Technological process in mechanical engineering. Technological process Technological processes of mechanical engineering production

The manufacture of products at machine-building enterprises is carried out as a result of the production process.

Manufacturing process - This is the totality of all the actions of people and production tools necessary at a given enterprise for the manufacture or repair of manufactured products. The production process in mechanical engineering covers the preparation of means of production and the organization of maintenance of workplaces; receipt and storage of materials and semi-finished products; all stages of manufacturing machine parts; assembly of products; transportation of materials, blanks, parts, finished products and their elements; technical control at all stages of production; packaging of finished products and other actions related to the manufacture of manufactured products.

The most important stage of the production process is technologiststechnical preparation of production(TPP), the main element of which is the technological process (TP).

Technological process - This is a part of the production process that contains targeted actions to change and/or determine the state of the subject of labor (workpiece or product). There are technological processes for the manufacture of initial workpieces, heat treatment, mechanical (and other) processing of workpieces, and assembly of products.

In the process of manufacturing blanks, the material is converted into initial blanks of machine parts of given sizes and configurations using various methods. During heat treatment, structural transformations of the workpiece material occur, changing its properties. During machining, there is a consistent change in the state of the original workpiece (its geometric shapes, sizes and number of surfaces) until the finished part is obtained. TP of an assembly is associated with the formation of detachable and permanent connections of component parts of products.

To implement any technological process, it is necessary to use a set of production tools called means of technological equipmentnia(STO) is technological equipment(casting machines, presses, metal cutting machines, furnaces, test benches, etc.) and thosenological equipment(cutting tools, fixtures, dies, measuring instruments, etc.).

TP is performed at workplaces. Workplace - a section of the production area equipped in accordance with the work performed by us.

Technological operation called a completed part of the technical process performed at one workplace. The operation covers all actions of the workshop and workers on one or more jointly processed or assembled production objects. When processing on machines, the operation includes all the actions of the worker, as well as automatic actions of the machine until the workpiece is removed from the machine and proceeds to processing another workpiece.

In addition to technological ones, there are also auxiliary operations: transportation, control, labeling, etc.

When performing technological processes at an enterprise, a workpiece or assembly unit sequentially passes through workshops and production areas in accordance with the operations performed. The specified sequence is called technological route, which can be intra-shop and inter-shop.

Technological transition – a completed part of a technological operation, performed by the same workshops under constant technological conditions (t, s, P and etc.). Technological transitions can be simple (processing with one tool) or complex (several tools are involved in the work simultaneously).

When processing workpieces on CNC machines, several surfaces can be sequentially processed with one tool. In this case, they say that the specified set of surfaces is processed as a result of executing instrumental transition.

Auxiliary transition – This is a completed part of a technological operation, consisting of human and/or equipment actions that are not accompanied by a change in the properties of objects of labor, but are necessary to complete a technological transition (installation and securing of a workpiece, changing tools, changing processing modes, etc.).

Working stroke – a completed part of a technological transition, consisting of a single movement of the tool relative to the workpiece, accompanied by a change in the shape, size, surface quality or properties of the workpiece.

Installation – part of a technological operation performed with constant fastening of the workpiece or assembly unit being processed.

Position – a fixed position occupied by a permanently fixed workpiece or assembled assembly unit together with a device relative to a tool or fixed parts of equipment to perform a certain part of the operation. Changing positions performed using rotary devices and linear movement devices is possible, for example, in technological operations carried out on turret-type equipment, aggregate machines, automatic lines, etc.

Working method – manual action of a worker servicing a machine or unit that ensures the implementation of a technological transition or part of it. Thus, when performing an auxiliary transition of installing a workpiece into a fixture, it is necessary to sequentially perform the following techniques: take the workpiece from the container, install it in the fixture and secure it in it.

Manufacturing of mechanical engineering products can be carried out on the basis single, typical or group TP. A single TP is designed and used for the manufacture of parts of the same name, standard size and design, regardless of the type of production.

A typical technological process is characterized by the unity of content and sequence of most technological operations and transitions for a group of products with common design features. A typical TP is used either as an information basis for the development of a working TP, or as a working TP if all the necessary information for the manufacture of a part is available.

Group TP is used for joint production or repair of a group of products of various configurations under specific production conditions at specialized workplaces. The fundamental difference between standard and group processes is as follows: standard technology is characterized by the commonality of the technological route, and group technology is characterized by the commonality of equipment and fixtures necessary to perform a certain operation or complete production of a part.

According to the degree of detail, TPs are divided into route, operational And route and operational.

In a route TP, the content of operations is stated without indicating transitions and processing modes.

Operational TP is a technological process performed according to documentation in which the content of operations is outlined, indicating transitions and processing modes.

Route-operational TP is a technological process carried out according to documentation in which the content of individual operations is outlined without indicating transitions and processing modes.

The analysis of existing and design of new technological processes must be carried out taking into account the type of production organization in which they are carried out. There are three main types of engineering production: mass, serial And single. In some cases, mass production is divided into large-scale, medium-scale And small-scale. The main factors that determine the type of organization of production in a workshop or on a site are the range of products, the production program and the labor intensity of manufacturing parts.

The type of operating production is determined fixed coefficientleniya operations

Where ABOUT – the number of different operations in one month;

R – the number of workplaces at which various operations are performed.

For mass production
. For high volume production
, for mid-production
, for small-scale
. For single production
not regulated.

When designing product manufacturing processes, serial production is determined by serialization coefficient

, (1.2)

Where – product release cycle;

– average piece time for operations.

Release stroke – the time interval through which products of a certain name, standard size and design are periodically produced is calculated using the formula

, (1.3)

Where – actual annual operating time of equipment for one shift in hours;

T – number of equipment shifts per day;

N – annual product production program, pcs.

To find t sh.sr . it is necessary either to carry out standardization according to enlarged standards, or to use data on the labor intensity of a similar part existing in production.

Average piece time is calculated using the formula

, (1.4)

Where t w. i – piece time i- part manufacturing operations;

P – number of main operations on the route.

By value TO With , calculated using formula (1.2), a decision can be made on the type of production. At TO With ≤ 1 – mass production, 1< TO With ≤ 10 – large-scale, 10< TO With ≤ 20 – average series, 20< TO With ≤ 50 – small-scale, TO With > 50 – single production.

Serial production has a significant impact on the technological preparation of product release.

In mechanical engineering, two working methods are used: flow and non-flow. Flow production is characterized by the location of service stations in the sequence of TP operations and a certain interval for the production of products (release stroke). In the general case, the condition for organizing a flow is the multiplicity of the execution time of each operation to the release cycle, i.e. t w. i / τ V = TO (TO = 1,2,3,...). Bringing the duration of operations to a specified condition is called synchronization.

Labor productivity corresponding to a dedicated production site (line, workshop) is determined by the rhythm of production. Rhythmrelease– the number of products of a certain name, standard size and design, produced per unit of time. Ensuring a given rhythm of product release using the flow method of work in mass and large-scale production is the most important task in the design of technological processes.

Organizing production using the flow method ensures an increase in labor productivity, a reduction in the production cycle and the volume of work in progress, provides for the use of high-performance equipment and comprehensive automation of the manufacture of parts, including heat treatment, coating, washing, control, etc.

In mass production, workpieces are moved between work stations in batches. Party name the number of blanks or parts of the same name and standard size that are put into production or submitted for assembly.

The optimal batch size is calculated using the formula

n = N K/F , (1.5)

Where N – annual program with spare parts, pcs.;

TO – the number of days for which it is necessary to have a supply of parts in stock (2...10 days);

F – number of working days in a year.

The machine, which has completed processing a batch of workpieces, is readjusted for another operation. The size of a batch of parts depends on the product range, the annual program, the order period, the duration of processing and assembly, complexity, availability of materials and other factors. Taking these factors into account, the calculated batch size may be different.

In mass production, to increase equipment load, they use variable-flow (serial-flow) And group lines. In variable-flow processing, each machine of the line is assigned to perform several operations for technologically and structurally similar parts, which are processed alternately. Variable flow line devices are designed so that the entire fixed group of workpieces can be installed in them.

In group production lines, each machine performs operations along different technological routes. When moving on to processing the next parts, the machine is adjusted (change of collet, clamp, drill, etc.), which makes it possible to process similar surfaces of a group of workpieces.

The possibility of using the flow method of work is determined coflow factorTO P – comparison of average piece time t sh.sr. for basic operations with the release cycle of parts τ V :

. (1.6)

At flow rate TO P > 0.6 adopt the continuous work method.

The non-flow production method is characterized by the production of parts in batches at each operation; processing equipment is installed in the workshop in groups according to machine types (lathes, milling, grinding, etc.); products are assembled on stationary devices. The non-line production method requires the creation of reserves, which lengthens the production cycle.

Production cycle – This is the period of time from the beginning to the end of any repetitive technological or production process. Shortening the production cycle reduces interoperational backlogs, work in progress and working capital, and the turnover of funds invested in production increases significantly.

The concept of "batch" refers to the number of machines that are put into production simultaneously or continuously over a certain period of time.

An important principle for developing a technological route for the passage of parts through the workshops of a plant is the principle of reducing the technological route as much as possible with the shortest mileage of parts between workshops.

The connection diagram of the workshops of a medium-sized plant is shown in Fig. 1.1.

As can be seen from the diagram (Fig. 1.1), on the way to the assembly shop, workpieces and parts can make double runs between shops. When designing the sequence of processing of individual parts within a workshop, care should be taken to minimize the mileage of parts between operations.

The structure of mechanical assembly production depends on the design and technological features of products, type of production and a number of other factors. Products produced by factories are distributed among workshops according to subject, technological or mixed sign.

