FEDERAL AGENCY FOR EDUCATION
STATE EDUCATIONAL INSTITUTION
HIGHER PROFESSIONAL EDUCATION
VOLGOGRAD STATE TECHNICAL UNIVERSITY
KAMYSHINSKY TECHNOLOGICAL INSTITUTE (BRANCH)
Department of Mechanical Engineering Technology
Technological processes in mechanical engineering
Guidelines
Volgograd
UDC 621.9(07)
Technological processes in mechanical engineering: guidelines. Part I / Comp. , ; Volgograd. state tech. un-t. - Volgograd, 2009. - 34 p.
The content of the discipline is stated, brief theoretical information on the topics of the course is given.
Designed for students of HPE specialty 151001 "Technology of Mechanical Engineering" part-time education.
Bibliography: 11 titles.
Reviewer: Ph.D.
Published by decision of the editorial and publishing council
Volgograd State Technical University
Ó Volgogradsky
state
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1.2. The tasks of studying the discipline
tasks study disciplines are:
§ study of the physical essence of the main technological processes for obtaining blanks;
§ study of the mechanical foundations of technological methods of shaping;
§ study of the possibilities, purpose, advantages and disadvantages of the main technological processes;
§ study of the principles and schemes of operation of the main technological equipment;
§ study of the designs of the main tools, fixtures and equipment.
1.3. Relationship with other curriculum disciplines
The study of the discipline "Technological processes in mechanical engineering" is based on the knowledge gained by students in the course of physics, mathematics, chemistry, engineering graphics, materials science.
In turn, this discipline ensures the successful study of the following disciplines: "Strength of materials", "Machine parts", "Engineering technology", "Fundamentals of machine-building production", "Shaping processes and tools", "Technological equipment" and "Equipment for machine-building production" .
2. CONTENT OF THE DISCIPLINE.
Topic 1. Introduction to technology.
1. Basic concepts and definitions.
2. Types of engineering industries.
3. The concept of the technological process.
4. The structure of the technological process.
1. Equipment and raw materials for metallurgical production.
2. Blast furnace iron production process.
3. Oxygen-converter steel production.
5. Steel production in electric furnaces.
1. Casting in sand-clay molds. Die casting. Investment casting. Centrifugal casting. Injection molding. Casting in shell molds.
2. Manufacture of castings in shell molds
3. Manufacture of castings by investment casting
4. Production of castings by mold casting
5. Production of castings by injection molding
6. Production of castings by casting under low pressure
7. Production of castings by centrifugal casting
8. Special casting methods.
1. Rolling and drawing.
2. Free forging and forging in backing dies. Hot and cold forging. Sheet stamping.
3. Heat treatment of forged and stamped forgings.
1. Welding by fusion, pressure and friction.
1. Physical basis of the cutting process.
2. Surface treatment of workpieces with a blade (turning, drilling, planing, milling, broaching) and abrasive tools (grinding, lapping, honing).
3. Laboratory practice.
4. topic 1. Introduction to technology.
Machine-building parts are made by casting, pressure treatment, cutting. Blanks are often obtained by pressure, casting or welding, the rational choice of blanks is due to the need to save metal.
One of the main technological processes of machine-building production is cutting. By cutting, high precision parts can be obtained. As a rule, it is impossible to create mechanisms and machines from parts that have not been machined. Casting was previously used to produce products from copper, bronze, then cast iron, and later steel and other alloys.
The main foundry processes are metal melting, mold making, metal pouring, knockout, casting processing and control.
Pressure treatment has also been used for a long time for the manufacture of weapons, in shipbuilding. Workpieces made of steel, non-ferrous metals and alloys, plastics are processed by pressure. Forming methods provide the production of complex shaped profiles with low roughness.
Welding processes were first carried out in Russia at the end of the 19th century. Welding is used to obtain permanent joints. Workpieces obtained by welding can then be processed by cutting.
In addition to these metal processing processes, more highly efficient technological processes have now been developed based on new physical phenomena that allow changing the shape and surface quality of parts. These are electrophysical and electrochemical processing methods that ensure the continuity of processes while simultaneously deforming the entire surface to be treated.
Production of products is divided into single, serial and mass.
Machine-building plants consist of separate production units and services - these are: 1) procurement workshops (iron foundries, steel foundries, forging, pressing, stamping); 2) processing shops (mechanical, prefabricated, painting); 3) auxiliary shops (tool, repair); 4) storage devices; 5) energy services; 6) transport services; 7) sanitary; 8) general factory institutions and services.
The process of creating a machine is divided into two stages: design and manufacture. The first stage ends with the development of the machine design and its presentation in the drawings. The second stage ends with the sale of the product in metal. Design is carried out in several stages: 1) design; 2) manufacturing of experimental parts and assemblies; 3) testing; 4) specification of technical solutions; 5) release of design documentation.
Manufacturing is divided into technical stages. preparation and production.
5. Topic 2. Fundamentals of metallurgical production of ferrous and non-ferrous metals.
5.1. Equipment and raw materials for metallurgical production.
Metallurgy is the science of methods for extracting metals and natural compounds and the branch of industry that produces metals and alloys.
Modern metallurgy - these are mines for the extraction of ores and coal, mining and processing plants, coking and energy enterprises, blast furnace shops, ferroalloy plants, steelmaking and rolling shops.
For the production of ferrous and non-ferrous metals, metal ores, fluxes, fuels and refractory materials are used.
Ore - a rock or mineral substance from which, at a given level of technological development, it is economically feasible to extract metals or their compounds. When studying the topic, pay attention to the types of ores used in the smelting of iron, their chemical composition and the percentage of metal produced,
In blast-furnace production, iron ore raw materials with an iron content of 63-07% are used. To obtain raw materials with a high iron content, the ores are pre-enriched. Considering the processes of ore beneficiation, pay attention to the agglomeration and rounding of iron ore concentrates.
Various fluxes are used to form fusible compounds (slags) of gangue ore and fuel ash. Familiarize yourself with the materials used as fluxes in the production of iron and steel. Pay attention to the choice of flux depending on the melting furnaces used (acidic or basic) and the ability to control the processes of removing harmful impurities from the melt.
Various types of fuel are used as a source of heat in the production of metals and alloys. When studying types of fuel, pay special attention to the main type of metallurgical fuel - coke. It is necessary to know the method of its production, chemical composition, properties and calorific value. From other types of fuel, pay attention to natural and blast-furnace gases, which are also widely used in metallurgy.
The processes of extracting metals in metallurgical units occur at high temperatures. Therefore, the inner lining (lining) of metallurgical furnaces and ladles for pouring metal is made of special refractory materials. When looking at refractory materials, pay attention to their chemical composition, refractoriness and applications.
5.2. Blast furnace iron production process.
Cast iron is smelted in shaft-type furnaces - blast furnaces. A modern blast furnace is a powerful high-performance unit. Familiarize yourself with the design of a blast furnace and the principle of its operation, as well as the design of air heaters and charge loading mechanisms. During the combustion of coke, heat is released in the blast furnace and a gas stream is formed containing CO, CO2 and other gases, which, rising up, give off heat to the charge materials. In this case, a number of transformations take place in the charge: moisture is removed, carbon dioxide compounds are decomposed, and when the charge is heated to a temperature of 570°C, the process of reduction of iron oxides begins. Therefore, considering the processes of blast furnace smelting, study the chemical reactions of fuel combustion, the processes of reduction of oxides of iron, silicon, manganese, phosphorus and sulfur, the processes of formation of cast iron (carburization of iron) and slag. In addition, pay attention to the release of pig iron and slag from a blast furnace, as well as products of blast furnace smelting: pig iron, foundry iron, ferroalloys, slag and blast furnace gas. Consider the areas of use of these products in the national economy,
* The most important technical and economic indicators of blast-furnace production are the utilization factor of the useful volume of the blast-furnace (KIPO) and the specific consumption of coke. You should know how to determine the KIPO of a blast furnace, and have an idea of its value at the leading metallurgical enterprises of the country, as well as the coke consumption coefficient per 1 ton of smelted iron. Pay special attention to questions of mechanization and automation of the operation of the blast furnace and ways to intensify the blast furnace process.
5.3. Oxygen-converter steel production.
The main raw materials for steel production are pig iron and steel scrap. The process of obtaining steel is based on the oxidation of impurities. Therefore, when studying the topic, pay attention to the selective oxidation of impurities and their transfer to slag and gases during the smelting process in various melting units; open-hearth furnaces, oxygen converters, electric arc furnaces, etc.
One of the progressive methods of steel production is the oxygen-converter method, which produces about 40% of this steel. The oxygen-converter process is characterized by high productivity, relatively low capital costs and ease of automating the control of the melting process. Carbon and low-alloy steels are smelted in oxygen converters. When studying the oxygen-converter steel production, familiarize yourself with the design of modern oxygen converters and the principle of their operation. Consider the charge materials of converter production and smelting technology, paying attention to the oxidation period of smelting and steel deoxidation. Make a comparative assessment of the work of open-hearth furnaces and oxygen-converter production.
In open-hearth furnaces, carbon structural, tool and alloy steels are smelted. Familiarize yourself with the device of modern open-hearth furnaces and the principle of their operation. Consider in detail the process of steel production in the main open-hearth furnaces. Pay special attention to the production of steel by the scrap-ore process as the most economical. Study the characteristic melting periods of this process and their significance. In conclusion, consider the features of the steel melting process in acid open-hearth furnaces and ways to intensify the open-hearth process.
