In order to quickly and correctly process a part, it is necessary to foresee the most appropriate processing sequence in advance, select the machine on which the processing should be performed, select the cutting and measuring tools, as well as the fixtures necessary for processing, and assign cutting modes. These data, which determine the entire process of processing the workpiece until it becomes a finished part, are set in advance technical document, make up technological process.
The technological process is the basis of the organization of all production. Based on the developed technological process the amount of necessary equipment, tools and fixtures, the number of workers and service personnel to carry out a given program for the production of parts.
The technological process connects all the links of production. Therefore, exact observance of the established technological process is a necessary condition. proper organization production. The technological process in production is a law that no one can violate.
2. Elements of the technological process
A technological process may consist of one or more operations.
Operation called the finished part of the technological process of processing one or more parts, which is performed on one machine by one worker.
A new operation begins when the worker, having completed part of the processing of the entire batch of parts, proceeds to further processing of the same batch of parts, or proceeds to the processing of new parts.
Let us explain the concept of “operation” using the example of processing a coupling cone (Fig. 281), made from a cast billet with a hole with a diameter of 38 mm.
On fig. 282 shows a processing sequence diagram for the case where a worker processes each part from start to finish. Such a construction of the technological process is used only in the manufacture of single parts. The workpiece is installed in the chuck and processed on one side: the end is trimmed (Fig. 282, a); the cylindrical surface is turned to 80X 4 to a length of 65 mm (Fig. 282, b); hole 40A 3 is bored (Fig. 282, c); a chamfer is machined 2 X 45 ° (Fig. 282, d); a groove 10 mm wide up to 064 mm is machined (Fig. 282, e). Then the workpiece is installed with a turned surface 80X 4 in a chuck with bored cams; the second end is cut to a size of 90 mm (Fig. 282, e); a chamfer 2x45 ° is machined (Fig. 282, g); a cone is turned with a slope angle of 10 ° (Fig. 282, h). After the final production of the first part, the worker proceeds to the production of the next part. The technological process constructed in this way consists of one operation.
On fig. 283 shows an example where a batch of the same parts is processed in two operations. First, all parts of the batch are processed sequentially in all sizes on the one hand (Fig. 283, a-d) - this is the first operation. Then, for all parts of the batch, successively installed by the other side, the remaining surfaces of the part are processed (Fig. 283, e-h). This constitutes the second operation of the technological process.
Sometimes the technological process is divided into smaller operations (Fig. 284. For example, first, sequentially, for all parts of the batch, the end is cut and the outer cylindrical surface is turned (Fig. 284, a-b); this will be the I operation. Then the end is cut to a size of 90 mm for all parts of the batch, a hole 40A 3 is bored through and a chamfer 2 x 45 ° is turned (Fig. 284, cd) - this will be the second operation. Then the conical surface is turned separately (Fig. 284, e), which is the third operation. Finally, a groove is machined with a width of 10 + 0.1 mm to 64 mm and a chamfer 2 X 45 ° (Fig. 284, railway). This will be the IV operation.
Thus, an operation can be simple, containing one or two types of processing (see Fig. 284, f, g, h), and complex, containing several types of processing.
Installation . An operation can consist of one or more settings. Set-up is the part of the operation that takes place between the clamping of the workpiece and its release.
Consider this on the example of processing the cone of the coupling. In the first variant (see Fig. 282) the technological process consists of one operation, but in this operation there are two installations. The first installation A includes the entire processing of the workpiece on one side and boring a through hole with a diameter of 40A 3) (see Fig. 282, a-d), after which the part is removed from the machine. The second installation B begins with fixing the workpiece with the other side and includes cutting the end face to a size of 90 mm, turning a chamfer 2 X 45 ° and turning a cone (see Fig. 282, e-h).
In the second variant (see Fig. 283), when a batch of the same parts is processed in two operations, the total number of installations remains the same, but here each operation consists of one installation.
In the third option (see Fig. 284), when a batch of parts is processed in four operations, the number of installations will also be four. There may be cases when one of the operations contains two settings, and the rest - one at a time and vice versa.
Transition. An operation can consist of one or more transitions. transition called the part of the operation performed on the surfaces of the part with the same installation of tools and constant cutting conditions. The next transition begins when any of these conditions change: either the processing surface, or the cutting tool, or the cutting conditions change.
For clarification, we use the above examples of processing the coupling cone. In the manufacture of this part in one operation (see Fig. 282), the first transition consists in cutting the end (see Fig. 282, a). Processing in this case is carried out by a bent cutter with a certain cutting mode.
When turning a cylindrical surface with a diameter of 80X 4 (see Fig. 282, b), the cutter remains the same, the cutting mode does not change, only the processing surface changes: instead of the end face, the cylindrical surface of the workpiece is processed, therefore, the transition changes. Thus, turning the cylindrical surface 80X 4 is the second transition. When boring a hole (see Fig. 282, c), the processing mode, the cutting tool and the processing surface change, therefore, the transition also changes. Grooving a groove (see Fig. 282, e), where the cutter, cutting mode and processing surface change again, will be the fifth transition, cutting the second end (see Fig. 282, e) - the sixth, chamfering - the seventh, turning the cone - eighth passage.