When organizing workshops according to subject matter, each of them is assigned all the parts of a particular unit or product and their assembly. In this case, all workshops are mechanical assembly shops and include mechanical and assembly departments (areas). If there are several mechanical assembly shops that manufacture individual components, the plant provides a general assembly shop for the manufactured machines. This organization of workshops is typical, as a rule, for mass and large-scale types of production.

P When organizing workshops according to technological characteristics, parts of different machines and assemblies are grouped according to similar technical specifications. This form of organization is typical for single and serial types of production, since here it is usually not possible to fully load the equipment with parts of one product. Shops process similar parts, regardless of which unit or machine they belong to. In this case, machining production is divided into workshops according to the type of parts and the homogeneity of the process (for example, workshops for body parts, shafts, gears, hardware, etc.). The assembly shop is divided into an independent workshop, which receives parts from various workshops.

The organization of workshops according to mixed characteristics is usually found in mass production with a large range of products. In this case, for the manufacture of some products, workshops are organized on a subject basis (for example, workshops for gearboxes, electric motors, vacuum cleaners, etc.), and for the rest of the products - on a technological basis.

The production of standard parts is usually allocated to separate workshops, regardless of the adopted production organization scheme.

Unification and standardization of mechanical engineering products contributes to the specialization of production, narrowing the range of products and increasing their output, and this in turn allows for the wider use of flow methods and production automation.

Introduction
1.Machine as an object of production
2 Production process and its structure
3 Technological process and its structure
4 Types of production and their characteristics
Conclusion
List of sources used

Introduction

The production process is based on the technological process. It includes all processing operations directly related to changing the shape, size and properties of the manufactured product, performed in a certain sequence. There are such technological processes: pressure treatment, mechanical processing, heat treatment, assembly and many others. At the plant, technological processes and technological documentation are developed by the department of the chief technologist. Properly developed technological processes ensure that all operations for the manufacture of industrial products are performed with minimal costs of materials, labor and energy.

Types of production. This type of production is characterized by the use of universal equipment, which processes parts of various shapes and sizes, universal devices and measuring tools, a significant amount of manual work, and the use of highly qualified workers. The cost of parts in such factories is much higher than in factories with a different type of production, and labor productivity is much lower. Typical representatives of this type of production are heavy engineering plants, turbine plants, shipbuilding plants, chemical engineering plants, etc. In addition, modern machine-building plants with mass and serial production have experimental workshops where new models of machines are created in one or several copies, which is typical for individual production.

Serial production is characterized by the release of certain batches (series) of identical products, which are repeated at certain intervals, and the use of high-performance special equipment, fixtures, fixtures and tools. Depending on the size of the batch (series) of manufactured products, three types of mass production are distinguished: large-scale, which in its nature is close to mass production, medium-scale and small-scale. Typical representatives of mass production plants are diesel locomotive, machine tool, etc. Mass production is characterized by the production of a large number of identical products (machines) over a long period of time, narrow specialization of jobs, and the use of high-performance special equipment (automatic lines, automatic and semi-automatic machines, modular machines) , as well as special equipment, fixtures and tools, wide interchangeability of parts.

Factories of this type include automobile and tractor manufacturing, piston factories, etc. Principles of continuous production. In mechanical engineering, there are two forms of production organization: flow and non-flow. A characteristic feature of flow production is the assignment of certain operations to workplaces, the location of workplaces in the technological sequence of processing operations. At the same time, the time for transferring a part from one workplace to another is reduced to a minimum. The flow form of production organization is characteristic of serial and mass production plants. If operations are not assigned to workstations and equipment is installed regardless of the technological sequence of processing, then these are characteristic features of non-line production.

Process elements

Every technological process consists of individual elements. Such elements are: operation, installation, position, transition, passage, working technique. A technological operation is understood as a part of the technological process of processing a workpiece, performed at one workplace (machine) with one tool (cutter, file, etc.) by one or more workers. Depending on the amount of work being performed, operations can be simple or complex. A complex operation can be broken down into individual components called setups.

Thus, installation is part of the operation that is performed on the machine (workplace) with the workpiece being fixed unchanged. A position is a part of an operation that is performed with one constant position of the workpiece relative to the tool (not counting the movements associated with the working movements of the workpiece or tool). The part of the operation for processing one or simultaneously several surfaces of a workpiece, which is performed with the machine mode and tool (or several tools) unchanged, is called a transition. A pass is the part of the transition in which one layer of metal or other material is removed. A working technique is the completed action of a worker when performing an operation (fastening or removing a workpiece, cutting tool, etc.).

Multi-position processing. High labor productivity in machine-building plants during machining is achieved through the widespread introduction of progressive technological processes and the use of special high-performance equipment, fixtures and tools. Depending on the type of production and available equipment, the processing of parts can be performed in two different methods: on a small number of different machines and on a relatively large number of machines, each of which performs only one specific operation. Processing parts using the first method is called the method of concentrated (enlarged) operations, and according to the second - the method of differentiated (dismembered) operations.

A distinctive feature of the enlarged processing method is the combination of several transitions in one more complex operation. For example, reducing the number of rearrangements of parts on a machine and performing a given processing in one installation, simultaneous drilling of several holes in different planes, etc. The highest degree of development of the method of enlarging an operation is multi-position processing of parts on automatic production lines and on modular machines, which is characteristic for mass and large-scale production.

However, the method of consolidating operations is also successfully used in conditions of single and small-scale production: when processing heavy and large parts, in the presence of clamping devices that require great physical effort from the worker when fastening parts, when installing complex workpieces, the correct alignment of which requires a lot of time. etc. At the same time, higher qualifications of workers are required and higher demands are placed on the workplace. The combination of several operations on one machine is facilitated by the use of multiple devices, multiple spindle heads, and combined tools (combined drills, countersinks, etc.).

1.Machine as an object of production

Mechanical engineering is one of the leading sectors of the national economy. The objects of production of the mechanical engineering industry are various types of machines. The concept of a “machine” has been formed over many centuries as science and technology develop. Since ancient times, a machine has been understood as a device designed to allow the forces of nature to operate in it in accordance with human needs. Currently, the concept of “machine” has expanded and is interpreted from different positions and in different senses. For example, from the point of view of mechanics, a machine is a mechanism or a combination of mechanisms that perform purposeful movements to transform energy, materials, or produce work.

The emergence of electronic computers, spontaneously classified as machines, forced us to consider a machine as a device that performs certain appropriate mechanical movements to convert energy, materials, perform work, or to collect, transmit, store, process and use information. All machines and various mechanical devices were created with the aim of replacing or facilitating human physical and mental labor. From the point of view of mechanical engineering technology, a machine can be either an object or a means of production. Therefore, for mechanical engineering technology, the concept of “machine” can be defined as a system created by human labor for the qualitative transformation of the original product into products useful for humans. The transformation process can be carried out mechanically, physically, chemically, either individually or in combination. Depending on the area of ​​use and functional purpose, energy, production and information machines are distinguished.

In energy machines, one type of energy is converted into another. Such machines are usually called engines. Hydraulic turbines, internal combustion engines, steam and gas turbines are classified as so-called heat engines. Electric motors, direct and alternating current, form a group of electrical machines. The number of types of production machines is quite large. This is due to the variety of production processes performed by these machines. There are construction, lifting, earth-moving, transport and other machines. The largest group consists of technological or working machines. These include, for example, metal-cutting machines, textile and paper-making machines, printing equipment, etc. Technological machines are characterized by periodically repeated movements of their working parts, which directly perform production operations. Mechanical energy must be continuously supplied to the working parts of the machine. In this case, the engine (most often electric) and the working parts of the machine are connected using special devices called mechanisms. Mechanisms are an integral part of both energy and production machines.

Modern energy machines use simple types of movements (rotational, reciprocating), so they use a small number of types of mechanisms. On the contrary, the number of types of mechanisms used in modern production machines is quite large. This is explained by the wide variety of types of movements of their working organs. The engine machine, transmission mechanism and actuator machine, designed as one unit and mounted on a common frame or foundation, constitute a machine unit. Of great importance for the development of all branches of modern production is the increasingly widespread introduction of methods for automatic control of production processes. The devices used for this purpose are called instruments. A separate group of devices that change the state of the object of labor without the direct participation of the worker are devices.

In the devices, various chemical, thermal, electrical and other processes take place that are necessary to process or change the properties of the parts being processed. The working devices of the devices are, as a rule, stationary. Sometimes the devices include devices for transporting objects being processed (conveyors for thermal furnaces, various loading and dosing devices, etc.). The group of information machines consists of computing, measuring, control and management, etc. Energy and information machines are studied in special courses in the relevant specialties. Machines, mechanisms, individual components and parts in the process of their production at a machine-building enterprise are products. In mechanical engineering, a product is any item or set of production items to be manufactured at a given enterprise.

A product can be a machine, its assembled elements and individual parts, if they are a product of the final stage of this production. For example, for an automobile plant the product is a car, for a gearbox plant it is a gearbox, for a piston plant it is a piston, etc. Products can be unspecified (having no component parts) or specified (consisting of two or more parts). A part is a product made from a material that is homogeneous by name and brand without the use of assembly operations. A characteristic feature of the part is the absence of detachable and permanent connections. A part is a complex of interconnected surfaces that perform various functions during machine operation. Machine parts for various functional purposes differ in shape, size, material, etc. At the same time, regardless of the functional purpose, machine parts have a common production property: they are a product of production, forming them from initial blanks and materials.