5.5. Steel production in electric furnaces.
High-quality, tool and high-alloy steels are smelted in electric arc and induction furnaces. They can quickly heat, melt and accurately control the temperature of the metal, create an oxidizing, reducing and neutral atmosphere or vacuum. In addition, metal can be more completely deoxidized in these furnaces. Studying the production of steel and an electric arc furnace, familiarize yourself with its structure and principle of operation. Considering the process of melting in an arc furnace, pay attention to the fact that two melting technologies are used in such a furnace: remelting - on a charge from alloyed wastes and oxidation of impurities on a carbonaceous charge. It is necessary to learn the features of both processes and to know their technical and economic indicators.
Studying the production of steel in induction electric furnaces, familiarize yourself with their design and principle of operation. Please note that in induction furnaces, steel is obtained by remelting or melting charge materials. It is necessary to understand the features of these processes.
Compare the technical and economic indicators of various methods of obtaining steel.
6. Topic 3. Fundamentals of technology for the production of castings from ferrous and non-ferrous metals.
6.1. Casting in sand-clay molds. Die casting. Investment casting. Centrifugal casting. Injection molding. Casting in shell molds.
The main products of the foundry are complex (shaped) workpieces, called castings. Castings are obtained by pouring molten metal into a special casting mold, the internal working cavity of which has the shape of a casting. After solidification and cooling, the casting is removed by destroying the mold (single mold) or taking it apart (multiple mold).
Castings are obtained by various casting methods, which, having the same essence, differ in the material used for the mold, the manufacturing technology, the conditions for pouring the metal and forming the casting (pouring free, under pressure, crystallization under the action of centrifugal forces, etc.) and other technological features. The choice of casting manufacturing method is determined by its technological capabilities and economy.
About 80% of castings are made by the most versatile, but less accurate method - sand casting. Special casting methods produce castings of increased accuracy and surface finish with a minimum amount of subsequent machining.
Describing foundry production as a whole, one should single out the main advantage that distinguishes it favorably from other methods of billet shaping - this is the possibility of obtaining blanks of almost any complexity of various weights directly from liquid metal.
The bulk of the castings are made from cast iron (72%) and steel (23%).
6.2. Casting in sand-clay molds.
Start your study of the topic by considering the sequence of making a casting in a sand mold. For the manufacture of a sand mold, a model kit, flask equipment and molding materials are used.
The model kit includes a casting model (model plates), core boxes (if the casting is made using cores), models of the gating-feeding system. It is necessary to master the basics of designing model kits well. For example, the model corresponds in configuration to the external configuration of the casting and the iconic parts of the rods.
The design of the model must provide the possibility of compacting the molding sand and removing the model from the mold. Therefore, the model is most often made detachable, molding slopes are provided on the vertical walls, and fillets are provided at the transition points of the walls. The dimensions of the model are performed taking into account the allowances for machining and linear shrinkage of the casting alloy.
Model kits are made of wood and metals (most often aluminum alloys and cast iron). Explore examples of model designs, pattern plates, and core boxes. Pay attention to the cases in which it is more expedient to use wooden model kits, and in which metal ones.
When studying molding and core sands, pay attention to their thermophysical, mechanical and technological properties, as they largely affect the quality of castings. Consider facing, filler, and uniform sands, as well as fast-setting and self-hardening sands. Pay attention to the difference in the composition of the molding sands for steel, cast iron and non-ferrous alloys.
Increased requirements are imposed on core mixtures, since the core is in more difficult conditions than the mold. Consider mixtures that harden in contact with the corebox when hot and cold.
Molds and cores are made by hand and by machines. Learn how to make molds by hand in paired flasks, from a template, making large molds in caissons, and various machine molding methods. Consider the schemes for compacting the mixture by pressing, shaking and sand thrower. Pay attention to ways to improve the quality of compaction by diaphragm and differential pressing with a multi-plunger head, as well as additional pressing when compacting molds by shaking.
Disassemble the methods of making rods manually and on machines. Pay attention to technological measures to ensure higher requirements for them (the use of frames, ventilation ducts, etc.). Progressive process is the production of rods on hot boxes. A sand-resin mixture is blown into a metal box heated to 250–280°C.
Under the action of heat, the resin melts, envelops the grains of sand, and when cooled, the resin solidifies. The result is a rod with high strength.
The labor-intensive operation of compacting the mixture is greatly simplified when using liquid self-hardening mixtures (LSS), which are poured into flasks and core boxes, and after 30-60 minutes the molds and cores acquire the necessary strength. When stored in air, their strength increases. The high plasticity of the mixtures and their hardening in contact with the model ensure the production of castings with higher dimensional accuracy. Molds and rods made of LSS have good gas permeability and easy knockout.
A new technological process is the manufacture of castings according to gasified models, which are made of expanded polystyrene and are not removed from the mold, but are gasified when the mold is poured with metal.
The pouring of the assembled molds is carried out on conveyors, where they are cooled to the “knockout” temperature. Knockout of castings from molds and cores from castings is carried out on vibrating gratings. Particular attention should be paid to the issues of mechanization of labor-intensive operations and to understand the principles of operation of automated molding and pouring conveyors, production lines for the manufacture of castings, knockout of molds and further cooling of castings to normal temperatures.
6.3. Manufacture of castings in shell molds.
The essence of the process lies in the free pouring of molten metal into molds made from a special mixture with thermosetting binders by hot molding. Studying this topic, consider the scheme of the shell formation process, the sequence of operations for making shells by the bunker method, assembling the molds and preparing them for pouring with molten metal. Pay attention to the composition and properties of the molding sand and the features of the foundry equipment used in the manufacture of molds and cores.
Note the main advantages of making castings in shell molds; high accuracy of geometric dimensions of castings, low surface roughness of castings, reduction in the amount of molding materials, saving production space, facilitating knockout and cleaning of castings, the possibility of full automation of the production process through the use of multi-position rotary automatic machines and automatic lines. Along with the advantages, consider the disadvantages of the method: the high cost of thermosetting binders and the use of heated casting equipment. In addition, pay attention to the technological possibilities of the method and the scope of castings,
6.4. Production of castings by investment casting. The essence of the process lies in the free pouring of molten metal into molds made from a special refractory mixture according to one-time models, which are melted, burned out or dissolved after the mold is made. Studying the topic, consider the sequence of making models from a low-melting composition in molds, assembling models into a block, making a mold, preparing it for pouring, pouring molten metal, knocking out and cleaning castings. Pay attention to the following features of this method: a one-time model made from a fusible model composition does not have a connector and iconic parts, and its contours follow the shape of the casting; the form obtained from investment models is a thin-walled shell that does not have a split; the mold is made from a special refractory mixture consisting of powdered quartz and hydrolyzed ethyl silicate solution; to ensure high strength and remove residues of the model composition, casting molds are calcined at a temperature of 850–900 ° C, after which they are poured with molten metal. In addition, note the main advantages of investment casting, paying attention to the fact that this method is the most economical way to produce small, but complex and responsible castings with high requirements for geometrical accuracy and surface roughness, as well as parts from special alloys. low casting alloys. Consider also the disadvantages of the method. Pay attention to technological opportunities and areas. application of the method.
6.5. Manufacture of castings by mold casting.
The essence of the process lies in the free pouring of molten metal into metal molds - molds. Consider the types of molds, the sequence of castings and the features of castings.
Considering the sequence of manufacturing castings, pay attention to the purpose of preheating the molds, heat-shielding coatings applied to the working surfaces of the molds, to the sequence of mold assembly. Metal rods are widely used to obtain internal cavities of castings.
When studying the features of casting in chill molds, pay attention to the increased rates of solidification and cooling of castings, which in some cases contributes to obtaining a fine-grained structure and an increase in mechanical properties, and in other cases causes rejection.
Considering the designs of molds, pay attention to the arrangement of channels for venting gases from the mold cavities and these devices used to remove castings, as well as to the design of metal rods.
For the manufacture of castings by mold casting, single-station and multi-station chill machines and automatic lines are widely used. Consider the principle of operation of a single-station chill machine,
Note the main advantages of mold casting: high accuracy of geometric dimensions, and low surface roughness of castings, improving the mechanical properties of castings, increasing productivity, saving production space, etc. Pay attention to the disadvantages of the method: the complexity of manufacturing molds and their low durability.
Understand the technological possibilities of the method and its scope.
6.6. Castingsinjection molding.
The essence of the process is the pouring of molten metal and the formation of a casting under pressure.
Studying the topic, consider the design of a horizontal cold chamber injection molding machine and the sequence of operations for making castings, the design of molds and devices for removing castings,
When studying the features of injection molding, pay attention to the fact that the molten metal inlet speed into the mold is 0.5-120m/s, and the final pressure can be 100MPa; consequently, the form is filled in tenths, and for especially thin-walled castings - in hundredths of a second. The combination of the features of the process - a metal mold and external pressure on the metal - makes it possible to obtain high quality castings.
Note the main advantages of injection molding: high accuracy of geometric dimensions and low surface roughness of castings, the possibility of manufacturing complex, thin-walled castings from aluminum, magnesium and other alloys, high productivity of the method. Pay attention also to the disadvantages of the method: the complexity of manufacturing molds, their limited service life. Pay attention to the technological possibilities of the method and its scope.
6.7. Production of castings by casting under low pressure.
The essence of the process is the pouring of molten metal and the formation of a casting under a pressure of 0.8 MPa. Studying the topic, consider the device of the low-pressure casting machine and the sequence of operations for making castings. Please note that the method allows you to automate mold casting operations, creates excess pressure on the metal during crystallization, which helps to increase the density of castings and reduce the flow of molten metal to the gating system. The disadvantage of this method is the low resistance of the metal wire, which makes it difficult to use low-pressure casting to obtain castings from iron and steel. Pay attention to the features of the design of castings, as well as to the technological capabilities and areas of its application.