Thus, the technological process of manufacturing the coupling cone in the first variant (see Fig. 282) consists of one operation and two installations. The first setting has five transitions, the second has three. The technological process in the second variant (see Fig. 283) consists of two operations. The first operation contains one setup and five transitions, and the second one contains one setup and three transitions. In the third option (see Fig. 284) the technological process consists of four operations and four installations; the first setting contains two transitions, the second one three transitions, the third one one transition and the fourth one two transitions.
Pass. Transitions are divided in turn into passages. The passage is the part of the transition that covers all the actions associated with the removal of one layer of metal. If the machining allowance is large and it is removed with the same tool in two steps, then in this case the transition consists of two passes. Threading with a cutter is usually done in several passes.
H. Principles of construction of the technological process
The technological process can be built:
a) according to the principle of consolidation of operations, when a large number of transitions are concentrated in one operation;
b) according to the principle of division of operations, when the processing process is divided into a number of separate simple operations, in which sometimes each transition is performed for a separate installation.
When the operations are enlarged, the coaxiality and greater accuracy of the relative position of the treated surfaces are more fully ensured, since their processing is carried out in one installation.
According to this principle, the technological process of processing the coupling cone in one operation is built (see Fig. 282).
With the enlargement of operations, as a rule, the total number of installations decreases, which is very important when processing such parts, the installation of which requires a significant investment of time.
Turret and multi-cutting lathes, semi-automatic and automatic machines work on the principle of consolidation of operations.
When dividing operations into a number of simple ones, the machine is set up to perform each operation only once for the first part of the batch, the rest of the parts are processed according to this setting.
The principle of division of operations makes it possible to widely use stops, allows for a more rational organization of the workplace, to develop the automaticity of working movements associated with the installation and removal of the workpiece, the supply and withdrawal of the cutting tool.
Splitting operations greatly increases the number of setups, so it is essential to have fast-acting fixtures to ensure fast and accurate workpiece setup for each operation.
According to the principle of division of operations, a technological process for manufacturing a coupling cone in four operations was built (see Fig. 284).
4. Choice of processing method
When processing parts, you should strive to remove all the available allowance in one pass, but this is not always possible. Usually, the workpiece to be machined has an uneven allowance due to the unevenness of its surfaces, inaccurate centering during installation, etc. Due to the uneven allowance, different parts of the machined surface are machined under different cutting conditions. This can cause in different areas of processing a different amount of pressing of the cutter and workpiece, which will affect the accuracy of the shape and dimensions of the surfaces to be machined.
Therefore, when processing surfaces where precise execution of the shape and dimensions is required (within 2-3 classes), processing is divided into roughing and finishing.
When roughing, a large part of the allowance is removed, the irregularities of the allowance are cut off, and when finishing the workpiece, they are finally processed to the required size.
When processing parts in significant batches, it is recommended that roughing and finishing be performed on different machines - peeling and finishing. This is necessary in order to extend the service life of finishing machines, which determine the accuracy and cleanliness of the machined surfaces of the part.
Individual surfaces of a part can be processed in various ways. For example, the processing of holes can be done with a drill; drill and cutter; drill and countersink; drill, countersink and reamer. At the same time, drilling with a drill is the most productive method, but the least accurate, processing with a drill, countersink and reaming is the most accurate, but the least productive.
External thread cutting can be performed with a threaded tool, threaded comb, die. In the case of small diameter threading, die cutting is the most productive.
When choosing a processing method, one should strive to use in the first place the most efficient processing methods. In cases where these methods can provide the required accuracy and surface finish, they should be used until the final production of the part. For example, if it is required to machine a hole with an accuracy of up to 0.1 mm, and the finish of the machined surface is allowed within 3, such a hole should be machined by drilling as the most productive machining method.
If high-performance processing methods cannot provide the necessary accuracy and cleanliness of the machined surface or other specifications, it is necessary to strive to perform as much of the preliminary processing as possible by high-performance methods, and to carry out the final processing in other ways, sometimes less productive, but providing the necessary technical requirements.
5. The concept of bases
For the correct construction of the technological process, it is very important to pre-select the surface on which the workpiece should be installed on the machine. Such a surface is called installation base.
Base selection is one of critical tasks, which are solved when compiling the technological process. How the basing is carried out, in most cases, depends on the execution technical requirements to the relative position of the surfaces of the parts (coaxiality, perpendicularity, etc.).
The installation base used in the first installation is called primary base. The primary base is usually used once on the first installation. On this base, the surface is usually processed, which in subsequent installations should serve as an installation base.