In addition to individual machines and their parts, the objects of production of machine-building enterprises can be complexes and sets of products. A complex is two or more specified products that are not connected at the manufacturing plant by assembly operations, but are intended to perform interrelated operational functions, for example: a drilling rig, an automatic line, an automatic workshop, etc. A set is two or more products that are not connected at the manufacturing plant by assembly operations and represent a set of products that have a general operational purpose of an auxiliary nature, for example: a set of spare parts, a set of tools and accessories, a set of measuring equipment, etc. A group of component parts of a product that must be submitted to the workplace to assemble a product or its component is called an assembly kit. The product of the supplier company, used as an integral part of the product produced by the manufacturer, is called a component product. For a motor plant, the components can be, for example, starters, generators, breaker-distributors, etc. One of the most important characteristics of the products produced is their quality. Moreover, in accordance with GOST 1546779, the quality of industrial products is understood as a set of properties that determine its suitability to satisfy certain needs in accordance with its purpose. Product quality is fixed for a certain period of time using various regulatory documents, mainly standards, and changes with the advent of more advanced technologies. Product quality is one of the most important indicators of production and economic activity of an industrial enterprise. It is the quality of products that determines the financial and economic stability of the enterprise, the pace of scientific and technological progress, and the saving of material and labor resources. In all countries of the world, the production of high-quality products is considered one of the most important conditions for the development of the national economy. A decrease in quality leads to a decrease in sales, profits and profitability, a decrease in exports and other undesirable consequences.

2. Production process and its structure

Industrial production is the largest and leading area of ​​the sphere of material production. It is a system of interconnected industries engaged in the extraction and processing of industrial and agricultural raw materials into finished products necessary for public production and personal consumption. Mechanical engineering production is based on the primary use of mechanical engineering technology methods in the production of products. The main products of mechanical engineering are metal-cutting machines, cars, tractors, agricultural machines, defense products, energy equipment, construction equipment and other types of machines and mechanisms. Mechanical engineering production as a whole consists of many organizationally and economically independent production units called mechanical engineering enterprises. A machine-building enterprise is a complex, purposeful system that unites people and production tools to ensure the production of products.

The process of manufacturing machines and mechanisms at a machine-building enterprise consists of a set of works, as a result of which raw materials and semi-finished products are transformed into a finished product. A machine-building plant can receive certain types of raw materials, parts and assemblies (bearings, electric motors, hydraulic automation, rubber products, etc.) as components from other industrial enterprises. The totality of all actions of people and production tools necessary for the manufacture or repair of products at a given enterprise is called the production process. The production process of modern machine-building enterprises is a single interconnected set of works, covering the preparation of production means and the organization of maintenance of workplaces, the processes of obtaining initial blanks and finished parts, the processes of assembly, testing, technical control, storage, transportation, packaging and marketing of finished products, as well as other types of work related to the production of products. Depending on the meaning and role in the manufacture of products, main, auxiliary and servicing production processes are distinguished. The main process ensures the production of marketable products. It is directly related to the manufacture of parts and the assembly of machines and mechanisms from them. During the main production processes, raw materials and materials are transformed into finished products of a given quality. The main production includes, for example, processing of workpieces on metal-cutting machines, chemical and chemical-thermal treatment, forging, stamping, welding, assembly, etc.

Auxiliary processes ensure stable and rhythmic operation of the main process and are engaged in the manufacture of products and provision of services necessary for the main production. These works include, for example, the manufacture of metal-cutting tools and technological equipment, adjustment and repair of equipment, the manufacture of control and measuring instruments, tool sharpening, providing the enterprise with electrical and thermal energy, compressed air, carbon dioxide, oxygen, acetylene and other types of work. Products of the main production are intended for sale under contracts and on the free market, and products of auxiliary production are used only within the manufacturing enterprise. Maintenance processes must ensure the uninterrupted and rhythmic operation of all departments of the enterprise. These include inter- and intra-shop transport, loading and unloading operations, warehousing and storage of raw materials, materials, components, cleaning of workshops and the territory of the enterprise. This also includes factory laboratories, medical institutions, canteens, etc.

Depending on the technical equipment, i.e. Depending on the participation of the worker, production processes are divided into manual, manual mechanized, machine-manual, machine, automated and instrumental. In the case of manual processes, the impact on the object of labor is carried out by the worker using any tools, but without the use of any energy sources. This is, for example, tightening a nut with a wrench or drilling a hole with a hand drill.

Manual mechanized processes are characterized by the fact that technological operations are performed by workers using hand-held mechanized tools, that is, using any energy sources, for example, drilling holes with an electric drill, cleaning castings with a portable emery wheel, etc. Machine-manual processes include processes when the impact on the object of labor is carried out using a machine or mechanism, but with the obligatory participation of a worker, for example, drilling a hole on a drilling machine with manual feed.

Machine processes are carried out on machines, machine tools and other types of technological equipment without the direct participation of the worker, and the role of the worker in this case is to provide the machine with material, remove finished products, start and stop equipment, etc.

Automated production processes are carried out on automatic machines, automated production lines and other types of automated equipment, and the role of the worker in this case is reduced to monitoring the progress of the process and performing commissioning work. Hardware processes take place when the object of labor is exposed to any type of thermal, chemical, or electrical energy. These types of processes include, for example, metallurgical processes, thermal and chemical-thermal treatment, steam preparation, drying, and various chemical processes. In this case, workers observe the operation of the devices and, if necessary, intervene in the processes occurring in them. Depending on the stage of manufacture, i.e. depending on the place in the product manufacturing process, procurement, processing and assembly production processes are distinguished. Procurement processes transform raw materials into raw materials that are similar in shape and size to finished parts.

In mechanical engineering, these are, for example, foundries, forging and stamping shops, and shops for the primary processing of rolled products. Processing are processes during which blanks are transformed into finished parts, the shape, dimensions and properties of which are specified by the designer in the drawing. This phase includes processing of workpieces on metal-cutting machines, thermal and chemical-thermal treatment, galvanic, painting and other work. Assembly of components, assemblies and individual parts into finished products is carried out in separate workshops or in separate sections of workshops. In addition, the production process includes quality control, regulation and testing of manufactured products, i.e. checking those parameters that determine its quality, purpose and application.

The production activities of the plant are carried out by its constituent workshops, sections, various services and divisions in which the main products, components, materials and semi-finished products, spare parts for servicing and repairing products during operation are manufactured, undergo control checks and tests. The workshop is the main production unit of a machine-building enterprise. Moreover, according to GOST 14.00483, a workshop is understood as a set of production areas. The workshop is characterized by the performance of work of a technologically homogeneous type, the presence of a certain type of technological equipment and certain types of worker professions. For example, in machine shops they process machine parts by cutting on metal-cutting machines; the professions of workers are turners, millers, drillers, boring machines, etc.

A workshop is an administratively separate unit that performs a certain part of the overall production process of manufacturing products. The workshops carry out their activities on the principles of economic accounting. A production site is a group of workplaces organized according to subject, technological or subject-technological principles. Depending on the functions performed and the role in the manufacture of products, workshops are usually divided into production, auxiliary and service. In addition, almost every machine-building enterprise has departments dedicated to improving the production qualifications of workers, engineers and specialists. The composition of the workshops and services of an enterprise, indicating the connections between them, is called its production structure.

A special role in the production structure of the enterprise is played by design bureaus, research and testing stations. They develop designs for new products, new technological processes, conduct experimental research and development work, refine the product design, etc. The production structure of a workshop is determined mainly by the design and technological features of the workshop's products, the volume of output, the form of specialization of the workshop and its cooperation with other workshops. The main elements of the production structure of the workshop are the sections and lines that ensure the production of parts and the assembly of components and products that make up the production program of the workshop and plant. In addition to the main production areas and lines, the workshops also include auxiliary departments and services that ensure the functioning of production areas. These are, for example, departments and areas for the restoration of cutting tools, their repair, a workshop repair base for the maintenance and repair of equipment, collection and processing of chips, control and testing departments, etc. The main production areas can be created according to the principle of technological and subject specialization.

At sites organized according to the principle of technological specialization, technological operations of a certain type are performed. For example, in a mechanical shop, turning, milling, grinding, metalworking and other areas can be organized, in assembly areas for the unit and final assembly of products, testing of their parts and systems, control and testing stations, etc. In areas organized according to the principle of subject specialization, carry out not individual types of operations, but technological processes as a whole, as a result of which they obtain finished products for a given section. For example, a section is allocated for processing body parts, shafts, gears and worm wheels, hardware, etc. In some cases, a workshop or site is assigned the technological process of manufacturing a separate product or some limited range of products, for example, workshops for gearboxes, couplings, gearboxes, etc. In this case, parts and assemblies are distributed among separate workshops or sections of workshops depending on their weight, complexity, functional purpose or other characteristics. The installation and location of equipment in such areas is carried out during the technological process of manufacturing certain parts or finished products.

Machine-building enterprises, depending on the degree of their technological specialization, are divided into two types.

1. Enterprises that fully cover all stages of the product manufacturing process. Such an enterprise includes the main enterprises at all stages of the production process, from procurement to assembly inclusive.

2. Enterprises that do not fully cover all stages of product manufacturing. The production structure of such an enterprise lacks some workshops related to one or another stage of the main production process. Such an enterprise can only have main procurement shops that produce castings, forgings or stampings, supplied through cooperation to other machine-building enterprises; or only assembly shops that assemble products from parts and assemblies supplied through cooperation by other enterprises; or only machining shops, which manufacture parts or assemblies from blanks received from other enterprises and transfer them for final assembly and testing to other machine-building enterprises.

Enterprises with an incomplete production structure usually have a higher level of technological specialization than enterprises with a complete production structure. A rationally organized technological process for manufacturing a product must ensure the specified product quality and labor productivity, as well as the rhythm of work, stability of quality over time and production of products in the required volume. When addressing issues of production development, its technical re-equipment and reconstruction, it is especially important to correctly identify the most promising production facilities and the market need for these facilities both in the near future and in the long term. All scientific, technical, production and sales activities of the enterprise should be aimed at producing competitive and in-demand products, including on the world market.