6.8. Production of castings by centrifugal casting.
The essence of the process lies in the free pouring of molten metal into a rotating mold, the formation of a casting in which is carried out under the action of centrifugal forces. Studying the topic, consider the design of machines with horizontal and vertical axes of rotation and the sequence of operations for making castings. Pay attention to the advantages of centrifugal casting, the technological possibilities of the method and the scope. Along with the advantages, pay attention to the disadvantages of centrifugal casting.
6.9. Special casting methods.
Specialized casting methods include: continuous casting, vacuum suction casting, squeeze casting, liquid stamping, etc. Studying these topics, pay attention to the essence of the methods, process diagrams and technological sequence of operations. Consider the advantages and disadvantages, technological possibilities and applications of specialized casting methods.
7. Topic 4. Fundamentals of metal forming technology.
7.1. Rolling and drawing
Pressure treatment occupies a very large place in the modern metalworking industry. Over 90% of steel being produced and 60% of non-ferrous metals and alloys are subjected to pressure treatment. At the same time, products of various purposes, mass, and complexity are obtained, and not only in the form of intermediate blanks for final processing by cutting, but also finished parts with high accuracy and low roughness. Pressure treatment processes are very diverse and are usually divided into six main types: rolling , pressing, drawing, forging and sheet stamping. When studying these types, special attention should be paid to their technological capabilities and applications in mechanical engineering. In general, the use of pressure treatment processes is determined by the possibility of forming products with high productivity and low waste, as well as the possibility of improving the mechanical properties of the metal as a result of plastic deformation.
Rolling is one of the most common types of metal forming. During rolling, the metal is deformed in a hot or cold state by rotating rolls, the configuration and relative position of which may be different. There are three rolling schemes: longitudinal, transverse and transverse helical.
During the most common longitudinal rolling in the deformation zone, the metal is compressed in height, broadened, and stretched. The amount of deformation per pass is limited by the condition of metal capture by the rolls, which is ensured by the presence of friction between the rolls and the rolled workpiece.
Rolling tool - smooth and calibrated rolls; equipment - rolling mills, the device of which is determined by the products rolled on them.
The initial workpiece during rolling are ingots.
Rolled products (rolled products) are usually divided into four main groups. The largest share falls on the group of sheet products. The group of long products consists of profiles of simple and complex - shaped shapes. Rolled pipes are divided into seamless and welded. Special types of rolled products include rolled products, the cross section of which periodically changes along the length, as well as finished products (wheels, rings, etc.).
Rolled products are used as blanks in forging and stamping production, in the manufacture of parts by machining and in the creation of welded structures. Therefore, the assortment of the main groups of rolled products should be given special attention.
To obtain from rolled profiles of small sizes (up to thousandths of a millimeter), with high accuracy and low roughness, drawing is used, which is usually carried out in a cold state. Considering the scheme of metal deformation during drawing, it should be noted that in the deformation zone the metal experiences significant tensile stresses, the greater, the greater the drawing amplification. To prevent this force from exceeding the permissible value, leading to breakage of the product, the reductions in one pass are limited, measures are taken to reduce friction between the metal and the tool, and intermediate annealing is introduced, since the metal is strengthened during cold drawing.
The pressing process, carried out in a hot or cold state, makes it possible to obtain profiles of a more complex shape than during rolling, and with higher accuracy. Billets are ingots, as well as rolled products.
Consider the scheme of metal deformation during pressing, it should be noted that in the deformation zone the metal is in a state of all-round uneven compression. This feature makes it possible to extrude metals and alloys with reduced ductility, which is one of the advantages of this process. Pressing is more economical to produce small batches. profiles, since the transition from the manufacture of one profile to another is easier than with rolling. However, during pressing, tool wear is significant and metal waste is large,
Pressing is carried out on specialized hydraulic presses. Getting acquainted with the device of the tool, pay attention to the location and interaction of its parts when pressing solid and hollow profiles.
7.2. Free forging and forging in backing dies. Hot and cold forging. Sheet stamping.
Forging is used to obtain a small number of identical blanks and is the only possible way to obtain massive forgings (up to 250 tons).
The forging process, carried out only in a hot state, consists of alternating in a certain sequence the main forging operations. Before proceeding to the consideration of the sequence of manufacturing forgings, it is necessary to study the main forging operations, their features and purpose. The development of the forging process begins with drawing up a drawing of the forging according to the drawing of the finished part. Forging produces forgings of relatively simple shape, requiring significant machining. Allowances and tolerances for all dimensions, as well as laps (simplifying the configuration of the forging) are assigned in accordance with GOST 7062-67 (for steel forgings made on presses) or GOST 7829-70 (for steel forgings made on hammers).
As an initial billet during forging, rolled bars and blooms are used for small and medium-sized forgings; for large forgings - ingots. The mass of the workpiece is determined based on its volume, which is calculated as the sum of the volumes of forging and waste according to the formulas given in the reference literature.
The cross section of the workpiece is chosen taking into account the provision of the necessary forging, which shows how many times the cross section of the workpiece has changed during the digging process. The larger the forging, the better the metal is forged, the higher its mechanical properties.
The sequence of forging operations is set depending on the configuration of the forging and the technical requirements for it, on the type of workpiece.
With a variety of universal blacksmith tools used to perform basic forging operations, you need to familiarize yourself with the study of these operations. When studying the fundamental structure of splitting machines (pneumatic and steam-air hammers, hydraulic press), please note that the use of one or another type of equipment is determined by the mass of the forging.
As a result of studying the forging process, it is necessary to have a clear understanding of the requirements for the design of parts obtained from forged forgings.
7.3. Hot forging.
In forging, the plastic flow of metal is limited by the cavity of a special tool - a stamp, which serves to obtain a forging of only this configuration. Compared to forging, hot forging allows forgings to be produced that are very close in configuration to the finished part, with greater accuracy and high productivity. However, the need to use a special expensive tool for each forging makes stamping profitable only with sufficiently large batches of forgings. Forgings with a weight of up to 100–200 kg, and in some cases up to 3 tons are obtained by stamping. stamping of forgings of a more or less complex configuration, it is necessary to obtain a shaped blank, that is, to bring its shape closer to the shape of the forging. To this end, the original workpiece is usually pre-deformed in the procurement streams of multi-strand dies, in forging rolls, or in other ways. When stamping large batches of forgings, rolling of a periodic profile is used.
The presence of a wide variety of shapes and sizes of forgings, alloys from which they are stamped, has led to the emergence of various methods of hot forging. When classifying these methods, the type of stamp is taken as the main feature, which determines the nature of the deformation of the metal during the stamping process. Depending on the type of stamp, open die stamping and closed die stamping (or flashless stamping) are distinguished. Studying these stamping methods, you need to pay attention to their advantages, disadvantages and areas of rational use,
For stamping in open dies, the formation of a burr in the gap between the parts of the stamp is characteristic. When deformed, the burr closes the exit from die cavities for the bulk of the metal; at the same time, at the final moment of deformation, excess metal is displaced into the burr,
When stamping in closed dies, their cavity remains closed in the process of metal deformation. A significant advantage of the method is a significant reduction in metal consumption, since there is no waste in the burr. But the difficulty of using stamping in closed dies lies in the need to strictly observe the equality of the volumes of the billet and forging.
In addition to the difference in the type of die tool, stamping is distinguished by the type of equipment on which it is produced. Hot forging is carried out on steam-air hammers, on crank hot forging presses, horizontal forging machines, and hydraulic presses. Stamping on each of these machines has its own characteristics, advantages and disadvantages, which must be clearly understood. Having considered the schemes of forging machines and the principles of their operation, it is necessary to understand for which type of parts it is most rational to use this or that equipment, taking into account its technological capabilities. Much attention should be paid to the design features of forgings stamped on each type of machine.
The development of the forging process, just as in forging, begins with the drawing up of a forging drawing according to the drawing of the finished part, taking into account the type of equipment on which the forging will be performed. In this case, the correct choice of the location of the die parting plane is of great importance. Allowances, tolerances, laps, stamping slopes, curvature radii and sizes of bastings for firmware in accordance with GOST 7505–74 (for steel forgings) are set on the forging obtained by stamping.
The mass of the workpiece for stamping is determined based on the law of volume constancy during plastic deformation, counting the volume of the forging and the volume of technological waste according to the formulas given in the reference literature. The dimensions of the workpiece and the shape of its cross section are determined depending on the shape of the forging and the method of its stamping.
After stamping, the forgings are subjected to finishing operations, which are the final part of the hot forging process and contribute to the production of forgings with the required mechanical properties, accuracy and surface roughness. The complexity of subsequent machining depends on these operations.
7.4. Cold stamping.
Cold stamping is divided into three-dimensional and sheet. In case of volumetric stamping - cold extrusion, upsetting and molding - rolled steel is used as a blank. At the same time, products with high precision and surface quality are obtained. However, due to the fact that the specific forces in cold forging are much greater than in hot forging, its capabilities are limited due to insufficient tool life,
Sheet stamping includes the processes of deformation of blanks in the form of sheets, canvases, tapes and pipes,
Sheet stamping processes can be divided into operations, the alternate use of which allows you to give the original workpiece the shape and dimensions of the part. All sheet stamping operations can be combined into two groups: separating and shaping. When performing separating operations, the workpiece is deformed up to its destruction. When performing shape-changing operations, on the contrary, they strive to create conditions under which the greatest shape change of the workpiece can be obtained without its destruction.