When choosing primary bases must proceed from the following basic provisions.
1. For the primary base should be taken such a surface of the workpiece, which allows you to prepare the base for subsequent processing of other surfaces.
Let's explain this with an example. Let it be required to process the part shown in Fig. 285. For the primary base, you should take the surface a of the flange and on this base process a cylindrical section with a diameter of 80 mm, cut the end of the flange and the end of the cylindrical section. The surface of the machined cylinder with a diameter of 80 mm will serve as the base second installation for processing the second outer end of the flange.
If the surface of an unmachined cylindrical section with a diameter of 80 mm is taken as the primary base and the flange end is machined on this base, then the base for further processing of the part on the other side will not be prepared (the machined end of the flange can serve as a base only if the part is fixed on a faceplate with a complex installation ). Therefore, the surface of the cylindrical section cannot be taken as the primary base.
2. For parts that are not processed on all surfaces, the surface that is not processed (remains in black form) should be taken as the primary base, since in this case the base surfaces will have the smallest displacement relative to the processed surfaces. For example, when processing the part shown in Fig. 286, the base should be taken as an unmachined surface a. In this case, the displacement of the hole with a diameter of 40A 3 relative to the outer surface will be the smallest.
3. For parts machined by a circle, the surfaces with the smallest machining allowance should be taken as the primary base. In this case, there will be the greatest guarantee that marriage will not work due to improper distribution of the allowance.
4. It is necessary to strive to ensure that the surfaces taken as primary bases are as clean and even as possible.
5. Surfaces taken as primary bases must allow the workpiece to be securely fixed so that machining with high-speed cutting conditions can be performed.
Reliability of fixing the workpiece is especially important in roughing, which is carried out with large chip sections. In these cases, you need to strive for maximum rigidity of the installation. Therefore, when roughing, where accuracy is not of great importance, it is recommended to widely use the combined fastening of the workpiece: at one end - into the chuck, the other - into the center of the tailstock, since this method of fastening is the most reliable.
Finishing bases called machined surfaces used as bases when performing operations on which the surfaces of the part receive the final dimensions.
When choosing a finishing base should proceed from the following basic provisions.
1. As a finishing base, one should take such a machined surface, which can serve as a base for processing as many surfaces as possible.
2. When processing precision parts, the finishing base should be, if possible, the surface on which the finished part is installed when working in the machine. In this case, the accuracy of setting the part during processing will be the greatest. For example, when processing a gear wheel (Fig. 287), it is best to take a machined hole with a diameter of 40A3 as a finishing base, since the wheel is mounted on the machine shaft with the same hole. Consider examples of the choice of finishing bases and ways of fixing workpieces on these bases.
1. When turning parts like shaft the center holes at the ends of the shaft are taken as the base. The advantage of such bases is that they allow the parts to be repeatedly installed during processing without additional alignment and without special installation devices, which is especially important in cases where the technological process is based on the principle of division of operations.
2. When turning parts like sleeve, When outside surface has the shape of a cylinder and a smooth cylindrical hole; sometimes a hole is taken as a finishing installation base, and sometimes an outer cylindrical surface.
If it is planned to take the surface of the machined hole as the finishing base, then the surface of this hole is machined in one of the first operations. The installation of the workpiece on the hole can be made on the mandrel.
When machining parts that have internal surfaces with shallow cones, a conical surface is often taken as the base. The gently sloping conical surface is a very convenient base, since it can simultaneously serve as a reliable means for fixing the workpiece during processing.
The method of fixing the workpiece on the cone provides accurate centering, quick installation and removal of the workpiece. Most often, a conical hole is used as a base, setting the workpiece with a conical hole on a conical mandrel (Fig. 288).
6. Discipline in the technological process
Strict adherence to the technological process, drawn up in the form of a technological map, that is, compliance with technological discipline, is the basic law of the normal course of production. Where the technological process is not observed, the program is usually not executed and almost always a large rejection of parts is obtained. Violation of technological discipline is unacceptable in a socialist enterprise.
However, the technological process of any production is not a dead letter, it must be constantly improved and rationalized.
In our country, turners are actively involved in rationalization work.
In socialist production, the methods of rationalizing the technological process should be the main lever for improving processing, reducing the cost of production, speeding up production and raising the quality of the product. Therefore, for the worker-innovator, there are wide opportunities for rationalizing the technological process.
However, this does not mean that it is possible to change the technology arbitrarily, without the permission of the workers in charge of the technology at the plant. Such an unauthorized change in technology, instead of benefit, can be detrimental to production.
Any improvement in the technological process proposed by the workers must be formalized in the form of a rationalization proposal; after review and approval, the improvement is made to technological documentation, i.e. becomes part of the process.
The factories have departments of workers' inventions (BRIZ), which have as their task to involve workers in the improvement of technological processes. For every completed rationalization proposal the author is paid a cash bonus, the amount of which depends on the amount of savings received.