3. Technological process and its structure

The most important element of the production process is the technological process. A technological process is a part of the production process that contains targeted actions to change and subsequently determine the state of the subject of labor. A change in the state of an object of labor is understood as a change in its physical, mechanical, chemical properties, geometric dimensions, and appearance. Depending on the content, technological processes for obtaining blanks, manufacturing parts, assembling individual components and the machine as a whole, painting the machine, etc. are distinguished. Subsequent determination of the state of the object of labor means consistent monitoring of the production “change” of the object of production.

According to the sequence of execution, technological processes of manufacturing initial blanks, their processing and assembly of products are distinguished. In the technological process of manufacturing blanks, the material is converted into the original blanks of machine parts by casting, pressure treatment, cutting of long products, as well as combined methods. As a result of the technological processing process in a certain sequence, a direct change in the state of the processed workpiece occurs, i.e. change in its size, shape or physical and mechanical properties. In this case, processing is understood as an action aimed at changing the properties of the object of labor when performing a technological process.

Individual types of processing include, for example, cutting, pressure processing, heat treatment, surface hardening of parts, etc. The set of values ​​of technological process parameters in a certain time interval is called a technological mode. In cutting processing, for example, the parameters of the technological mode are cutting speed, depth of cut and feed; during heat treatment, heating rate, heating temperature, holding time and subsequent cooling rate. The technological process can be carried out in the presence of appropriate production tools, called technological equipment. In this case, technological equipment includes technological equipment and technological equipment.

Technological equipment refers to means of technological equipment in which materials or workpieces, means of influencing them, as well as technological equipment are placed to perform a certain part of the technological process. Technological equipment includes, for example, casting machines, metal-cutting machines, heating furnaces, galvanic baths, forging hammers, test benches, etc. Technological equipment refers to means of technological equipment that complement technological equipment to perform a certain part of the technological process. Technological equipment includes cutting tools, dies, fixtures, measuring instruments, models, casting molds, etc.

The degree of progressivity of the technological process can be assessed by qualitative and quantitative indicators. A qualitative indicator of the progressiveness of a technological process characterizes its basic idea, the technical method for implementing this idea, as well as the degree of approximation of the real technological process to its model, which can be developed taking into account the latest achievements of science and technology. On the quantitative side, the progressiveness of the technological process can be assessed by a system of indicators, the main of which, according to GOST 2778288, are the material utilization coefficient, consumption coefficient, and material cutting coefficient. The material utilization coefficient characterizes the degree of useful consumption of material for the production of a product. The consumption coefficient is the inverse indicator of the material utilization coefficient. The material cutting coefficient characterizes the degree of use of the mass (area, length, volume) of the source material during cutting in relation to the mass (area, length, volume) of all types of resulting blanks or parts. The maximum permissible planned amount of material for the manufacture of a product under the established quality and production conditions is the rate of material consumption for the product.

The consumption rate should take into account the mass of the product (useful consumption of material), process waste and material loss. Waste can be used as a starting material for the production of other products or sold as secondary raw materials. Material losses characterize the amount of irretrievably lost material during the manufacturing process of a product. The mass of technological waste and material losses is regulated in the technological documentation.

It was previously noted that the production of machines at machine-building enterprises is carried out as a result of the implementation of a set of interrelated technological processes that are parts of the overall production process of the enterprise. To carry out the technological process, a workplace is created, which is a section of the production area of ​​the workshop, equipped in accordance with the work performed on it. The workplace is an elementary unit of the enterprise structure, where the performers of the work, serviced technological equipment, part of the conveyor, devices for storing workpieces and products manufactured at this workplace, and, for a limited time, technological equipment and labor items are located. T

A technological process is usually divided into parts called operations. A technological operation is a completed part of a technological process performed at one workplace. An operation covers all actions of equipment and workers on one or more jointly processed or assembled production objects. So, when processing on machines, the operation includes all the actions of the worker to control the machine, as well as automatic movements of the machine associated with the process of processing the workpiece until it is removed from the machine and proceeds to processing another workpiece. The number of operations in the technological process depends on the complexity of the design of the part or assembled product and can vary within fairly wide limits.

Individual processing operations include, for example, drilling, turning, milling, reaming, tapping, etc. As you can see, the operation is characterized by the invariance of the workplace, technological equipment, subject of labor and performer. When one of these conditions changes, a new operation takes place. However, a change in workplace is not always a criterion for the completion of an operation. For example, processing on two duplicate drilling machines, where the constant presence of one worker is necessary near each machine, means the presence of two jobs, but the same operation is performed if the same processing is performed on these machines with the same equipment setup. If rough processing of a part, for example, is performed by one worker on one machine, and finishing by another worker on another machine, then two operations are performed here. If both roughing and finishing are performed on the same machine, then this will be one operation. Turning a shaft, carried out successively first at one end and then after reinstalling it on the centers at the other, is one operation.

It should be noted that the transition to processing another workpiece does not mean the start of a new operation. The workpiece may be from the same batch as the previous one. In this case, the operation is the same, but is repeated as many times as there are blanks in the batch. Therefore, the main criterion for another operation is the readjustment of the machine, i.e. completeness of the processing process. The need to divide the technological process into operations is mainly due to two factors. It is usually impossible to process a workpiece from all sides in one workplace. In addition, when constructing a technological process based on the principle of differentiation, it becomes necessary to separate the preliminary and final mechanical processing of the workpiece, since heat treatment must be carried out between them. On the other hand, for economic reasons, it is inappropriate, for example, to create a special and expensive machine that allows you to combine many methods of machining at one workplace. In large-scale and mass production, when assembling a large number of identical products, the division of the assembly process into separate operations and the assignment of each of them to a separate workplace determines the narrow specialization of workers in performing operations, which ensures higher labor productivity and allows the use of relatively low-skilled workers.

The content of the operation is determined by many factors and, above all, factors of an organizational and economic nature. The range of work included in the operation can be quite wide. The operation may consist of processing just one surface on a separate machine. For example, milling a keyway on a vertical milling machine. The production of a complex body part on an automatic line, consisting of several dozen machines and having a unified control system, is also an operation. A technological operation is the main element of production planning and accounting. Based on the operations, the labor intensity of the process, the necessary equipment, tools, devices, and the qualifications of workers are determined. For each operation, all planning, accounting and technological documentation is drawn up.

The operations included in the technological process are performed in a certain sequence. The content, composition and sequence of operations determine the structure of the technological process. The sequence of passage of a workpiece, part or assembly unit through the workshops and production areas of an enterprise during the technological process of manufacturing or repair is called a technological route. The structure of the operation involves dividing it into its component elements of installation, positions and transitions. To process a workpiece, it must be installed and secured in a fixture, on a machine table or other type of equipment. When assembling, the same should be done with the part to which other parts must be attached. Established part of the technological operation, performed with constant fastening of the processed workpieces or assembled assembly unit. Each time the workpiece is removed again and then secured on the machine, or when the workpiece is rotated at any angle to process a new surface, a new setting takes place.

Depending on the design features of the product and the content of the operation, it can be performed either from one or from several installations. In the technological documentation, installations are designated by the letters A, B, C, etc. For example, when processing a shaft on a milling and centering machine, milling the ends of the shaft on both sides and aligning them is performed sequentially in one installation of the workpiece. Complete processing of the shaft workpiece on a screw-cutting lathe can be carried out only from two workpiece installations in the centers, since after processing the workpiece on one side (installation A), it must be unfastened and installed in a new position (installation B) for processing on the other side. If the workpiece is rotated without removing it from the machine, it is necessary to indicate the rotation angle: 45°, 60°, etc.

An installed and secured workpiece, if necessary, can change its position on the machine relative to the tool or working parts of the machine under the influence of linear movement devices or rotary devices, taking a new position. A position is each individual fixed position occupied by a permanently fixed workpiece or assembled assembly unit together with a fixture relative to a tool or a stationary piece of equipment when performing a certain part of the operation. When processing a workpiece, for example, on a turret lathe, the position will be each new position of the turret head.

When processing on multi-spindle automatic and semi-automatic machines, the invariably fixed workpiece occupies different positions relative to the machine by rotating the table, which sequentially brings the workpiece to different tools. Technological transition is a completed part of a technological operation, performed by the same means of technological equipment under constant technological conditions and installation. The technological transition, therefore, characterizes the constancy of the tool used, the surfaces formed by processing or connected during assembly, as well as the constancy of the technological regime. For example, technological transitions will be obtaining a hole in a workpiece by processing with a twist drill, obtaining a flat surface of a part by milling, etc. Sequential processing of the same hole in the gearbox housing with a boring cutter, countersink and reamer will consist of three technological transitions, respectively, since during processing with each tool a new surface is formed.

In a turning operation, two technological transitions are performed. Such transitions are called simple or elementary. A set of transitions, when several tools are simultaneously involved in the work, is called a combined transition. In this case, all tools work with the same feed and at the same speed of rotation of the workpiece. In the case when a change occurs in successively processed surfaces with one tool with a change in cutting modes (speed when processing on hydrocopying machines or speed and feed on CNC machines) with one working stroke of the tool, a complex transition occurs. Technological transitions can be carried out sequentially or parallel-sequentially. When processing workpieces on CNC machines, several surfaces can be sequentially processed by one tool (for example, a scoring cutter) as it moves along a trajectory specified by the control program. In this case, they say that the specified set of surfaces is processed as a result of performing a tool transition.

Examples of technological transitions in assembly processes include work related to connecting individual machine parts: giving them the required relative position, checking the achieved position and fixing it with fasteners. In this case, the installation of each fastener (for example, a screw, bolt or nut) should be considered as a separate technological transition, and the simultaneous tightening of several nuts using a multi-spindle impact wrench as a combination of technological transitions. A technological operation, depending on the organization of the technological process, can be carried out on the basis of concentration or differentiation of technological transitions. With the concentration of transitions, the structure of the operation includes the maximum possible number of technological transitions under given conditions. This organization of the operation reduces the number of operations in the technological process. In the limiting case, the technological process can consist of only one technological operation, including all the transitions necessary for the manufacture of the part. When differentiating transitions, one strives to reduce the number of transitions included in a technological operation.