When studying separating operations, pay attention to how the technological parameters of the process (for example, the size of the gap between the cutting edges) affect the quality of the resulting products. Of great importance in the development of processes for punching out products is the correct location of the cut-out parts on the sheet blank (material cutting). Proper cutting should provide minimal waste during cutting and a sufficient size of the jumpers between the parts, since the quality of the parts obtained depends on their size. The main indicator of cutting efficiency can be taken as the metal utilization factor, which is equal to the ratio of the area of the parts to the area of the sheet, strip or tape from which these parts are cut. At the same time, it should be noted that cutting parts from a rolled strip or tape is more economical.
Considering shape-changing operations, pay attention to the fact that during bending and drawing operations without specifying the wall, there is practically no change in the thickness of the workpiece.
During bending, compressive and tensile stresses simultaneously act in each section along the thickness of the workpiece, as a result of which the elastic deformation can be relatively large. Therefore, when bending, it is necessary to take into account the angle at which the product “springs”. The value of the springback angles for each specific case is found from reference books.
The magnitude of tensile stresses in a bent workpiece depends on the ratio R/5 (R is the bending radius, 5 is the thickness of the material) and may exceed the allowable value if the relative radius is too small. Reference literature gives minimum bending radii for various materials.
When drawing hollow products from a flat workpiece, the bottom of the product, located under the punch, is practically not deformed, and the rest of the workpiece (flange) is stretched in the radial direction and compressed in the tangential direction. Wrinkling sometimes occurs when the flange is compressed; to prevent this phenomenon, it is necessary to press the flange against the end of the matrix.
The force acting from the side of the punch on the workpiece increases with an increase in the ratio of the workpiece diameter to the diameter of the drawn product and can reach a value exceeding the strength of the wall of the drawn product. In this case, the bottom breaks off.
Sheet metal stamping tools - stamps - are very diverse. Rigid dies, usually used for sheet metal stamping, consist of working elements (punch and die) and a number of auxiliary parts. Such stamps are divided into simple (for performing one operation) and complex (for performing several operations).
Sheet punching equipment - mechanical presses of various designs.
In the manufacture of small batches of products, when the manufacture of complex dies is uneconomical, simplified methods of pressure treatment of sheet blanks are used: stamping with elastic media, spinning and pulse stamping,
When stamping with an elastic medium (for example, rubber), only one of the two working elements is made of metal, the role of the other is played by an elastic medium. Hydraulic and mechanical presses, as well as hammers, are used as equipment.
Spinning works are designed to obtain parts in the form of bodies of revolution and are performed on turning and spinning machines.
When pressless stamping with a liquid, gaseous medium or a magnetic field, special installations are used in which the energy necessary for deformation is obtained due to an electric discharge in a liquid, an explosion of an explosive or combustible mixtures, a powerful electromagnetic pulse. In these cases, the load of the workpiece is short-term (impulse ) character. This makes it possible to stamp complex parts from hard-to-form alloys, the stamping of which is difficult under normal conditions,
Studying the schematic diagrams of these types of stamping, pay attention to their advantages and disadvantages.
7.5. Heat treatment of forged and stamped forgings.
Heating of metal before plastic deformation is one of the most important auxiliary processes in pressure treatment and is carried out in order to increase plasticity and reduce deformation resistance. Any metal or alloy must be processed by pressure in a well-defined temperature range. For example, steel 10 can be subjected to hot deformation at temperatures not higher than 1260 ° C and not lower than 800 ° C. Violation of the temperature treatment interval leads to negative phenomena occurring in the metal (overheating, burnout) and ultimately to marriage. During heating, it is necessary to ensure a uniform temperature over the cross section of the workpiece and minimal oxidation of its surface. For the quality of the metal, the heating rate is of great importance: with slow heating, productivity decreases and oxidation (scale formation) increases, with too fast heating, cracks may appear in the workpiece. The tendency to form cracks is the greater, the larger the workpiece and the lower the thermal conductivity of the metal (high-alloy steels, for example, have lower thermal conductivity than carbon steels and have a lower heating rate).
Getting acquainted with the principle of operation and design of furnaces and electric heating devices, pay attention to their technological capabilities and scope, which is characterized by the size and size of the batch of blanks.
8. Topic 5. Fundamentals of technology for the production of welded products.
8.1. Welding by fusion, pressure and friction.
The study of the section should begin with a consideration of the physical essence of welding, for understanding which it is necessary to use information about the structure of the metal and the metallic bond between the atoms of the substance.
The metal consists of many positively charged ions, arranged in space and connected into a single cloud of collectivized electrons. When two metallic bodies come into contact, they usually do not combine into a single whole; this is prevented by irregularities on the surface and films of oxides, hydrides and nitrides that deactivate it. If the surfaces of the workpieces are activated and the weight of the surface ions is brought together at a distance of 2-3A (the ions are located in the solid metal at such a distance), then welding occurs, i.e., the permanent connection of the workpieces due to the implementation of interatomic bonding forces. In practice, this is achieved by thermal or force effects, or a combination of both.
In fusion welding, only thermal action takes place - heating to melt the edges of the workpieces with the formation of a single liquid metal pool. Its crystallization occurs by successive single or group settling of atoms of the liquid phase in the cavities of the crystalline one. lattice of the solid phase, in which interatomic bonds are established. As a result of crystallization in the welding zone, grains are formed that belong to both the base metal and the weld metal. The same atomic-crystalline structure of the metal is established in the welding zone.
Attention should be paid to the principle of choosing the type and brand of electrode for welding, as well as its diameter and the permissible welding mode. It is important to understand that the current in manual arc welding is supplied to one end of the electrode rod, and the arc burns at the opposite; the distance between them reaches 300–400 mm. With excessive current, overheating of the upper part of the electrode with Joule heat occurs, which causes peeling of the coating and marriage during welding. To prevent overheating, the electrode diameter is selected depending on the thickness of the metal being welded, and the welding current strength is selected according to the diameter of the electrode. The areas of application of this welding method (materials, thicknesses, types of structures) should be studied. It is effective for welding short, intermittent seams with a complex trajectory, and hard-to-reach places, in various spatial positions in conditions of repair, pilot production, installation and construction. In manual welding, the volume of liquid metal in the weld pool is insignificant, so that it can be held on a vertical wall or in a ceiling position due to surface tension forces. The disadvantages of the method include heavy manual labor and low productivity, which prevent its use and mass production.
When studying this process, it is important to understand how the process is started, maintained at specified conditions, protected from oxidation, and the role of the welder. The adjuster adjusts the machine for a given metal thickness by determining the required current strength, welding speed and arc voltage, and sets the electrode wire feed speed equal to the melting speed se in a given mode. Random mode deviations (slip of the feed rollers) are eliminated automatically according to two options , In machines with adjustable wire feed speed, depending on the voltage on the arc, the actions of the welder are counted. The machine continuously compares the set voltage and electrode feed rate. Simpler machines with a constant wire feed speed are based on self-regulation of the arc, due to which, with an accidental increase in the length of the arc, the welding current decreases. This reduces the melting rate of the electrode until the original mode is restored. It should be noted that self-regulation of the arc is effective for high current density (high current or small electrode diameter). The quality of the automatic welding process is ensured by the correct choice of wire grades for welding (they have a low content of impurities and are indicated by the index “Sv”), as well as flux. General requirements for flux; when interacting with the metal, it should give a slag with a density lower than that of the metal, which does not form intermediate compounds with it, and with greater shrinkage. This eliminates slag inclusions in the seam and achieves spontaneous separation of the slag crust from the seam during cooling.
It is necessary to study the features of the welding technology, having understood that in automatic welding the current conductor is close to the arc and it is possible to use high currents (up to 1600 A) without fear of overheating of the electrode and thereby achieve maximum productivity, but the large mass of the liquid pool allows welding only in lower position, and when welding the root weld, measures are required to keep the liquid pool (linings, flux pads). It is necessary to understand that it is rational to use automatic submerged arc welding to obtain the same type of units with extended straight and circumferential seams - for sheet blanks of increased thickness (more than 3 mm) from various steels, copper, nickel, titanium, aluminum and their alloys.
8.2. Plasma processing of metals.
It is necessary to understand that the source of heat is a jet of gas ionized in an arc, which, when colliding with a less heated body, deionizes with the release of a large amount of heat, which makes it possible to consider it an independent source. The plasma jet temperature depends on the degree of gas ionization. For this, a compressed arc column is used, that is, an arc burning in a narrow channel through which gas (argon, nitrogen, hydrogen, etc.) is blown under pressure, increasing the degree of its compression. Under these conditions, the gas temperature in the arc column reaches ° C, which, compared with a freely burning arc, sharply increases the degree of ionization and the temperature of the gas leaving the channel at high speed in the form of a jet. This heat source has high temperature, concentration and protective properties. The plasma jet is used in two ways: in combination with another (mainly in thermal cutting) and separately from the arc (in welding, surfacing and spraying). The latter option is also suitable for processing non-conductive materials.
8.3. Electron beam welding.
The process belongs to fusion welding, but unlike arc welding methods, it is carried out in a high vacuum, where there are few ions that carry electrical charges. For this reason, in a vacuum, an electric arc discharge is unstable. For vacuum welding with pressure
105–10b mm Hg Art. a stream of accelerated electrons is used as a heat source. The speed of electrons is approximately half the speed of light, which is achieved by a high voltage (40–150 kV) between the cathode and the workpiece (anode). Electrons emitted from the cathode are accelerated, concentrated into a beam and bombard the metal, releasing heat during deceleration due to the transition of kinetic energy into thermal energy. It is important to note that the beam energy can be concentrated on a very small area in the depth of the metal, where the deceleration of the main number of electrons occurs. This provides a very high penetration ability of the beam, which makes it possible to weld workpieces 50 mm thick in one pass without cutting edges and obtain seams of minimum width, which eliminates distortion of the workpiece shape during welding. Electron beam welding is applicable to workpieces placed in a chamber and provides the highest quality joints of any metals, including refractory ones that are easily oxidized at elevated temperatures.