Control questions 1. What elements does the technological process consist of?
2. Give an example of processing a part in one operation and divide it into setups and transitions.
3. What is called a passage?
4. What is the task card used for?
5. What is called the finishing base?
6. What is called the installation base?
7. What is the discipline in the technological process?
Technological process - the main part of production (production process).
The technological process consists of a number of production operations that are performed in a strictly defined sequence. A production operation is a part of the technological process performed at a specific workplace with a specific tool or on specific equipment.
Operations follow in the technological process in a strictly established order. For example, marking is followed by cutting boards into blanks for parts, then planing, trimming, making tenons, gouging nests, etc. No one will file tenons on unplaned parts or grind a part before it has been given the final shape by planing.
The degree of operational dissection of the technological process depends on the amount of work for the manufacture of this product, on the number of workers involved in the manufacture of the product, on the size of the production facility (working area), on the nature of the workplace equipment and other production conditions. The deepest division of the technological process into operations should be considered when each operation is performed in one step without changing the tool. The smaller the operation, the easier and more accessible it is to perform. Therefore, the deeper the operational breakdown of the technological process, the higher labor productivity and the less need for highly skilled workers.
The technological process can be general for the manufacture of the entire product or cover, for example, only the processing of parts, only the assembly operations or the operations of finishing products.
The technological process should not be confused with the production technology. Under the production technology, one must understand not only the sequence of operations performed, but also the methods and techniques for performing these operations. The production technology should be based on the latest achievements science and technology, taking into account the experience of innovators and innovators.
The place in production where any production operation is performed is called a workplace. Machine tools, mechanisms, stationary devices installed at the workplace, i.e. permanent devices, fixed motionless, constitute the equipment of the workplace.
From how the workplace is organized, from the provision of its tools and fixtures, from the location of materials, tools and fixtures relative to the permanent equipment of the workplace and relative to the worker himself, from the preparedness of equipment, tools and materials for work, from the quality of care for the workplace and equipment - the productivity and quality of products depend on all this.
In carpentry, as elsewhere in industry, the technological process is subdivided according to the division of production into workshops. The main workshops are cutting, drying, machine, gluing, assembly and finishing. Next are auxiliary and service shops. A service shop is, for example, a mechanical (metalworking) workshop with a saw and knife workshop. Within the workshop, the technological process is divided into processing stages. For example, the stages of the technological process in the assembly shop are the assembly of units, the assembly of combines, the cleaning and processing of the assembled elements, the assembly of the entire product. Stages of the technological process in the finishing shop: finishing preparation, initial and intermediate finishing, drying, final finishing.
The division of the technological process according to the workshops allows:
1) it is most rational to equip each workshop with machine tools, mechanisms, devices, according to the nature of the work performed in it;
2) create in the workshop best conditions labor, taking into account the peculiarities of work in it;
3) adapt the premises and equipment of the workshop to perform work in accordance with the requirements of safety, labor protection and fire protection for these types of work;
4) to manage the work of the shop most efficiently and skillfully, to exercise fuller quality control over the work;
5) rationally organize jobs.
The division of the technological process into processing stages allows:
1) place machines, mechanisms and other equipment in the best production sequence, ensure mechanized supply of materials to them;
2) organize work in teams and units.
Technological process of production
Industrial production is a complex process of converting raw materials, semi-finished materials and other objects of labor into finished products that meet the needs of the market.The production process is a set of all the actions of people and tools necessary for a given enterprise to manufacture products.
The production process consists of the following processes:
The main ones are technological processes during which changes in the geometric shapes, sizes and physical and chemical properties of products occur;
- auxiliary - these are processes that ensure the uninterrupted flow of the main processes (manufacturing and repair of tools and equipment; repair of equipment; provision of all types of energy (electricity, heat, steam, water, compressed air, etc.));
- service - these are processes associated with the maintenance of both main and auxiliary processes and do not create products (storage, transportation, technical control, etc.).
In the conditions of automated, automatic and flexible integrated production, auxiliary and service processes are combined with the main ones to one degree or another and become an integral part of the production processes, which will be discussed in more detail later.
Technological processes, in turn, are divided into phases.
Phase - a set of works, the performance of which characterizes the completion of a certain part of the technological process and is associated with the transition of the object of labor from one qualitative state to another.
In mechanical engineering and instrumentation, technological processes are mainly divided into three phases:
Procurement;
- processing;
- assembly.
The technological process consists of technological actions, operations, sequentially performed on the given object of labor.
An operation is a part of a technological process performed at one workplace (machine, stand, unit, etc.), consisting of a series of actions on each subject of labor or a group of jointly processed items.
Operations that do not lead to a change in the geometric shapes, sizes, physical and chemical properties of objects of labor are not technological operations (transport, loading and unloading, control, testing, picking, etc.).