The limit of differentiation is such a construction of the technological process when each operation includes only one technological transition. A characteristic feature of technological transition in any process (except hardware) is the possibility of its isolation at a separate workplace, i.e. isolating it as an independent operation. In the case of a one-transition operation, the concept of an operation may coincide with the concept of a transition. When organizing the processing process according to the principle of differentiation of the construction of an operation (and not a transition), the technological process is divided into one- and two-transition operations, subordinate in duration to the release cycle. If operations (for example, gear hobbing, spline milling) last beyond the exhaust cycle, then backup machines are installed. Consequently, the limit of differentiation is the release stroke. The principle of concentration of operations is divided into the principle of parallel concentration and sequential one. In both cases, a large number of technological transitions are concentrated in one operation, but they are distributed among positions in such a way that the processing time for each operation is approximately equal to or less than the production cycle.

Based on the longest time for positions, the time norm for the operation will be determined. According to the principle of sequential concentration, all transitions are performed sequentially, and the processing time is determined by the total time for all transitions. A technological transition during cutting processing can consist of several working strokes. A working stroke is understood as the completed part of a technological transition, consisting of a single movement of the tool relative to the workpiece, accompanied by a change in the shape, size, surface quality or properties of the workpiece. The number of working strokes performed in one technological transition is selected based on ensuring optimal processing conditions, for example, reducing the cutting depth when removing significant layers of material. An example of a working stroke on a lathe is the removal of one layer of chips continuously with a cutter, the removal of one layer of metal over the entire surface on a planer, and the drilling of a hole to a given depth on a drilling machine. Working strokes occur in cases where the amount of allowance exceeds the possible depth of cut and it has to be removed in several working strokes. When repeating the same work, for example, drilling four identical holes sequentially, there is one technological transition performed in 4 working strokes; if these holes are made simultaneously, then there are 4 combined working strokes and one technological transition. The operation also includes elements associated with the implementation of auxiliary movements and necessary for the implementation of the technological process. These include auxiliary transitions and techniques. 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 or surface properties, but are necessary to perform a technological transition.

Auxiliary transitions include, for example, securing a workpiece on a machine or in a fixture, changing a tool, moving a tool between positions, etc. For assembly processes, auxiliary transitions can be considered transitions for installing a base part on an assembly stand or in a fixture on a conveyor, moving parts attached to it etc. To perform a technological operation, auxiliary moves and techniques are also necessary. An auxiliary stroke is a completed part of a technological transition, consisting of a single movement of the tool relative to the workpiece, necessary to prepare the working stroke. A technique is understood as a complete set of worker actions used when performing a transition or part of it and united by one purpose. For example, the auxiliary transition “install the workpiece in the fixture” consists of the following techniques: take the workpiece from the container, install it in the fixture, secure it. Auxiliary moves and techniques are taken into account when studying the cost of auxiliary time to perform an operation. Any technological process takes place over time. The calendar time interval from the beginning to the end of any periodically repeating technological operation, regardless of the number of simultaneously manufactured or repaired products, is called the technological operation cycle.

The preparation of technological equipment and technological equipment for performing a technological operation is called adjustment. Adjustments include installing the fixture, switching the speed or feed, setting the set temperature, etc. Additional adjustment of technological equipment and (or) equipment during operation to restore the parameter values ​​achieved during adjustment is called sub-adjustment.

4. Types of production and their characteristics

Mechanical engineering production is characterized by output volume, product release program, and production cycle. The volume of production is the number of products of certain names, standard sizes and designs manufactured or repaired by an enterprise or its division during a planned period of time (month, quarter, year). The volume of output largely determines the principles of constructing the technological process. The list of manufactured or repaired products established for a given enterprise, indicating the volume of production and deadlines for each item for the planned period of time, is called a production program.

A release cycle is the time interval through which products or blanks of a certain name, standard size and design are periodically produced. The production cycle t, min/piece, is determined by the formula t = 60 Fd/N, where Fd is the actual time fund in the planned period (month, day, shift), h; N production program for the same period, pcs. The actual operating time fund of equipment differs from the nominal (calendar) time fund, since it takes into account the loss of time for equipment repairs. The actual operational capacity of equipment, depending on its complexity and the number of weekends and holidays with a 40-hour work week and when working in two shifts in mechanical engineering, ranges from 3911 to 4029...4070 hours. The worker's time fund is about 1820 hours.

Depending on production capacity and sales opportunities, products at the enterprise are manufactured in various quantities from single copies to hundreds and thousands of pieces. In this case, all products manufactured according to design and technological documentation without changing it are called a product series. Depending on the breadth of the range, regularity, stability and volume of product output, three main types of production are distinguished: single, serial and mass. Each of these types has its own characteristic features in the organization of labor and in the structure of production and technological processes. Type of production is a classification category of production, distinguished on the basis of breadth of product range, regularity, stability and volume of production. In contrast to the type of production, the type of production is distinguished based on the method used to manufacture the product. Examples of types of production are foundry, welding, mechanical assembly, etc. One of the main characteristics of the type of production is the coefficient of consolidation of operations Кз.о., which is the ratio of the number of all different technological operations ΣО, performed or to be performed during the month, to the number of jobs ΣР : Kz.o. = ΣО/ΣР With the expansion of the range of manufactured products and a decrease in their quantity, the value of this coefficient increases.

Single production is characterized by a small volume of production of identical products, the re-production and repair of which, as a rule, is not provided. In this case, the technological process of manufacturing products is either not repeated at all, or is repeated at indefinite intervals. The single type of production produces, for example, large hydraulic turbines, rolling mills, equipment for chemical and metallurgical plants, unique metal-cutting machines, prototypes of machines in various branches of mechanical engineering, repair shops and areas, etc.

Unit production technology is characterized by the use of universal metal-cutting equipment, which is usually located in workshops according to a group basis, i.e. broken down into sections of turning, milling, grinding machines, etc. Processing is carried out with a standard cutting tool, and control is carried out with a universal measuring tool. A characteristic feature of unit production is the concentration of various operations at workplaces. In this case, one machine often performs complete processing of workpieces of various designs and from various materials. Due to the need for frequent reconfiguration and adjustment of the machine to perform a new operation, the share of the main (technological) time in the overall structure of the standard processing time is relatively small.

The distinctive features of unit production determine relatively low labor productivity and high cost of manufactured products. Batch production is characterized by the manufacture or repair of products in periodically repeated batches. In mass production, products of the same name or the same type in design are manufactured according to drawings that have been tested for manufacturability. Series production products are machines of an established type, produced in significant quantities. These products include, for example, metal-cutting machines, internal combustion engines, pumps, compressors, equipment for the food industry, etc. Serial production is the most common in general and medium-sized mechanical engineering.

In serial production, along with universal equipment, special equipment, automatic and semi-automatic machines, CNC machines, special cutting tools, special measuring instruments and devices are widely used. In mass production, the average qualification of workers is usually lower than in individual production. Depending on the number of products in a batch or series and the value of the consolidation coefficient of operations, small-scale, medium-scale and large-scale production are distinguished. Such a division is quite arbitrary for various branches of mechanical engineering, since with the same number of machines in a series, but of different sizes, complexity and labor intensity, production can be classified as different types. The conventional boundary between the varieties of serial production according to GOST 3.110874 is the value of the coefficient of consolidation of operations Kz.o.: for small-scale production 20< Кз.о.< 40, для среднесерийного ­ 10 < Кз.о.< 20, а для крупносерийного ­ 1 < Кз.о.< 10.

In small-scale production, close to a single unit, the equipment is located mainly by type of machine - a section of lathes, a section of milling machines, etc. Machines can also be located along the technological process if processing is carried out according to a group technological process. Mainly universal means of technological equipment are used. The production batch size is usually several units. In this case, a production batch is usually called objects of labor of the same name and standard size, launched into processing within a certain time interval, with the same preparatory and final time for the operation. In medium-scale production, usually called serial production, equipment is located in accordance with the sequence of workpiece processing stages. Each piece of equipment is usually assigned several technological operations, which makes it necessary to re-adjust the equipment. The production batch size ranges from several tens to hundreds of parts.

In high-volume, near-volume production, equipment is typically arranged in a process sequence for one or more parts that require the same machining process. If the product production program is not large enough, it is advisable to process workpieces in batches, with sequential operations, i.e. After processing all the blanks of a batch in one operation, this batch is processed in the next operation. After finishing processing on one machine, the workpieces are transported as a whole batch or in parts to another, while roller conveyors, overhead chain conveyors or robots are used as vehicles. Processing of workpieces is carried out on pre-configured machines, within the technological capabilities of which readjustment to perform other operations is permissible. In large-scale production, as a rule, special devices and special cutting tools are used. Limit gauges (staples, plugs, threaded rings and threaded plugs) and templates are widely used as measuring tools, which make it possible to determine the suitability of processed parts and break them down into size groups depending on the size of the tolerance zone.

Serial production is much more economical than individual production, since equipment is used better, allowances are lower, cutting conditions are higher, jobs are highly specialized, the production cycle, interoperational backlogs and work in progress are significantly reduced, a higher level of production automation, labor productivity increases, sharply decreases labor intensity and cost of products, simplifies production management and labor organization. In this case, the reserve is understood as a production stock of blanks or component parts of the product to ensure the uninterrupted execution of the technological process. This type of production is the most common in general and medium-sized engineering. About 80% of mechanical engineering products are mass-produced. Mass production is characterized by a large volume of products that are continuously manufactured or repaired over a long period of time, during which one work operation is performed at most workplaces.