8.4. Gas welding and cutting of metals.
During gas welding, the metal is melted by the heat released during the combustion of combustible gas mixed with oxygen. It is important that the highest temperature (3200 ° C) flame zone has reducing properties and protects the metal from oxidation during welding. Fluxes in the form of pastes are used to combat oxides on the surface of the metal to be welded. However, the effectiveness of these measures is insufficient when welding complexly alloyed alloys, as well as titanium alloys, etc. In addition, gas welding is not very productive and is not automated. For these reasons, its value is retained only when repairing cast iron, brass, thin-walled steel blanks and in the field in the absence of electricity,
In contrast to gas welding, the use of gas cutting in the industry is constantly expanding. It is important to understand that cutting is understood as welding and its power should depend on the size and shape of the workpieces, as well as on the thermal conductivity and electrical resistance of the material.
8.5. Friction welding and gas pressure welding.
It is important to understand that these methods are related to pressure welding, but differ in heat sources. It is necessary to consider their advantages in comparison with flash butt welding, process features and rational areas of application. It is important to keep in mind that for friction welding, one of the workpieces must have an axis of rotation.
The positive side of gas-pressure welding is a smoother heating and cooling mode than in resistance welding; it is suitable for welding particularly large workpieces. It is important that this does not require electricity, which allows it to be used for repair and other work in the field.
9. Topic 6. Fundamentals of material cutting technology.
9.1. Physical foundations of the cutting process.
It should be emphasized that for the implementation of the cutting process, it is necessary to have relative movements between the workpiece and the tool, which are divided into the main movement (or cutting movement) and the feed movement. The shaping of the surface during the cutting process is carried out with a different number of movements. The spatial shape of the part is limited by geometric surfaces. Real surfaces differ from ideal ones in that they have microroughness and waviness as a result of processing, but the methods for obtaining them are the same as for ideal geometric surfaces. Study the geometric methods of shaping the surfaces of machine parts. Depending on the type of surface to be treated, different methods of their shaping are used. In some cases, the surface shape is obtained as a result of copying the shape of the cutting blade of the tool, in others - as an envelope of a number of successive positions of the tool blade relative to the workpiece.
A graphic representation of the process of surface shaping is a processing diagram, which conditionally depicts the workpiece being processed, its fixation on the machine, indicating the position of the cutting tool relative to the workpiece and cutting movements.
The movements involved in the formation of the surface, consider the example of the processing of the outer cylindrical surface by turning. Learn the elements of cutting mode; cutting speed, feed and depth of cut, their definitions, symbols and dimensions. Using the example of a turning tool, consider the features and geometry of the cutting tool. To determine the angles of the cutter, it is necessary to know the surfaces on the workpiece and the coordinate planes.
Familiarize yourself with the concept of surface quality, which is a combination of a number of characteristics; roughness, waviness; structural state (microcracks, tears, crushed structure); hardening of the surface layer (depth and degree); residual stresses; and others. The quality of the treated surfaces determines the reliability and durability of parts and machines as a whole.
Familiarize yourself with the physical essence of the cutting process as a process of elastic-plastic deformation of the material of the workpiece, accompanied by its destruction and the formation of chips,
Consider the dynamics of the cutting process using the example of turning an outer cylindrical surface with a turning cutter on a screw-cutting lathe.
Please note that the components of the cutting force are used to calculate the elements of the machine, tool and fixture. Consider the effect of cutting force components on machining accuracy and surface finish.
Consider the physical phenomena that accompany the process of shaping surfaces by cutting: elastic-plastic deformation of the material being machined, built-up edge, friction, heat generation, tool wear. Pay special attention to the effect of these phenomena on the quality of processing. Under some processing conditions, these phenomena have a positive effect on the quality of the machined surface of the workpiece, under others - negatively.
The use of various lubricants and cooling agents has a beneficial effect on the cutting process and the quality of processing. When studying tool wear, consider its nature, wear criteria and their relationship to tool life. Note that tool life and its corresponding cutting speed should be set with regard to high productivity, surface quality and the lowest cost of machining,
Analyzing the formula for determining the main technological time when turning a cylindrical surface, please note that the surfaces of the workpieces should be processed at such cutting conditions that achieve high machining accuracy and surface quality with satisfactory performance.
When studying tool materials, please note that they must have high hardness (HRC 60), significant heat and wear resistance, high mechanical strength and toughness. Various tool materials are used for the manufacture of cutting tools: tool steels, cermet (hard) alloys, mineral ceramics, abrasive materials , diamond tools; study their characteristics and scope.
9.2. Surface treatment of workpieces with a blade (turning, drilling, planing, milling, broaching) and abrasive tools (grinding, lapping, honing).
Machining workpieces on lathes. Familiarize yourself with the characteristic features of the turning method. Please note that on the flocks of the turning group, the surfaces of workpieces that have the shape of bodies of revolution are machined.
Familiarize yourself with the types of lathes of the turning group. Learn the name and purpose of the nodes of the screw-cutting lathe.
Learn the types and designs of tools and fixtures used on lathes, and their purpose. Pay special attention to the processing of workpieces on screw-cutting lathes, as the most versatile and widespread.
Getting acquainted with turret lathes, please note that they are designed for processing batches of parts of complex shape that require the use of a large number of cutting tools. Machines are pre-configured for the processing of a specific part; equipped with devices for automatically obtaining the dimensions of the surfaces of the workpiece. In the process of processing, the tools are put into operation sequentially (one after the other) or in parallel (several at the same time). Parallel operation of tools reduces the main processing time. Vertical lathes are designed for processing heavy workpieces of large dimensions, in which the ratio of length (height) to diameter is 0.34-0.7. Pay attention to the fact that rotary machines, due to the presence of several calipers and a turret, have great technological capabilities.
Considering the processing of workpieces on multi-cutting lathes, please note that they operate on a semi-automatic cycle and are designed to process only the outer surfaces of parts such as stepped shafts. Several surfaces are processed simultaneously with different cutters mounted on longitudinal or transverse calipers, depending on their technological purpose. When studying automatic and semi-automatic machines, pay attention to the high productivity in the manufacture of large batches of parts and the classification of automatic and semi-automatic machines. Learn the basic schemes of automatic lathes and semi-automatic parallel and sequential processing, their areas of application and technological capabilities.
Familiarize yourself with the technological requirements for the design of machine parts processed on lathes.
9.3. Processing workpieces on drilling machines.
Familiarize yourself with the characteristic features of the drilling method. Drilling machines are designed for making and processing holes with various cutting tools (drills, countersinks, reamers, taps). Study the cutting tool used, fixtures for fixing workpieces and tools, their purpose and capabilities. Familiarize yourself with the classification of drilling machines. Study the name and purpose of the nodes vertically - and radial drilling machines, note that the latter is used to process holes in large-sized workpieces. Learn the types of work performed on drilling machines. The processing of deep holes, in which the length is more than five diameters, causes certain difficulties. The cutting tools are drills of a special design. Considering the scheme of deep drilling, pay attention to the supply of cutting fluid and the removal of chips from the cutting zone.
Please note that the use of aggregate machines allows you to process workpieces simultaneously with several tools.
9.4. Processing workpieces on boring machines.
Familiarize yourself with the characteristic features of the boring method. On boring machines, holes, external cylindrical and flat surfaces, ledges, grooves, and less often conical holes in workpieces such as housings are machined. Consider the versatility of a boring machine by studying surface treatment patterns with various tools. It is advisable to study the scheme of boring holes against the background of a simplified view of the machine, considering the movements of its nodes and their technological purpose. When studying diamond and jig boring machines, pay attention to their design features and technological capabilities. On diamond boring machines, the holes are finished with diamond and carbide cutters. Coordinate boring machines are designed for processing holes, planes and ledges with high accuracy of their location. Familiarize yourself with the technological requirements for the design of machine parts processed on machines of the drilling and boring group.
9.5. Processing of blanks on planing and slotting machines. Familiarize yourself with the characteristic features of the planing and chiseling processing method. Learn the types of planers. Please note that the machines are designed for processing flat surfaces, grooves, grooves, ledges, etc.
When studying the components and movements of the cross planer, note that the cutting process is intermittent and the removal of material occurs only during the direct (working) stroke. Studying the formation of surfaces on cross-longitudinal planers and slotting machines, understand the difference in cutting patterns.
Familiarize yourself with the technological requirements for the design of machine parts processed on planing and slotting machines.
9.6. Processing of workpieces on broaching machines.
Familiarize yourself with the characteristic features of the broaching method. Learn the types of broaching machines and types of broaches. Please note that broaching is a progressive method that ensures high quality and productivity of processing. Almost any surface is obtained by broaching - external and internal, the size of which does not change along the length. Only one movement is involved in the formation of surfaces - the cutting movement, and the removal of the allowance is carried out due to the difference in the sizes of the cutting teeth of the broach.
Study the design of the cutting tool using the example of a round broach. When studying continuous broaching, pay attention to the high productivity of these machines. Familiarize yourself with the technological requirements for the design of machine parts processed on broaching machines.
9.7. Processing workpieces on milling machines.
Familiarize yourself with the characteristic features of the milling method. Milling processes horizontal, vertical, inclined and shaped surfaces, ledges and grooves of various profiles. Please note that the processing is carried out with multi-blade cutting tools - milling cutters, which have a large range of designs and sizes, depending on the technological purpose.
Learn the types of milling machines, features and geometry of cylindrical and face mills.