Operations also differ depending on the means of labor used:
Manual, performed without the use of machines, mechanisms and mechanized tools;
- machine-manual - performed using machines or hand tools with the continuous participation of the worker;
- machine - performed on machines, installations, units with limited participation of the worker (for example, installation, fixing, starting and stopping the machine, unfastening and removing the part). The machine does the rest;
- automated - are performed on automatic equipment or automatic lines.
Hardware processes are characterized by the performance of machine and automatic operations in special units (furnaces, installations, baths, etc.).
Automation of technological processes
Modern computerized and automated production is characterized by a pronounced engineering desire to free people as much as possible from participation in technological processes - the humanization of production. It is unlikely that a person came into this world just to turn nuts on the assembly line of an automobile factory, sew slippers, bake pies, assemble computers or drive cars. He does all this and much more as needed. Yes, and by itself, a person in his production activity has long been no longer effective in comparison with technical means: machine tools, machines, etc.Production time “eats up” a huge part of the time of a unique human life, cuts off opportunities for the free development of individuality, deprives a person of the fullness of perception of the world around him.
Unfortunately, before the radical release of people from the sphere material production still far. At the same time, global engineering and technological ideas are emerging that, to one degree or another, pave the way for the implementation of “unmanned” production. Among such ideas, one of the most promising is the idea of flexible automated production.
Flexible automated production (FLP) allows the transition from the production of one product to another with virtually no readjustment of technological and any other equipment; if in some cases a changeover is required, then it is carried out simultaneously with the release of the previous product. Flexible manufacturing consists of flexible manufacturing systems (FMS), which are characterized by a more complete processing of parts in one workplace.
In modern and promising production the “man-machine” system becomes decisive. The man at the remote control is a typical module of any production environment which requires significant psychological stress from the worker. Techniques and technologies are constantly becoming more complex, moreover, to a certain extent, the production environment becomes hostile to humans. There is a need to green the production environment, protect the psyche of a working person, reduce their energy costs. The solution of these problems was taken over by engineering psychology.
“Today computers do everything!” - this common phrase, of course, does not mean that the computer cooks soup, manufactures a car body, assembles a video recorder, publishes a book or magazine. However, he manages the technique, industrial equipment and automation tools that already directly do the things we need.
Thus, technological processes are automated on the basis of a computer. Thanks to this, a person is freed from direct participation in production operations. The functions that he performed before, in modern production machines perform. Physical work gradually eliminated. The role of a person today is control, adjustment of equipment, production management by means of a computer - mainly mental work. Man cannot be replaced by automatic machines only where his intuition, experience, and creativity are needed.
Process development
A technological process (TP) is a sequence of actions established by the relevant technological documents, interconnected and directed at the process object in order to obtain the required result. Technological processes consist of work operations that can be linked to each other using technological transitions.Each manufacturing enterprise has developed and operates the main or permanent production process or processes. They are approved by the chief technologist of the enterprise. For greater clarity, the description of the technological process is accompanied by a flow diagram, which also goes through all stages of coordination.
The development of a technological process for a newly commissioned production is carried out on the basis of standard manufacturing processes, taking into account automation. When mastering new types of products or new technologies, temporary TPs are used.
Documents of technological processes
The technological documents used to describe and implement the TP of production depend on the industry in which it operates. specific enterprise. If in most industrial areas route maps are taken as the basis, then in the machine tool industry, operational maps are the same integral part of technological documentation as route maps.
The development of the technological process and the preparation of technological documentation are carried out in full accordance with the requirements of GOST 14.301 - 83, which is part of the Unified System for Technological Documentation (ESTD). In accordance with the provisions existing in the ESTD, technological documents for the most part refer to specialized documentation. While Technological instructions classified as general documents.
The standard provides for the following special technological documents:
A route map is used for a route or route-operational description of a technological process or for listing technological operations and movements in the production process. Contains data on equipment, material standards and labor costs, technological equipment;
a technological process map or a map for the operation being performed. It is intended to describe a specific manufacturing or repair operation. It also contains all the information necessary for the execution of the technological process;
a map of a typical technological process or a map of a group technological process that is used for the corresponding TP;
a repair process map is used to develop a repair process, and it is linked to product defects;
an operational map used to describe a specific technological operation, indicating the transitions within it;
list of technological documents, which contains full squad documents used for production at the enterprise;
other technological documents.
Process development
Usually done before construction starts. production shops. Because if we are talking about large production facilities, they are designed and built taking into account the equipment and technologies used. The future automation of technological processes is also taken into account.
The flow diagram in this case is a necessary document for designers.
Process design depends on the type of product or job, the industry sector and the annual output.
Depending on the last indicator of production, they are divided into types:
small-batch;
serial;
mass.