Parts are usually made from blanks, the production of which is carried out centrally. The production of non-standard equipment and technological equipment is carried out in a centralized manner. The workshops, which are an independent structural unit, supply them to their consumers. Mass production is economically feasible when producing a sufficiently large number of products, when all material and labor costs associated with the transition to mass production pay off quickly enough and the cost of the product is lower than in mass production. Mass production products are products of a narrow range, unified or standard type, produced for wide distribution to consumers. These products include, for example, many brands of cars, motorcycles, sewing machines, bicycles, etc.

In mass production, high-performance technological equipment is used: special, specialized and modular machines, multi-spindle automatic and semi-automatic machines, and automatic lines. Multi-bladed and stacked special cutting tools, extreme gauges, high-speed control devices and instruments are widely used. Mass production is also characterized by a steady production volume, which, with a significant production program, provides the opportunity to assign operations to specific equipment. At the same time, the production of products is carried out according to the final design and technological documentation. The most advanced form of organizing mass production is flow production, characterized by the arrangement of technological equipment in the sequence of operations of the technological process and a certain cycle of product release. The flow form of organizing the technological process requires the same or multiple productivity in all operations. This makes it possible to process workpieces or assemble units without backlogs at strictly defined time intervals equal to the release cycle. Bringing the duration of operations to the specified condition is called synchronization, which in some cases involves the use of additional (duplicate) equipment. For mass production, the coefficient of consolidation of operations Kz.o. = 1.

The main element of continuous production is the production line on which the workplaces are located. To transfer the subject of labor from one workplace to another, special vehicles are used. In a production line, which is the main form of labor organization in continuous production, one technological operation is performed at each workplace, and the equipment is placed along the technological process (along the flow). If the duration of the operation at all workplaces is the same, then work on the line is performed with the continuous transfer of the production object from one workplace to another (continuous flow). It is usually not possible to achieve equality of piece time in all operations. This causes a technologically inevitable difference in equipment loading at work stations on the production line. With significant output volumes during the synchronization process, the need most often arises to reduce the duration of operations. This is achieved through differentiation and time combination of transitions that are part of technological operations. In mass and large-scale production, if necessary, each of the technological transitions can be separated into a separate operation if the synchronization condition is met. In a time equal to the production cycle, a unit of product leaves the production line.

Labor productivity corresponding to a dedicated production site (line, section, workshop) is determined by the rhythm of production. The rhythm of production is the number of products or blanks of certain names, standard sizes and designs produced per unit of time. Ensuring a given rhythm of production is the most important task when developing a technological process for mass and large-scale production. The flow method of work provides a significant reduction (tens of times) in the production cycle, interoperational backlogs and work in progress, the possibility of using high-performance equipment, reducing the labor intensity of manufacturing products, and ease of production management. Further improvement of flow production led to the creation of automatic lines, on which all operations are carried out at a set pace at workstations equipped with automatic equipment. Transportation of the subject of labor to positions is also carried out automatically. The calendar time interval from the beginning to the end of the process of manufacturing or repairing a product is called the production cycle. The duration of the production cycle and the rhythm of the enterprise's work largely depend on the organization of the entire production process, clear management of production and personnel, timely supply of the enterprise with raw materials, supplies, tools, spare parts, components and other means of production. The timely sale of manufactured industrial products is important for the rhythm and efficiency of the enterprise. It should be noted that at one enterprise and even in one workshop one can find a combination of different types of production.

Consequently, the type of production of an enterprise or workshop as a whole is determined by the predominant nature of technological processes. Production can be called mass production if most workplaces perform one constantly repeating operation. If the majority of workplaces perform several periodically repeating operations, then such production should be considered serial production. The absence of frequency of repetition of operations at workplaces characterizes unit production. In addition, each type of production is also characterized by the corresponding accuracy of the initial workpieces, the level of refinement of the design of parts for manufacturability, the level of automation of the process, the degree of detail in the description of the technological process, etc. All this affects the productivity of the process and the cost of manufactured products. The systematic unification and standardization of mechanical engineering products contributes to the specialization of production. Standardization leads to a narrowing of the range of products with a significant increase in their production program. This allows for the wider use of in-line work methods and production automation. Production characteristics are reflected in decisions made during technological preparation of production.

Conclusion

Basics of production organization. The organization of production is understood as the coordination and optimization in time and space of all material and labor elements of production in order to achieve the greatest production result at the lowest cost within a certain time frame. Consequently, the organization of production creates conditions for the best use of technology and people in the production process, thereby increasing its efficiency. Each industrial enterprise has its own specific tasks for organizing production. These may be, for example, issues of providing raw materials, the best use of labor, raw materials, equipment, improving the range and quality of products, developing new types of products, etc. Since in practice many problems of production organization are solved by technology, it is important to distinguish between the functions of technology and the functions of production organization.

Technology determines the methods and options for manufacturing products. The function of the technology is to determine the possible types of equipment and technological equipment for the production of each type of product, as well as the optimal parameters of the technological regime. Thus, technologies determine what needs to be done with an object of labor and with what means of production in order to turn it into a product with given properties. The function of organizing production is to determine specific values ​​of technological process parameters based on an analysis of possible options and selection of the most effective in accordance with the purpose and conditions of production. That is, the organization of production determines how best to combine the subject and tools of labor, as well as the labor itself, in order to transform the subject of labor into a product of the necessary properties with the least expenditure of labor and means of production.

Features of the organization of production are the consideration of the interconnection of production elements and the selection of such methods and conditions for their use that best correspond to the purpose of production. Many issues of production organization are considered in conjunction with technology. However, the organization of production also has unique tasks. This, in particular, is deepening specialization, rapid (flexible) reorientation of production to other types of products, ensuring continuity and rhythm of the production process, improving the forms of organization of production, etc. In addition, the tasks of organizing production include reducing the duration of the production cycle, uninterrupted supply of raw materials, materials, components, sales of finished products, reducing equipment downtime and ensuring its optimal loading, coordination of all parts of the production process, etc.

The set of departments and services involved in building and coordinating the functioning of the production process is called the organizational structure of the enterprise. The economic efficiency of the production structure can be assessed by such indicators as the composition and size of workshops, the profile and level of their specialization, the duration of the production cycle, the coefficient of territory development, cost and profit. The main factors determining the type, complexity and hierarchy (i.e. the number of levels of the enterprise) of the organizational structure of the enterprise are: scale of production and sales volume; range of products; complexity and level of product unification; the degree of development of the region's infrastructure; international integration of the enterprise, etc. Depending on the factors considered, the type of organizational structure is selected, which involves methods for planning work for production units and monitoring their implementation. For a quantitative analysis of the structure of an enterprise, various indicators are used that characterize the volume of output, the relationship between main, auxiliary and service industries, the efficiency of the spatial location of the enterprise, the nature of the relationships between divisions, the degree of centralization of individual productions, etc. Analysis of these indicators allows us to determine ways to create a rational structure of the enterprise , which should ensure the maximum possibility of specialization of workshops and sections, continuity and direct flow of production, the absence of duplicating and overly fragmented divisions, the possibility of expanding and repurposing production without stopping it.

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Abstract on the topic “Production and technological processes in mechanical engineering” updated: July 31, 2017 by: Scientific Articles.Ru

MINISTRY OF EDUCATION AND SCIENCE OF THE RUSSIAN FEDERATION

NATIONAL NUCLEAR RESEARCH UNIVERSITY "MEPhI"

V. A. Ermolaev

TECHNOLOGICAL PROCESSES IN MECHANICAL ENGINEERING

For university students

Moscow 2011

UDC 669.018.29.004.14(075.8) BBK 34.5ya 73 E-74

Ermolaev V. A. TECHNOLOGICAL PROCESSES IN MECHANICAL ENGINEERING. Lecture notes. M.: National Research Nuclear University MEPhI, 2011. – 264 p.

Modern and promising technological methods for the production of ferrous and non-ferrous metals, the production of blanks and machine parts from metals and non-metallic materials are considered: casting, addition processing, welding, cutting and other methods.

The manual is intended for full-time, evening and part-time students in specialty 151001 – Mechanical Engineering Technology.

Prepared within the framework of the Program for the creation and development of National Research Nuclear University MEPhI.

Reviewer: V.S. Gatskov, Ph.D. tech. Sciences, Associate Professor NGTI

Editor E.N. Kochubey

The layout is prepared for printing by E.N. Kochubey

National Research Nuclear University "MEPhI". 115409, Moscow, Kashirskoe highway, 31.

LLC "Printing complex "Kurchatovsky". 144000, Moscow region, Elektrostal, st. Krasnaya, 42

Topic 1. TECHNOLOGICAL PROCESSES
IN MECHANICAL ENGINEERING PRODUCTION....................................
1.1. Concept of technology......................................................... ........................
1.2. Product as an object of production............................................................. ......
1.3. Processing of parts................................................... ...........................
Topic 2. MATERIALS USED
IN MECHANICAL ENGINEERING................................................... ...........................
2.1. Iron production................................................... .......................
2.2. Steel production........................................................ ........................
2.3. Production of non-ferrous metals................................................................... .....
Questions for self-control................................................................... ....................
Topic 3. FOUNDRY PRODUCTION.................................................... ....
3.1. Metal casting as a technological process....................................
3.2. Casting molds and their designs.................................................... ..
3.3. Receiving castings................................................... ...........................
3.4. Casting methods and areas of their application....................................................
Topic 4. PRESSURE TREATMENT OF METALS....................................
4.1. The essence of metal forming...................................................
4.2. Classification of metal processing processes
pressure and their brief characteristics...................................................
4.3. Rolling (rolling) of metals.................................................... ......
4.4. Metal pressing......................................................... ...................
4.5. Metal drawing............................................................. ......................
4.6. Forging of metals................................................... ...............................
4.7. Volumetric metal stamping...................................................... ......
4.8. Sheet (flat) stamping.................................................... ........
Self-test questions................................................................... ...................
Topic 5. CONCEPT OF POWDER TECHNOLOGY
METALLURGY................................................... ....................................
5.1. Powder metallurgy technology method....................................
5.2. Pressing metal powders....................................................
Questions for self-control................................................................... ...................
Topic 6. BASIC CONCEPTS ABOUT WELDING OF METALS......
6.1. General information. Development of welding, its directions
and classification................................................... ............................
6.2. Types of welded joints......................................................... .............
6.3. Preparing metal for welding.................................................... ......

