortcomings 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, it is prohibited to 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, 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.

References

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: ( 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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Process structure

TECHNOLOGICAL PROCESS AND ITS STRUCTURE (BASIC CONCEPTS AND DEFINITIONS)

Production and technological processes

Factory production process(site, workshop) refers to the entire complex of processes of organization, planning, supply, manufacturing, control, accounting, etc., necessary for converting materials and semi-finished products arriving at the plant into finished products of the plant (shop). Thus, production process- this is the totality of all actions of people and production tools carried out for the manufacture of manufactured products at a given enterprise.

The production process is complex and diverse. It includes: processing of blanks to obtain parts from them; assembly of components and engines and their testing; movement at all stages of production; organization of maintenance of workplaces and sites; management of all levels of production, as well as all work on technical preparation of production.

Of course, in any production process, the most important place is occupied by processes directly related to achieving the specified product parameters. Such processes are called technological. Process- this is a part of the production process that contains actions to consistently change the size, shape or condition of the object of labor and their control (GOST 3.1109-82).

In the production of aircraft engines, a variety of processes are used: casting, pressure and cutting processing, thermal and physical-chemical treatment, welding, soldering, assembly, testing. Thus, according to the type of process and type of product, the technological process of casting, for example, turbine blades, is distinguished; technological process of heat treatment, for example, of a turbine shaft; technological process of mechanical processing, etc. In relation to shaping processes, it can be formulated that a technological process is a system of mutually agreed upon operations involving the sequential transformation of a semi-finished product into a product (part, workpiece...) by shaping using mechanical, physical-mechanical, electrophysical-chemical and other methods.

Process structure

The main element of the technological process is the operation .

Operation- this is a part of the technological process performed at one workplace by one or more workers, one or more pieces of equipment before moving on to processing the blank of the next part.

For an operation to exist, at least one of the two specified conditions is sufficient. If, for example, the process consists of grinding a workpiece on a grinding machine and electric spark alloying of this surface on another, then regardless of the number of parts (at least one part), there will be two operations in the technological process, since the workplace changes (Fig. 2.1).

Rice. 2.1. Process operations (fragment)

However, processing at one workplace can also consist of several operations. If, for example, drilling and reaming of parts is carried out on one drilling machine, in such a way that first the entire batch of parts is drilled, and then, according to circumstances, the equipment is readjusted (replacement of tools, fixtures, processing modes, lubricant-cooled environment, measuring instruments, etc. .), carry out deployment, then you get two operations - “drilling”, the second “deployment”, although there is only one workplace.

Workplace- this is part of the area (volume) of the workshop intended for performing an operation by one or a group of workers, in which technological equipment, tools, devices, etc. are located.

The concept of “operation” refers not only to the technological process (TP), which involves shaping. There are control, testing, washing, strengthening, thermal, etc. operations.

The operation is characterized by:

The immutability of the processing object;

Invariance of equipment (workplace);

Consistency of working performers;

Continuity of execution.

Technological process design consists of establishing:

Composition (nomenclature) of operations;

Sequences of operations in TP;

An operation is an indivisible part of the technical process from a planning and organizational point of view. It is the basic unit of production planning. The entire production process is based on a set of operations:

Labor intensity;

Logistics (machines, tools, etc.);

Qualification and number of workers;

Required production space;

The amount of electricity, etc. is determined by operation.

The operation is carefully documented.

The operation may consist of several transitions. A transition is a part of an operation during which the same surface of a part is processed, using the same tool, with the same operating mode of the machine.

Rice. 2.2. Technological transitions

A– two simple transitions (Ι and ΙΙ); b– one complex (explanations in the text)

In Fig. Figure 2.2 shows the operation of stitching holes using the electrochemical method. As can be seen from Fig. 2.2, A holes are sequentially obtained when implementing transitions Ι and ΙΙ. To improve performance, several are often combined simple transitions into one complex transition (Fig. 2.2, b); this allows you to process multiple surfaces at the same time.

A technological transition may contain several passages. The pass is the part of the transition during which one layer of metal is removed (applied). Dividing into passes is necessary in cases where it is not possible to remove (apply) the entire metal layer in one step (due to the strength of the tool, the rigidity of the machine, accuracy requirements, etc.).

The operation can be performed in one or more workpiece setups. Installation represents part of a technological operation performed during one workpiece fixation.

In many cases, operations are divided into positions. Position- a fixed position occupied by a permanently fixed workpiece together with a device, relative to a tool or a stationary piece of equipment to perform a certain part of the operation. Thus, a position is each of the various positions of the workpiece relative to the tool or the tool relative to the workpiece when it is held in one position, such as milling each of the four faces of a screw head when it is held in a single fixture.

The difference between position and setting is that in each new setting the new relative position of the workpiece and the tool is achieved by re-fixing the workpiece, and in each new position - without unfastening the workpiece, by moving or rotating the workpiece or tool to a new position. Replacing settings with positions always reduces processing time, since turning a fixture with a workpiece or a head with a tool takes less time than unfastening, reinstalling and securing the workpiece.

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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

References

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.