Please note that the dividing heads used on milling flocks serve to periodically rotate the workpieces to the required angle and to rotate them continuously when milling helical surfaces.
When studying the processing of workpieces on longitudinal milling machines, note that they are multi-spindle machines, and the workpiece has only longitudinal feed; designed for processing workpieces of large mass and size,
A feature of drum milling machines is the presence of a drum with a horizontal axis of rotation, on the faces of which workpieces are installed.
When studying the processing of contoured and volumetric shaped surfaces on copy-milling machines, note that the trajectory of the relative movement of the workpiece and cutter is the resulting speed of two or more movements.
Familiarize yourself with the technological requirements for the design of machine parts processed on milling machines,
9.8. Processing gears on gear-cutting machines.
Study the essence of tooth profiling by copying (formation of a tooth profile by shaped cutters) and running-in (bending around) - the formation of a tooth profile as an envelope of successive positions of the cutting blades of the tool relative to the workpiece.
Please note that for cutting gears according to the running-in method, worm modular cutters, gear cutters and gear cutters are used. The worm modular cutter is a screw with wire rods cut perpendicular to the bars. The gear cutter is a gear wheel, the teeth of which have an involute profile. The gear cutter has a prismatic shape with appropriate sharpening angles and a straight cutting blade.
Understand that gear-cutting machines that cut the teeth of wheels using the running-in method are divided into types depending on the technological method of processing (gear-milling; gear-shaping, gear-cutting, gear-drawing, etc.).
Gear hobbing machines are designed for cutting cylindrical spur, helical and worm wheels, with a worm modular cutter according to the running-in method. The workpiece and the cutter are given movements corresponding to the engagement of the worm pair. The lateral surface of the tooth is formed as a result of the coordinated and continuous rotation of the workpiece and the cutter. The shape of the tooth along the width of the cylindrical wheel is formed by the movement of the cutter along the axis of the workpiece, and when cutting the worm wheel, by the movement of the workpiece in the radial direction. When cutting a cylindrical helical gear to obtain a helical tooth, the workpiece receives additional rotation. To coordinate the movements of the workpiece and the tool in the process of cutting teeth on a gear-cutting machine, the corresponding guitars of replaceable gears are tuned; speed, dividing, feed and differential.
On gear shaping machines, cylindrical gears of external and internal gears with straight and oblique teeth are cut. Please note that gear shaping is one of the main ways of cutting gears of internal gears and multi-rim wheels (blocks). The cutting of gears is carried out by cutters according to the running-in method, which is based on the engagement of two cylindrical gears.
Study the cutting of bevel spur gears on gear cutting machines using the running method. The method is based on the engagement of two bevel gears, one of which is flat. The cut conical wheel (blank) is engaged with the producing flat bevel wheel, in which the teeth are limited by planes converging at a common apex and have the shape of a rack tooth. The cutting tool is two gear cutters, forming one cavity of the producing wheel. On gear-broaching machines with dividing automatic devices, spur gears with straight teeth are produced by successive pulling.
Familiarize yourself with the technological requirements for gear designs,
9.9. Processing workpieces on grinding machines.
Familiarize yourself with the characteristic features of grinding. Please note that grinding is a method of finishing workpiece surfaces with abrasive tools consisting of a large number of abrasive grains with sharp edges and high hardness. Learn the characteristics of grinding and diamond wheels. Pay attention to wear and dressing of tools, Understand that grinding is advisable to use to obtain high accuracy and surface quality, as well as for processing highly hard materials,
Studying round - and surface grinders, pay attention to their wide versatility.
When studying internal grinding machines, consider the formation of internal cylindrical surfaces in a stationary and rotating workpiece. The first processing method is used when grinding holes in large workpieces of complex shape. Centerless grinding is used to process a batch of parts of the same type. Processing is carried out with longitudinal and transverse feed. Please note that the workpiece receives a longitudinal feed due to the rotation of the axis of the leading circle in a vertical plane. Learn the essence of belt and diamond grinding.
Familiarize yourself with the technological requirements for the design of machine parts processed on grinding machines.
9.10. Finishing methods of processing.
Familiarize yourself with the characteristic features of surface finishing methods. Understand that finishing methods are used to finish and give surfaces high precision, quality and reliability. Finishing methods of surface treatment (lapping, polishing, processing with abrasive belts, abrasive-liquid processing, honing, superfinishing) are based on the use of fine-grained abrasive powders and pastes as a tool material.
Please note that a feature of the kinematics of the process of finishing processing methods is the complex relative movement of the tool and the workpiece, in which the trajectories of the movement of abrasive grains should not be repeated.
Considering the methods of finishing the teeth of gears, note that they provide an opportunity to improve the performance of gears (smooth operation, fatigue resistance, noiselessness, etc.).
When finishing methods for processing gear teeth by shaving, grinding and honing, the side surfaces of the teeth are profiled by running or copying. Shaving is used for finishing raw (non-hardened) gears, and grinding and honing are used for hardened ones.
Bibliography
1. et al. Technology of structural materials. M., 1977.
2. Technology of metals and other structural materials. Ed. and. L., 1972.
3. , Leontiev. M., 1975.
4. , Stepanov foundry. M.: Mashinostroenie, 1985.
5. Dimensional stamping. Under total ed. M.: Mashinostroenie, 1973.
6. Semenov and forging. Moscow: Higher school, 1972.
7. Machines and equipment of machine-building enterprises. and others. L.: Polytechnic, 1991.
8., Kalinin processing, blanks and allowances in mechanical engineering. Technologist's Handbook. - M .: Mashinostroenie, 1976.
9. Romanovsky on cold stamping. - 6th ed., revised. and additional - L .: Mashinostroenie, 1979.
10., "Technological processes of machine-building production" M: Educational literature, 2001. in 3 t.
11., "Technology of structural materials and materials science" Textbook for universities. - M: Higher school, 1990.
1. The purpose and objectives of the study of the discipline, its place in the educational process .............................................. ................................................. ...... | |
3. Laboratory workshop ............................................... ............. | |
4. Topic 1. Introduction to technology .............................................. ........ | |
5. Topic 2. Fundamentals of metallurgical production of ferrous and non-ferrous metals .............................................................. ................................... | |
6. Topic 3. Fundamentals of technology for the production of castings from ferrous and non-ferrous metals .............................................. ................................. | |
7. Topic 4. Fundamentals of metal forming technology ... | |
8. Topic 5. Fundamentals of technology for the production of welded products ... | |
9. Topic 6. Fundamentals of material cutting technology... | |
10. References ............................................................... ....................... |
Compiled by:
Olga Vladimirovna Martynenko
Andrei Eduardovich Wirth
Technological processes in mechanical engineering. Part I
Guidelines
Templan 2009, pos. No. 2K.
Signed for printing. Format 60×84 1/16.
Sheet paper. Offset printing.
Conv. oven l. 2.13. Conv. ed. l. 1.94.
Circulation 100 copies. Order No.
Volgograd State Technical University
400131 Volgograd, ave. them. , 28.
RPK "Polytechnic"
Volgograd State Technical University
400131 Volgograd, st. Soviet, 35.
 |
Department of technology and organization of machine-building production
Discipline
"Technological foundations of mechanical engineering" (TOM)
Lecture notes
E.P. Vyskrebentsev
For students of the specialty "Metallurgical equipment"
3rd day course
4th year of distance learning
Main
1. Kovshov A.N. Mechanical engineering technology: a textbook for universities. - M .: Mashinostroenie, 1987
Additional.
2. Gorbatsevich A.F., Shkred V.A. Course design for engineering technology. - Minsk: Higher school, 1985.
3. Vorobyov A.N. Engineering technology and machine repair: Textbook. - M .: Higher School, 1981.
4. Korsakov V.S. Engineering technology. - M .: Mashinostroeniya, 1987.
5. Reference technologist-machine builder: in 2 books. under. ed. Kosilova A. G, - 3rd ed. - M .: Mashinostroenie, 1985.
6. Balabanov A.N. A brief guide to the technologist-machine builder. – M.:
Ed. standard. 1992.
INTRODUCTION 5
1 TYPES OF PRODUCTION, FORMS OF ORGANIZATION AND TYPES
TECHNOLOGICAL PROCESSES 6
1.1 Types of production 6
1.2 Types of technological processes 9
1.3 The structure of the technological process and its main
characteristics 11
1.3.1 Process characteristics 15
1.4 The complexity of the technological operation 16
1.5 Basic principles of process design 21
2 PRECISION MACHINING 23
2.1 Accuracy and its determining factors 23
3 BASIC BASES AND WORKING BASES 27
3.1 Fixing error ε z, 36
3.2 The error in the position of the workpiece ε pr, caused by
fixture inaccuracy 37
3.3 Positioning the workpiece in fixture 38
4 SURFACE QUALITY OF MACHINE PARTS AND
BLANKS 41
4.1 Influence of technological factors on the value
roughness 41
4.2 Methods for measuring and evaluating surface quality 46
5 PREPARING MACHINE PARTS 49
5.1 Selection of the initial workpiece and methods of its manufacture 49
5.2 Determination of machining allowances 51
6 MAIN STAGES OF DESIGNING TECHNOLOGICAL
MACHINING PROCESSES 60
6.1 General provisions for the development of technological
processes 60
6.2 Selection of process equipment 63
6.3. Tooling selection 64
6.4. Choice of controls 65
6.5. Forms of organization of technological processes and their
development 65
6.6. Development of batch processes 67
6.7. Development of standard technological processes 70
7 TECHNOLOGY OF MANUFACTURING STANDARD PARTS 72
7.1 Shaft technology 72
7.2 Technology for the production of body parts 82
7.2.1 Technological route for processing workpieces
buildings 84
7.3 Cylinder technology 92
7.4 Machining gears 94
7.4.1 Design features and technical requirements for teeth
Chat wheels 94
7.4.2 Machining gear blanks with a central hole. 95
7.4.3 Gear cutting 97
7.4.4 Production of large gears 100
7.4.5 Machining workpieces before cutting teeth 101
7.5 Lever technology 102
8. TECHNOLOGICAL ASSEMBLY PROCESSES 111
INTRODUCTION
Engineering technology is a science that studies the patterns of machine manufacturing processes in order to use these patterns to ensure the production of machines of a given quality, in the quantity established by the production program and at the lowest national economic costs.