6.4. Electric welding arc.................................................... ......
6.5. Metallurgical processes during welding....................................................
6.6. Electrodes for arc welding.................................................... .......
6.7. Equipment for metal welding....................................................
Questions for self-control................................................................... ...................
Topic 7. TYPES OF WELDING.................................................... ............................
7.1. Manual arc welding................................................................... ....................
7.2. Automatic and semi-automatic welding....................................
7.3. Gas welding................................................ ................................
7.4. Oxygen cutting................................................ ........................
Questions for self-control................................................................... ...................
Topic 8. MECHANICAL PROCESSING OF BLANKETS
CUTTING........................................................ ........................................................
8.1. Methods for processing workpieces by cutting....................................................
8.2. Processing of workpieces on CNC lathes....................................
Questions for self-control................................................................... ...................
Topic 9. ELECTROPHYSICAL, ELECTROCHEMICAL
AND THERMAL METHODS OF PROCESSING PARTS.................................
9.1. Characteristics of electrophysical
and electrochemical processing methods...................................................
9.2. Heat treatment in technological
product manufacturing process......................................................... .....
Questions for self-control................................................................... ...................
Topic 10. WEAR-RESISTANT AND ANTI-CORROSION
COATINGS........................................................ ...........................................
Questions for self-control................................................................... ...................
Topic 11. SOLDERED AND ADHESIVE JOINTS....................................
11.1. Soldering................................................. ............................................
11.2. Gluing................................................. ........................................
Questions for self-control................................................................... ...................
Topic 12. TECHNOLOGICAL TRAINING
PRODUCTS PRODUCTION................................................................. .............
12.1. Goals and objectives of technological training
production........................................................ ................................
12.2. Technological documentation................................................................ .
12.3. Methods for ensuring manufacturability
and competitiveness of mechanical engineering products...................
Questions for self-control................................................................... ...................
Literature................................................. ...............................................

Topic 1. TECHNOLOGICAL PROCESSES IN ENGINEERING PRODUCTION

The subject of the course “Technological processes in mechanical engineering production” (TPM) is modern rational and progressive methods of shaping blanks and machine parts, widespread in industry.

The TPM course occupies a special place in the development of a modern mechanical engineer, since subsequently the engineer must implement various machine designs in metal.

When creating the designs of machines and devices, ensuring in practice their specified characteristics and reliability of operation, taking into account economic indicators, the engineer must confidently master the methods of manufacturing machine parts and their assembly. To do this, he must have deep technological knowledge.

1.1. Concept of technology

Technological process defined as:

1) a set of production methods and processes in a particular industry, as well as a scientific description of the method

bov production(Ozhegov S.I. Explanatory Dictionary of the Russian Language);

2) a set of methods of manufacturing, processing, changing the properties, condition, form of raw materials, semi-finished products, materials carried out in the process of production(Vasyukov I.A. Dictionary of foreign words).

IN both definitions contain the keywords – production

natural, production , and this is quite logical, because The standard of living of people in modern society is determined by the efficiency of production!

The primary task of the domestic economy is to

increasing labor productivity and quality of manufactured products

duction This can be achieved based on highly efficient technologies.

The development and improvement of any production is currently associated with its automation, the creation of robotics

ical complexes, the widespread use of computer technology, and the use of CNC machines. All this forms the basis on which automated control systems are created, optimization of technological processes and processing modes, and the creation of flexible production systems become possible.

An important area of ​​scientific and technological progress is also the creation and widespread use of new structural materials. In production, ultra-pure, ultra-hard, heat-resistant, composite, powder, polymer and other materials are widely used, which make it possible to dramatically increase the technical level and reliability of equipment. For example, the Buran spacecraft is lined with a heat-resistant composite material, light and durable, withstanding t > 1000 ° C; The Kursk nuclear submarine has 200 mm thick hull walls made of titanium - a hard, durable and lightweight material; in the manufacturing industry, VOK - artificial diamonds are used.

1.2. Product as an object of production

Mechanical engineering products and their components. Product

V mechanical engineering refers to any item of production that is to be manufactured at an enterprise. The product can be a machine, its assembled elements, or even a separate part, depending on what is the product of the final stage of this production. For example, for an automobile plant the product is a car, for a carburetor plant it is a carburetor, for an automatic piston plant it is a piston.

A part is a product (an integral part of a product) made from a material that is homogeneous by name and brand without the use of assembly operations. A characteristic feature of the part is the absence of detachable and permanent connections. A part is the primary assembly element of each machine.

An assembly unit is a product whose components are to be connected. A characteristic feature of a component part of a product from a technological point of view is the ability to assemble it separately from other elements of the product. Component

V Depending on the design, it can consist of either separate

parts, or from components of higher orders and details. There are components of the first, second and higher orders. The first-order component is included directly in the component part of the product. It consists either of individual parts or of one or more second-order components and parts. The second-order component is included in the first-order component. It is divided into parts or into components of the third order and parts, etc., a component of the highest order is divided only into parts. The considered division of the product into its component parts is carried out according to technological characteristics.

There is another division when the product is divided into component parts according to functionality. These include, for example, the engine’s gas distribution mechanism, its lubrication or cooling system. These components of the product are not assembly parts from a technological point of view, since in most cases they cannot be separated and completely assembled separately from other elements of the product. The division of a product into its component parts and the preparation of drawings and other technical documents in mechanical engineering is given in GOST 2.101–68.

IN In modern mechanical engineering, the assembly is divided into a general

And nodal The object of the general assembly is the product, the object of the subassembly is its components.

Service purpose of the product. Under official appointment

These machines understand the clearly formulated specific task that the machine is designed to solve.

The formulation of the service purpose of the machine must contain detailed information specifying the general task and clarifying the conditions under which this task can be solved. Thus, when formulating the official purpose of a car, it is not enough to say that the car is intended to transport goods. It is necessary to specify the nature of the goods, their weight and volume, conditions, distances and speed of transportation, road conditions, climate, requirements for the appearance of the car and much more in order to comprehensively determine exactly the task that the car being created must perform.

The service purpose of a machine is described not only verbally, but also by a system of quantitative indicators that determine its specific functions, operating conditions and a number of additional points in accordance with the task to be solved using the machine being created. The formulation of the service purpose of the machine is the most important document in the task for its design.

Product quality indicators. Under the quality of the machine

take the totality of its properties that determine the ability to fulfill its official purpose. The quality indicators of a machine can only include that which characterizes the measure of the machine’s usefulness, i.e. its ability to meet people's needs in accordance with its purpose. Such indicators are the quality of products produced by the machine, machine productivity, its reliability, physical and moral durability, operational safety and ease of operation, noise level, efficiency, degree of mechanization and automation, technical aesthetics, etc.

Specific labor is invested in the design of the machine, its manufacture, operation, maintenance and repairs. The creation of a machine, its operation, maintenance and repairs involve the use of energy, technical means and materials. Everything taken together forms the cost property of the machine - its efficiency. An indicator of the efficiency of a machine can be the sum of costs for the design of Zpr, manufacturing of Zizg, operation of Ze, maintenance of Zt.o and repairs Zrem, related to the number N of products produced during its service period:

E = Z pr + Z bend + Z e + Z t.o + Z rep.

There are connections between the indicators of quality and efficiency of a machine, leading to the influence of one on the other. For example, improving the quality of a car by any indicator is associated with an increase in its cost. But at the same time, increasing the level of such a quality indicator as machine reliability will reduce the cost

waste of labor on troubleshooting, maintenance and repairs. The consumption of energy, fuel, and materials by a machine during operation, which to a certain extent characterizes the efficiency of the machine, largely depends on the quality of its manufacture, etc.

The presence of connections between indicators of quality and efficiency does not mean freedom to assign one or another indicator to any of the categories. The possibility of such freedom is excluded by the fundamental difference between indicators of quality and efficiency. The first of them reflect the degree of suitability, usefulness, and finally, the benefits that a person obtains using a machine, the second - the price of these benefits, their value.

The quality of a machine is ensured by the level of design solutions, on which the technical perfection of the machine’s design depends, and by technology, which determines the quality of parts, assembly and finishing of the machine (Fig. 1.1).

The profitability of a machine is more complexly dependent on the technical perfection of the machine’s design and its manufacturing technology. For example, the cost of a machine depends on the quality, quantity and cost of materials selected by the designer during the design process. However, the final costs of materials included in the cost can be determined only after the technological process of its manufacture has been completed.

The level of unification and manufacturability of the machine is determined by the designer. But the influence of these factors on the cost of the machine is not manifested directly, but through the technology of its manufacture. The influence of these same factors will also affect the costs of maintenance and repair of the machine. Economic indicators such as the machine’s consumption of energy, fuel and materials during operation primarily depend on the quality of design solutions. However, the values ​​of these indicators are influenced by the quality of the technological process implementation, etc.

Thus, ensuring the quality and efficiency of the machine during its creation is the common task of the designer and technologist. Its successful solution is possible with close cooperation and mutual understanding with each other.

Rice. 1.1. A set of properties that determine the quality and efficiency of a machine

Types of production and their features

There are different types of production: single, serial and mass. The type of production is determined by the breadth of the product range, regularity, stability and volume of product output.

One of the main characteristics of the type of production is transaction consolidation ratio– the ratio of the number of all technological operations performed or to be performed within a month to the number of jobs.