At the same time, the technological process of production can be classified in accordance with GOST as:
A typical TP is developed at the federal or industry level as a model for the development of production technological documents at industry enterprises;
prospective TA takes into account the use latest methods and methods of the technological process;
group technological process;
route technological process is developed for a single or small serial production. The development of the technological process in this case consists in the development of a route map without taking into account transitions;
operational process is being developed for high-volume and mass production. In addition to the route map, operational maps are being developed. And the route map itself is a list of operations specified in the sequence of execution of the technological process;
route-operational TP allows you to include a description of some operations in the route map;
a single technological process is developed for small-scale production. Such technological manufacturing processes are characterized by minimization of preparatory operations. The development of the technological process is aimed at the efficient use of technological equipment.
Process control
Industrial production is usually divided into a number of technological processes. Under the technological process is understood such processing of raw materials and semi-finished products, which leads to a change in their physical and chemical properties and transformation into finished products. In other words, the technological process is a set of mechanical, physical, chemical and other processes of purposeful processing of raw materials and semi-finished products. Each technological process is characterized by certain technological parameters that can change over time. IN chemical technology such parameters are the consumption of material and energy flows, chemical composition, temperature, pressure, substance level in technological apparatuses, etc. The set of technological parameters that completely characterize a given technological process is called a technological regime.Each technological process in the general production cycle has its own purpose, in accordance with which certain requirements are imposed on it - ensuring a given or maximum performance, a given or best quality products specified or minimal cost raw materials (semi-finished products) and energy per unit of finished product, etc.
Fulfillment of the requirements for the technological process is possible only with a targeted impact on its technological regime.
Any technological process is subject to the action of various factors, random in nature, which cannot be foreseen in advance. Such factors are called perturbations. These include, for example, random changes composition of raw materials, coolant temperature, characteristics of technological equipment, etc. Disturbing influences on the technological process cause changes in the technological regime, which, in turn, leads to a change in such technical and economic indicators of the process as productivity, product quality, consumption of raw materials and energy, etc. .P. Therefore, to ensure the given (required) technical and economic indicators, it is necessary to compensate for fluctuations in the technological regime caused by the action of disturbances.
Such a purposeful impact on the technological process is a process of management. The set of requirements implemented in the management process is called the goal of management. Finally, the controlled technological process itself, together with the technological equipment in which it takes place, is the object of control.
The control object and the devices necessary for the implementation of the control process are called the control system.
Technological process of repair
Technological repair process - a part of the production process associated with the implementation of the main work on car repair: disassembling it into units, components, parts; parts repair; assembly, testing and painting; delivery of the car to the customer. These works are performed in a certain sequence in accordance with the technological process. The elements of the technological process are the following parts.Operation - a part of the technological process of repair, performed continuously at one workplace, with a certain type of equipment, by workers of the same profession. The operation usually bears the name of the equipment with which the operation is performed. For example, an assembly operation is performed in an assembly shop using assembly equipment by a fitter, etc.
Installation - part of the operation performed on the product when changing its position relative to the equipment, tool. For example, the assembly operation of a car consists of installing the engine, gearbox, etc.
Transition - part of the operation, installation, performed on one section of the product, with one tool operating in the same mode. For example, the engine installation consists of several transitions: engine slinging; lift, move, put the engine on the frame; fasten the engine to the frame.
A passage is one of several transitions that follow each other. For example, the transition - slinging the engine consists of two passes - linking one sling on the engine on one side and securing the other end on the crane hook; the same, but with the second line and on the other side of the engine.
Working technique - part of the transition or passage, which is a complete cycle of working movements. For example, fastening one end of the sling to the engine on one side is one method, fastening the other end of the sling to the crane hook is another working method.
The working movement is the smallest moment of the operation. For example, to take a detail is a working movement.
The development of the technological process consists in the fact that for each of its elements a description of the content of the work, the necessary equipment, fixtures and tools, the complexity of the work and labor costs are established. All these data are entered into technological cards. Depending on the volume of work performed, a different depth of development of the technical process is established. For small enterprises with a small amount of work, the technical process is developed at the level of operations and installations using universal equipment and tools. The technological map indicates only the order of operations (route technological map). Works are carried out by highly qualified workers.
For service stations with a sufficiently large amount of work, the development of a technological process is carried out at the level of transitions and passages, indicating the content of work for each operation. Works are performed on special equipment (stands) using special devices and tools according to operating procedures. technological maps.
Process development is carried out separately for Maintenance TO-1, TO-2 and for repair work on current and major repairs.
The largest volume of work performed takes place during the overhaul of cars, which is carried out at specialized car repair plants.
Cars accepted for repair undergo an external washing and go to the dismantling operation. All units are removed from the car frame, the base part, they are cleaned of dirt, oil, disassembled into components and parts. Removed parts are sorted into fit, unusable and in need of repair. Suitable parts are re-assembled, unusable parts are sent for scrap, parts that require repair are restored and sent for assembly of units. The nodes are assembled into units, the units are again installed on the car frame. The assembled car is tested and handed over to the customer.