The technology of mechanical engineering developed with the development of large-scale industry, accumulating appropriate methods and techniques for the manufacture of machines. In the past, mechanical engineering technology was most developed in gun shops and factories, where weapons were manufactured in large quantities.
So, at the Tula Arms Plant back in 1761, for the first time in the world, the manufacture of interchangeable parts and their control using calibers was developed and introduced.
Mechanical engineering technology was created by the works of Russian scientists: A.P. Sokolovsky, B.S. Balakshina, V.M. Kovana, B.C. Korsakov and others
Mechanical engineering technology includes the following areas of production: casting technology; pressure treatment technology; welding technology; machining technology; machine assembly technology, i.e., machine building technology covers all stages of the process of manufacturing machine-building products.
However, mechanical engineering technology is usually understood as a scientific discipline that studies mainly the processes of machining blanks and assembly of machines, as well as the methods of their manufacture that affect the selection of blanks. This is explained by the fact that in mechanical engineering, the specified forms of parts with the required accuracy and quality of their surfaces are achieved mainly by mechanical processing. The complexity of the machining process and the physical nature of the phenomena occurring in this process is caused by the difficulty of studying the entire complex of issues within one technological discipline and led to the formation of several such disciplines: metal cutting; cutting tools; metal cutting machines; fixture design; design of machine-building shops and factories; interchangeability, standardization and technical measurements; technology of structural materials; automation and mechanization of technological processes, etc.
1 TYPES OF PRODUCTION, FORMS OF ORGANIZATION AND TYPES
TECHNOLOGICAL PROCESSES
1.1 Types of production
Type of production- the classification category of production, allocated on the basis of the breadth of the range, regularity, stability and output of products.
The volume of output of products - the number of products of a certain name, size and design, manufactured or repaired by the association, enterprise or its division during the planned time interval.
Implement the following types of production: single; serial; mass. One of the main characteristics of the type of production is the coefficient of consolidation of operations. The coefficient of fixing operations is the ratio of the number of all various technological operations performed or to be performed during the month to the number of jobs.
Single production - production, characterized by a wide range of manufactured or repaired products and a small output of products.
In unit production, products are made in single copies, various in design or size, and the repeatability of these products is rare or completely absent (turbine construction, shipbuilding). In this type of production, as a rule, universal equipment, fixtures and measuring tools are used, the workers are highly qualified, the assembly is carried out using locksmith work, i.e. on site, etc. The machines are located on the basis of uniformity of processing, i.e. - sections of machine tools are created designed for one type of processing - turning, planing, milling, etc.
Transaction consolidation ratio > 40.
Mass production - production, characterized by a limited range of products manufactured or repaired by periodically repeating production batches.
Depending on the number of products in a batch or series and the value of the coefficient of consolidation of operations, small-scale, medium-scale and large-scale production is distinguished.
The coefficient of consolidation of transactions in accordance with the standard is taken equal to:
a) for small-scale production - over 20 to 40 inclusive;
b) for medium-scale production - over 10 to 20 inclusive;
c) for large-scale production - over 1 to 10 inclusive.
The main features of serial production: machines are used in various types: universal, specialized, special, automated; personnel of various qualifications;
work can be done on customized machines; both markings and special devices are used; no-fit assembly, etc.
The equipment is located in accordance with the subject form of work organization.
Machines are arranged in a sequence of technological operations for one or more parts that require the same order of operations. In the same sequence, obviously, the movement of parts (the so-called subject-closed sections) is also formed. Processing of blanks is carried out in batches. At the same time, the time for performing operations on individual machines may not be consistent with the time for operations on other machines.
Manufactured parts are stored during operation at the machines and then transported as a whole batch.
Mass production - production, characterized by a narrow nomenclature and a large volume of output of products that are continuously manufactured or repaired for a long time.
The coefficient of consolidation of operations for mass production is taken equal to one.
Technological processes in mechanical engineering Lecture 1 INTRODUCTION NA Denisova, Associate Professor, Department of Mechanical Engineering, Ph.D. ped. Sciences
Lecture plan 1 Brief description of the studied discipline 2 Classification of technological processes 3 Basic concepts and definitions
Brief description of the studied discipline Technology is the science of the methods by which it is possible to implement the production process in order to obtain a finished product with quality parameters that provide its required operational properties. Part of the production process in relation to mechanical engineering is a technological process, or a certain sequence of actions necessary to obtain structural materials, blanks, parts, kits, assemblies and machines as a whole with specified quality parameters l
Brief description of the studied discipline l The purpose of studying the discipline is to master the terminology and methodology used in the design of technological and production processes in mechanical engineering, as well as in their implementation at manufacturing enterprises.
Classification of technological processes Technological processes are classified according to four criteria: l Shaping l Quality parameters l Productivity of manufacturing products or a batch of products l Cost of manufacturing products.
Classification of technological processes On the basis of "Shaping", the entire technology of structural materials is divided into stages - processing stages: l l Metallurgy (production of metals and alloys) Production of blanks (casting, pressure treatment, welding, powder metallurgy methods) Machining (cutting methods, surface plastic deformation) Assembly production (creation of movable and fixed joints of parts by mechanical, electrical methods, welding ...)
Classification of technological processes The attribute "Quality parameters" is characterized by quality groups, including: chemical composition l structure and physical and mechanical properties of the main volume of the workpiece or part and their surface layers l geometric shape l accuracy of dimensions, shape and relative position of surfaces l surface microgeometry l
Classification of technological processes l The characteristic "Productivity of the manufacture of products or a batch of products" is characterized by the time required to manufacture a product or a batch of products l The characteristic of the sign "Cost of manufacturing a product" is the total cost of manufacturing one product.
Technological process l Technological process is a part of the production process that contains purposeful actions to change and (or) determine the state of the object of labor l Technological process is a set of processing methods: manufacturing, changing the state, properties, shape, raw materials, materials - carried out in the production process products
Basic concepts and definitions Term Definition GENERAL CONCEPTS 1. Technological process Process D. Technologischer Prozeß Fertigungsablauf E. Manufacturing process F. Precédé de fabrication 2. Technological operation Operation D. Operation; Arbeitsgang E. Operation F. Opération A part of the production process that contains purposeful actions to change and (or) determine the state of the object of labor. Notes: 1. The technological process can be attributed to the product, its component parts or to the methods of processing, shaping and assembly. 2. The objects of labor include blanks and products. The finished part of the technological process performed at one workplace,
Basic concepts and definitions 3. Technological method Method 4. Technological base D. Technologische Basis 5. Processed surface D. Zu bearbeitende Fläche A set of rules that determine the sequence and content of actions when performing shaping, processing or assembly, movement, including technical control, testing technological process of manufacturing or repair, established regardless of the name, size or design of the product Surface, combination of surfaces, axis or point used to determine the position of the object of labor in the manufacturing process. Note. A surface, a combination of surfaces, an axis or a point belongs to the object of labor. The surface to be processed. impact in the process
Basic concepts and definitions 6. Technological document Document D. Technologisches Dokument 7. Execution of a technological document Execution of a document A graphic or text document that alone or in combination with other documents defines the technological process or operation of manufacturing a product A set of procedures necessary for the preparation and approval of a technological document in accordance with the procedure established by the enterprise. Note. The preparation of the document includes its signing, approval, etc.
Basic concepts and definitions 97. Material The initial object of labor, the manufacture of the product consumed for 98. Basic material D. Grundmaterial E. Basic material F. Matière première Material of the initial workpiece. Note. The base material refers to the material whose mass is included in the mass of the product during the technological process, for example, the material of the welding electrode, solder, etc. 99. Auxiliary material D. Hilfsmaterial E. Auxiliary material F. Matière auxiliaire Material consumed during the technological process in addition to the main material. Note. Auxiliary materials can be materials consumed during coating, impregnation, welding (for example, argon), soldering (for example, rosin), hardening, etc.
Basic concepts and definitions 100. Semi-finished product D. Halbzeug E. Semi-finished product F. Demi-produit An object of labor subject to further processing at a consumer enterprise 101. A blank D. Rohteil E. Blank F. Ebauche 102. Initial blank D. Anfangs-Rohteil E. Primary blank F. Ebauche première Blank before the first technological operation
Basic concepts and definitions (Changed edition, Amendment, IUS 6-91) 104. Casting D. Gußstück E. Casting 105. Forging D. Schmiedestück E. Forging Product or blank obtained by the technological method of casting Product or blank obtained by technological methods of forging, die forging or rolling. Notes: 1. Forged forging - forging obtained by the technological method of forging. 2. Stamped forging - a forging obtained by the technological method of volumetric stamping. 3. Rolled forging - a forging obtained by the technological method of rolling from long products. (Changed edition, Amendment, IUS 6-91) 106. Product according to GOST 15895-77
Basic concepts and definitions 107. Component product A supplier's product used as an integral part of a product manufactured by the manufacturer. Note. Components of a product can be parts and assembly units 108. Typical product D. Typenwerkstück E. Typified workpiece F. Pièce type A product belonging to a group of products of a similar design, having the largest number of design and technological features of this group 109. Assembly kit D. Montagesatz E Assembly set F. Jeu de montage
USED INFORMATION SOURCES GOST 3. 1109 -82 Terms and definitions of basic concepts Gotseridze, RM Shaping processes and tools: a textbook for students. medium institutions. prof. education / R. M. Gotseridze. - M .: Publishing Center "Academy", 2007. - 384 p. 3. Material science and technology of structural materials: a textbook for students. in. textbook institutions / V. B. Arzamasov, A. N. Volchkov, V. A. Golovin and others; ed. V. B. Arzamasova, A. A. Cherepakhina. - M .: Publishing Center "Academy", 2007. - 448 p. 4. Fundamentals of mechanical assembly production: Textbook for mechanical engineering. specialist. universities A. G. Skhirtladze, V. G. Osetrov, T. N. Ivanova, G. N. Glavatskikh. - M: ITs MSTU "Stankin", 2004. - 239 p. 5. Skhirtladze, A. G. Design of non-standard equipment: textbook / A. G. Skhirtladze, S. G. Yarushin. - M .: New knowledge, 2006. - 424 p. 12.