Single production characterized by a small volume of production of identical products, the re-production and repair of which, as a rule, is not provided for.

Mass production characterized by the manufacture or repair of products in periodically repeating batches.

Mass production characterized by a large volume of output of products that are continuously manufactured or repaired over a long period of time, during which one work operation is performed at most workplaces.

In mass production, special machines, fixtures, cutting and measuring tools are widely used; characterized by pronounced specialization, deep division of labor processes and a high degree of mechanization, continuity of production processes, short production cycle, high labor productivity and low cost of the product.

Depending on the type of production, it is dominated by either technological(single and small-scale production), or subject(mass and large-scale production) the principle of forming workshops.

Methods for performing technological processes

Technological process is part of the production process and contains actions to change and subsequently determine the state of the item of production. It is a set of mechanical, physical and chemical processes - operations during which the shape of parts into assembly units and the finished product is changed, and the compliance of the finished product with the drawing and technical specifications is checked.

Technological operation- a completed part of the technological process performed at one workplace.

The following methods are distinguished: processes:

1. Shaping– production of a workpiece or product from liquid, powder or fibrous materials. Types of shaping:

A) casting– shaping from liquid metal by filling it with a cavity of a given shape and size, followed by solidification;

b) molding– shaping from powdery or fibrous material by filling it with a cavity of a given shape and size, followed by compression;

V) electrotype–shaping from a liquid material by deposition of metal from a solution under the influence of an electric current.

2. Processing– a specified change in the shape, size, roughness or properties of a workpiece during a technological process. Types of processing:

A) cutting processing– processing, which consists in the formation of new surfaces by deformation and subsequent separation of the surface layers of the material with the formation of chips;

b) pressure treatment– consists of plastic deformation or separation of the workpiece material without the formation of chips, for example forging, stamping;

V) heat treatment– consists in changing the structure and properties of the workpiece material due to thermal influences;

G) electrical processing– consists of changing the shape, size and surface roughness of workpieces by using electrical discharges, magnetostriction effect, electronic or optical radiation, ion flows and plasma jets;

d) electrochemical processing– consists of a change in shape, size and roughness due to the dissolution of its material in an electrolyte under the influence of an electric current;

e) carrying a covering– processing consisting in the formation of a surface layer on a workpiece from a given foreign material, for example, painting, anodizing, oxidation, metallization, spraying, etc.

and) surfacing– fusion welding, during which a layer of metal of the required composition is applied to the surface of the part;

h) welding– welding performed to increase the size of a part or to impart certain properties to its surface is carried out both by fusion welding and pressure welding.

3. Assembly– formation of detachable or permanent connections of the component parts of the product or the product as a whole.

Process execution tools

Technological equipment– production tools in which, to perform a certain part of the technological process, materials or workpieces are placed, means of influencing them and, if necessary, energy sources, for example: foundry machines, presses, machine tools, welding equipment.

Technological equipment– production tools added to technological equipment to perform a certain part of the technological process, for example: cutting tools, dies, fixtures, gauges, molds, models.

Flexible Productivity System (FPS)– a set of various combinations of CNC equipment, robotic technological complexes, flexible production modules, individual units of technological equipment and systems for ensuring their functioning in automatic mode for a given time interval, which has the property of automated changeover in the production of products of an arbitrary nomenclature within the established limits of the values ​​of their characteristics .

The components of the GPS are:

1. Flexible Manufacturing Module (FMM)– a unit of technological equipment for the production of products of an arbitrary range within the established limits of their characteristics with program control, operating autonomously, automatically performing all functions associated with their production, and having the ability to be integrated into a flexible production system.

2. Robotic technological complex (RTC)– a set of units of technological equipment, a production robot and equipment that operates autonomously and carries out multiple cycles. RTKs intended for operation in GPS must have automated readjustment and the ability to be integrated into the system.

3. GPS functioning support system– a set of interconnected automated systems that provide design of products, technical preparation of their production, control of GPS using a computer and automatic movement of production items and technological equipment.

Development of a technological process taking into account ESTD

Designing the technological process for manufacturing parts, combining them into a finished product that strictly complies with the drawing and technical requirements, consists of developing the most rational and economical methods of work with the least amount of labor and money under specific production conditions.

Technological preparation is the most important stage in organizing production, during which the most rational methods for manufacturing products are determined, taking into account the planned scale and timing of production, and ensure the development of appropriate technological documentation.

For all parts included in the product, the order and content of operations are determined, equipment, cutting tools, measuring and control equipment, technological equipment, and technical standards are selected.

Typification of technological processes consists of classifying parts and their elements and comprehensively solving all problems that arise during the implementation of processes of each classification group. Work on typing technological processes consists of classification, development of the processes themselves and solving individual technological problems.

Class are called a set of parts characterized by a commonality of technological problems that can be solved under the conditions of a certain configuration of these parts. Within each class, parts are divided into groups, subgroups, and ultimately into types that are most similar to each other.

Type- this is a set of parts of the same class that, under the same conditions, have a general plan for processing the main surfaces, i.e. processed by basically the same methods (uniform equipment, fixtures and tools).

Typification of technological processes helps to accelerate and improve the design of technological processing processes, the introduction of the most appropriate options and advanced technological production methods.

Typification of technological processes is inextricably linked with standardization and unification of machines and technological equipment.

Effective for mass production group method of processing parts. All technologically similar parts, manufactured using the same type of equipment and tool attachments, are combined into classes and groups and a group technological process is created for each group.

Basic provisions of group technology:

1) the adopted sequence of technological operations ensures the processing of any part of the group;

2) technological equipment must be suitable for the manufacture of any part of the group;

3) the equipment provides high-performance processing with minimal costs for its readjustment.

The group processing method simplifies production preparation, reduces time, and improves the production organization system. In conditions of single and serial production, labor productivity is increased due to the use of highly progressive methods of processing and labor organization inherent in mass production.

Introduction

The set of methods and techniques for manufacturing machines, developed over a long period of time and used in a certain area of ​​production, constitutes the technology of this area. In this regard, concepts arose: casting technology, welding technology, machining technology, etc. All these areas of production relate to mechanical engineering technology, covering all stages of the process of manufacturing engineering products.

The discipline “Mechanical Engineering Technology” comprehensively studies the issues of interaction between a machine, fixture, cutting tool and workpiece, ways to construct the most rational technological processes for processing machine parts, including the choice of equipment and technological equipment, and methods for rationally constructing technological processes for assembling machines.

The doctrine of mechanical engineering technology in its development has passed in a few years from a simple systematization of production experience in mechanical processing of parts and assembly of machines to the creation of scientifically based provisions developed on the basis of theoretical research, scientifically conducted experiments and generalization of the best practices of machine-building plants. The development of machining and assembly technology and its direction are determined by the tasks facing the machine-building industry of improving technological processes, finding and studying new production methods, further developing and introducing comprehensive mechanization and automation of production processes based on the achievements of science and technology, ensuring the highest labor productivity with proper quality and lowest cost of manufactured products.

1. Production and technological processes

The production process is understood as the totality of all actions of people and tools carried out at an enterprise to obtain finished products from materials and semi-finished products.

The production process includes not only the main processes 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, manufacture of fixtures and tools, etc. .).

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

The technological process of machining parts must be designed and carried out in such a way that, through the most rational and economical processing methods, the requirements for parts are satisfied (processing accuracy, surface roughness, relative position of axes and surfaces, correctness of contours, etc.), ensuring the correct operation of the assembled cars.

2. Process structure

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, positions, transitions, moves, techniques.

Technological operation is a part of the 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 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 - at the other end, is one operation.

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

Installation refers to 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.

For example, turning a shaft while fastening it in the centers is the first setting; turning the shaft after turning it and securing it in the centers for processing the other end - the second setting. Each time the part is rotated by any angle, a new setup is created.

An installed and secured workpiece 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 called each individual position of the workpiece occupied by it relative to the machine while it is 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- a completed part of a technological operation, characterized by the constancy of the tool used, the surfaces formed by the processing, or the operating mode of the machine.

Auxiliary transition– 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 perform a 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.

Under the worker progress understand the part of the 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, a working stroke is understood as the continuous operation of a tool, for example, on a lathe, the removal of one layer of chips with a cutter is continuous, on a planer - the 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 or when rolling the surface with a smooth roller to compact it), the concept of a working stroke is also used, as when removing chips.

Auxiliary move– 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.

Under reception understand the completed action of the worker; usually the techniques are auxiliary actions, for example, installing 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, assembling two parts, pressing in mating 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 structure of an enterprise with technological specialization

3. Labor intensity of the technological operation

Time and costs for performing operations are the most important criteria characterizing its effectiveness under the conditions of a given product production program. The product production program is a list of manufactured products established for a given enterprise, indicating the production volume for each item for the planned period of time.

Production volume is the number of products, specific names, types of sizes and designs, manufactured during the planned period of time. The volume of output is largely determined by the principles of constructing the technological process. The calculated, maximum possible volume of product output per unit of time under certain conditions is called production capacity.

For a given output volume, products are manufactured in batches. This is the number of pieces of parts or a set of products simultaneously put into production. A production batch or part thereof that arrives at the workplace to perform a technological operation is called an operating batch.

A series is the total number of products to be manufactured according to unchanging drawings.

To perform each operation, a worker expends a certain amount of labor. The labor intensity of an operation is the amount of time spent by a worker of the required qualifications under normal labor intensity and conditions for performing this work. Units of measurement – ​​man/hour.

4. Standard time

Proper regulation of working time spent on processing parts, assembling and manufacturing the entire machine is of great importance for production.

Standard time is the time allotted for producing a unit of product or performing a certain job (in hours, minutes, seconds).

The time standard is determined on the basis of technical calculation and analysis, based on the conditions for the fullest possible use of the technical capabilities of equipment and tools in accordance with the requirements for processing a given part or assembling a product.