It is important to note that according to the same scheme, the development of the technological process for carrying out current repairs is carried out with the peculiarity that in this case the number is smaller and they are performed in a smaller volume.
Technological process of processing
The technological process of machining is a part of the production process that is directly related to changing the shape, dimensions or properties of the workpiece being processed, performed in a certain sequence. The technological process consists of a number of operations.An operation is a completed part of the technological process of processing one or more simultaneously processed workpieces, performed at one workplace by one worker or team. The operation begins from the moment the workpiece is installed on the machine and includes all its subsequent processing and removal of the machine. The operation is the main element in the development, planning and regulation of the technological process of processing workpieces. The operation is performed in one or more settings of the workpiece.
Installation - a part of the technological operation, performed with the constant fixing of the workpieces being processed. In the installation, separate positions of the workpiece are distinguished.
Position - a fixed position occupied by a fixed workpiece together with a fixture relative to a tool or a fixed piece of equipment to perform a certain part of an operation.
A technological operation can be performed in one or several transitions. The transition is the part of the operation, which is characterized by the constancy of the cutting tool, the processing mode and the surface to be machined. In turn, the transition can be subdivided into smaller elements of the technological process - passages. During the pass, a layer of material is removed without changing the machine settings.
The development of all these elements of the technological process largely depends on the nature of the workpiece and the allowances for its processing.
A workpiece is an object of production from which a part is made by changing the shape, size, roughness and properties of the material. Blanks are produced in foundries (castings), forging shops (forgings, stampings) or blanking shops (cut from rolled products). The method of producing blanks depends on the design requirements for the parts, material properties, etc.
When developing a technological process, it is very important to choose the right technological (installation and measuring) bases.
Under the mounting base is understood the surface of the workpiece on which it is fixed and on which it is oriented relative to the machine and the cutting tool. The mounting base used in the first operation is called the rough base, and the base that was formed as a result of initial processing and is used to fix and orient the workpiece during further processing is called the finishing base.
Measuring bases are the surfaces of the workpiece, from which the dimensions are measured when monitoring the results of processing.
When choosing technological bases, they are guided by the rules of unity and constancy of bases. According to the first rule, the same surfaces should be used as installation and measuring bases whenever possible. The second rule requires that as many surfaces as possible be processed from one base. Compliance with these rules ensures higher processing accuracy. For a rough installation base, they usually take the surface that is not subject to further processing or has the smallest allowance for processing. This avoids marriage due to insufficient allowance for this surface. The surfaces selected as mounting bases must allow the workpiece to be securely fastened.
The development of the technological process begins with the analysis of the initial data - the working drawing and the dimensions of the batch of parts (the number of workpieces of the same name to be processed). At the same time, the availability of equipment, fixtures, etc. is taken into account.
Based on the working drawing and batch sizes, the type and dimensions of the workpiece are determined. So, for a single production, workpieces are usually cut from sectional or sheet metal (in this case, the locksmith must determine the dimensions of the workpiece, taking into account processing allowances). In serial and mass production, blanks are usually obtained by casting, free forging or stamping.
For the selected workpiece, technological bases are outlined: first - roughing, then - the base for finishing.
Based on typical technological processes, the sequence and content of technological operations for processing a particular part are determined. When the sequence of processing is determined and the operations are planned, for each of them the necessary equipment, technological equipment (working and measuring tools, fixtures) and auxiliary materials (means for painting workpieces during marking, cooling and lubricants, etc.) are selected.
In the case of processing parts on machine tools, processing modes are calculated and assigned. Then the technological process is normalized, i.e., the time limit for the execution of each technological operation is determined.
State standards Unified system installed technological preparation production (ESTPP). The main purpose of the ECTPP is to establish a system for organizing and managing the process of technological preparation of production. ECTPP provides for the widespread use of progressive standard technological processes, standard technological equipment and means of mechanization and automation of production processes.
Main technological processes
The main technological processes include the processes of manufacturing products sold by the enterprise, and the auxiliary ones - the processes of manufacturing and repairing tools and equipment, repairing instruments and equipment, the service ones - energy supply, transportation of various goods, warehousing and storage of materials, components, etc. At the enterprise technological processes are carried out in workshops, which are respectively called main, auxiliary and service.The technological process is part of the production process. The technological process is the basis of any production process, is its most important part associated with the processing of raw materials, the processing of blanks, semi-finished products and their transformation into finished products. The main part of the technological process is the technological operation. An operation is a completed part of the technological process, performed at one workplace and characterized by the constancy of the object of labor, tools of labor and the method of influencing the object of labor. Operation examples; drilling holes, turning a cylindrical surface on lathe, threading, heating the workpiece before stamping, etc.