The production process in mechanical engineering is the totality of all stages that semi-finished products go through on the way to their transformation into finished products: metalworking machines, casting machines, forging and pressing equipment, devices and others.
At a machine-building plant, the production process includes:
Preparation of materials and blanks for further processing, storage;
Various types of processing (mechanical, thermal, etc.);
Assembly of products and their transportation, quality control of processing or assembly at all stages of production
Transportation of blanks and products through workshops and sections or the entire plant;
Finishing, painting and packaging,
Storage of finished products.
The best result is always given by the production process in which all stages are strictly organizationally coordinated and economically justified.
A technological process is a part of the production process that contains actions to change and then determine the state of the subject of production. As a result of the execution of technological processes, the physical and chemical properties of materials, the geometric shape, dimensions and relative position of the elements of parts, the quality of the surface, the appearance of the production object, etc. change. The technological process is carried out at the workplace. The workplace is a part of the workshop in which the relevant equipment is located. The technological process consists of technological and auxiliary operations (for example, the technological process of processing a roller consists of turning, milling, grinding and other operations).
The production program of a machine-building plant contains a range of products manufactured with an indication of their types and sizes, the number of products of each item to be manufactured during the year, a list and quantity of spare parts for manufactured products. On the basis of the general production program of the plant, detailed production programs are assembled for the workshops, which determine the name, quantity, black and net weight of the parts that must be manufactured in this workshop or are manufactured in several workshops. A production program is drawn up for each workshop and one summary, indicating which parts and in what quantity pass through each workshop. When compiling detailed programs for workshops, spare parts for manufactured machines are attached to the total number of parts, as well as to ensure uninterrupted operation for a given period. The number of spare parts is taken as a percentage of the number of main parts.
The production program is accompanied by drawings of general views, drawings of assembly units and individual parts, specification of parts and specifications for their manufacture and delivery.
3. Mechanical and physical properties of materials. Technological and operational properties of materials.
Basic properties of metals and alloys.
The properties of metals are divided into mechanical, physico-chemical, technological and operational.
The main mechanical properties include strength, hardness, ductility, impact strength, fatigue strength. An external load induces stress and deformation in a solid body. Stress is a force related to the cross-sectional area, MPa.
Deformation is a change in the shape and size of a body under the influence of external forces or as a result of processes that occur in the body itself (for example, phase transformations, shrinkage, etc.). The deformation can be elastic (disappearing after the load is removed) and plastic (remaining after the load is removed). With an increase in the load, the elastic deformation passes into plastic; with a further increase in the load, the destruction of the body occurs.
Strength is the ability of a solid body to resist deformation.
or failure under static or dynamic loads. Strength is determined by special mechanical tests of samples made from the material under study.
To determine the strength under static loads, the samples are tested in tension, compression, bending, and torsion. Tensile test is required. Strength under static loads is evaluated by tensile strength and yield strength; temporary resistance is the conditional stress corresponding to the greatest load preceding the destruction of the sample;
Yield stress is the stress at which the plastic flow of a metal begins.
Strength under dynamic loads is determined according to test data:
On impact strength (destruction by impact of a standard sample on a copra),
Fatigue strength (determining the ability of a material to withstand, without collapsing, a large number of repeated-variable loads),
Creep (determination of the ability of a heated material to slowly and continuously deform under constant loads).
The most commonly used impact test.
Plasticity is the ability of a material to receive a permanent change in shape and size without breaking. Plasticity is characterized by elongation at break, %.
Hardness is the ability of a material to resist penetration into it.
another body that does not receive residual deformations. The value of hardness and its dimension for the same material depends on the measurement method used. Hardness values determined by various methods are recalculated from tables and empirical formulas. For example, Brinell hardness (HB, MPa) is determined from the ratio of the load P applied to the ball to the surface area of the resulting ball print F otp: HB=P/Fotp.
Impact strength - the ability of metals and alloys to resist the action of shock loads.
The physical properties of metals and alloys include melting point, density, temperature coefficients of linear and volume expansion, electrical resistance and electrical conductivity.
The physical properties of alloys are determined by their composition and structure.
Chemical properties include the ability to chemically interact with aggressive media, as well as anti-corrosion properties.
The ability of a material to undergo various methods of hot and cold working is determined by its technological properties.
The technological properties of metals and alloys include casting properties, deformability, weldability and machinability with a cutting tool. These properties make it possible to perform form-changing processing and obtain blanks and machine parts.
Casting properties are determined by the ability of the molten metal
or alloy to fill the mold, the degree of chemical heterogeneity over the cross section of the resulting casting, as well as the amount of shrinkage - reduction in size during crystallization and further cooling.
Deformability is the ability to take the desired shape under
the influence of an external load without destruction and at the lowest resistance to the load.
Weldability is the ability of metals and alloys to form permanent joints of the required quality.
Machinability refers to the ability of metals to be machined. Machinability criteria are cutting conditions and the quality of the surface layer.
Technological properties often determine the choice of material for a structure. Developed materials can be introduced into production only if their technological properties meet the necessary requirements.
Modern automated production, equipped with flexible control systems, often imposes special requirements on the technological properties of the material, which should allow the implementation of a complex technological process at all stages of obtaining a product with a given rhythm: for example, welding at high speeds, an accelerated rate of cooling of castings, cutting elevated modes, etc., while providing the necessary conditions - high quality of the products obtained.
The operational properties, depending on the operating conditions of the machine or structure, include wear resistance, corrosion resistance, cold resistance, heat resistance, heat resistance, anti-friction material, etc.
Wear resistance is the ability of a material to resist surface fracture under the action of external friction.
Corrosion resistance - the resistance of the alloy to the action of aggressive acidic and alkaline media.
Cold resistance - the ability of an alloy to maintain plastic properties at temperatures below 0 degrees Celsius.
Heat resistance - the ability of an alloy to maintain mechanical properties at high temperatures.
Antifriction - the ability of an alloy to run in to another alloy.
These properties are determined depending on the operating conditions of machines or structures by special tests.
General information about technology
Technology - a scientific description of the methods and means of production in any branch of industry (technology of mechanical engineering, agriculture, metallurgy, transport). The main types of technologies are: mechan. and chem. As a result of mechanical technology, based mainly on mechanical action on the material being processed in a certain sequence, its shape, dimensions or physical and mechanical properties change. Chemical technology processes include the chemical processing of raw materials, as a result of which the raw materials completely or partially change their chemical composition or state of aggregation, i.e. acquires a new quality. The concept of technology is applicable to sectors of the economy in which it is possible to single out not only the methods, methods and techniques of labor, but also to study the objects and means of labor, as well as their use in creating products. The rapid development of technology is one of the main conditions for scientific and technical. progress, expansion of industrial production, ensuring the release of competitive products. The market economy involves the development and development of new technologies. Especially where the improvement of old methods cannot contribute to the improvement of economic indicators (machine and instrumentation). Progress in the technology of science and technology is associated with advances in the field of chemistry. technologies, technologies of plastic masses and materials science. The creation of new materials makes it possible to create new machines with higher performance and more intensive operation. The problem of anticorrosion protection of materials is topical. The progressiveness of technology is assessed by the level of technology, which is understood as an indicator characterizing the progressiveness of the technological processes and equipment used in the production.
Production and technological process in mechanical engineering; main stages of machine production
The production process is the totality of all the actions of people and production tools necessary for the manufacture or repair of products at a given enterprise. It covers the preparation of means of production and the organization of maintenance of workplaces, the processes of manufacturing, storing and transporting blanks of machine parts and materials, assembly, control, packaging and marketing of finished products, as well as other types of work related to the manufacture of manufactured products. The production process is divided into main, auxiliary, serving. The main one is connected with the manufacture of parts and the assembly of machines and mechanisms from them. The auxiliary includes the manufacture and sharpening of tools, maintenance and repair of equipment, installation of new equipment. Service production includes warehouses, transport, cleaning of the enterprise's workshops, and a power supply unit. Depending on the stage of production, there are procurement, processing and assembly phases. The procurement includes foundry production, pressure treatment. Technological process - a part of the production process, containing actions to change and then determine the state of the object of labor. As a result of the technological process of processing, there is a change in the size, shape, or physical and mechanical properties of the material being processed. The technological process is divided into separate operations, which are characterized by the presence of a workplace, technological equipment, technological equipment, i.e. by what the worker affects the object of labor (workpiece). The list of items of products that need to be released in the time interval, indicating the number of products, their names, types and sizes, the deadline for each item is called. production program. Depending on the production program, the nature of the production process, there are: single, serial and mass production.