Almost any specific technological process can be considered as part of a larger complex process and a set of less complex technological processes. Any manufacturing process finished products(car, refrigerator, electric motor) can be broken down into simpler technological processes (technological processes for the manufacture of blanks, forgings, castings, stampings, their machining, hardening, painting, etc.). In turn, simple technological processes can be divided into elementary ones. An elementary technological process is the simplest process, further simplification of which leads to the loss of the characteristic features of the technological production sphere. National economy characterized by division into industries.
Industry - a set of industrial and manufacturing enterprises, research and design organizations that manufacture products that are similar in purpose and raw materials, use similar technology in the main production, and use specially trained personnel for its production. Each industry has its own specific features production, organization and economics.
The basis of the production of any product is raw materials - the material or object of labor, for the extraction or production of which labor was expended. Raw materials are classified into natural and artificial. Natural raw materials are extracted from the bowels of the earth, plants, animals, and are divided into organic (oil, wood, flax, cotton, etc.) and mineral (chalk, iron ore, salt, alumina, etc.). Artificial raw materials are obtained as a result of processing natural raw materials (acids, plastics, chemical fibers, synthetic rubbers, etc.). Artificial raw materials, like natural ones, are divided into organic (viscose, acetate fibers, etc.) and mineral (silicate, metal fibers, etc.).
The basis of the activity of each enterprise is the production process. The production process is a set of all the actions of people and tools of production necessary for a given enterprise for the manufacture or repair of manufactured products. It can contain many technological processes and includes: production preparation; receipt, transportation, control and storage of materials (raw materials, semi-finished products); technological processes for the manufacture of blanks, parts, assemblies and assemblies; production and repair of technological equipment, maintenance and repair of equipment, technological processes of waste disposal and much more. Technological processes are divided into main, auxiliary and service.
Trade and technological process
The trade and technological process is understood as a sequence of operations that ensures the process of buying and selling goods and goods movement.The trade and technological process in retail trade is a complex of interrelated trade /commercial/ and technological operations and is the final stage of the entire trade and technological process of product distribution.
The structure of the trade and technological process, the sequence of various operations depends on the degree of economic independence commercial enterprise, the method used to sell goods, the type and size of the store and other factors.
In stores selling non-food products, there are three main schemes of the technological process of sale.
The first includes the acceptance of goods and their supply directly from the receiving area to the trading floor for sale. Such a scheme can be used when using containers-equipment in the trade and technological process. The application of this scheme of the technological process makes it necessary to allocate two functional premises for its implementation: for the acceptance of goods and for their sale.
In the second scheme, the technological process consists of three operations: acceptance, storage of goods and their sale.
The most complex is the third scheme of the technological process, which is used when organizing the sale of goods that require preliminary refinement before serving them on the trading floor (for example, release from factory packaging, ironing, cleaning, etc.). Its use requires the presence of another functional room - a room for preparing goods for sale. In most cases, non-food stores use all three process flow diagrams.
An integral part of any technological process in trade is direct customer service, which is one of its main functions.
The constituent elements of the process of selling goods in non-food stores are divided into:
Basic.
These include:
A) the offer of goods;
b) consultations of buyers;
c) operations for the release of goods;
d) settlement and cash operations.
Auxiliary.
These include:
A) acceptance of goods;
b) placing and stacking them in a warehouse;
c) preparation of goods, workplaces and customer service areas for sale;
d) internal transportation of goods.
Technological process of production
Product quality Catering- set consumer properties food, which determine its suitability to meet the nutritional needs of the population.Aggregate useful properties culinary products are characterized by nutritional value, organoleptic characteristics, digestibility, safety.
Energy value - is characterized by the amount of energy released from food substances in the process of biological oxidation.
Biological value - is determined mainly by the quality of food proteins - digestibility and the degree of balance of the amino acid composition.
Physiological value - the presence of substances that have an active effect on the human body (caffeine, coffee).
Organoleptic indicators (appearance, color, texture, smell, taste) are determined with the help of the sense organs.
Digestibility - the degree to which food components are used by the human body.
Safety is the absence of an unacceptable risk associated with the possibility of harm to human health.
There are the following types of food safety:
Chemical safety is the absence of an unacceptable risk that can be caused by toxic substances to the life and health of consumers.
Toxic substances are nitrates, nitrites, pesticides, antibiotics, dyes and illegal food additives.
Sanitary and hygienic safety - the absence of an unacceptable risk that may arise from microbiological and biological contamination of culinary products.
At the same time, toxic substances (salmonella, staphylococcus) accumulate in the products, which cause poisoning of varying severity.
Radiation safety is the absence of an unacceptable risk that can be caused to life and health by radioactive substances.
Process steps
The 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. The technological process includes a consistent change in size, shape, appearance or internal properties of the subject of production and their control. The objects of labor include blanks and products.Single technological process - A technological process for the manufacture or repair of a product of the same name, size and design, regardless of the type of production Standard technological process - A technological process for the manufacture of a group of products with common design and technological features.
Group technological process - The technological process of manufacturing a group of products with different design, but common technological features.
A technological operation is a complete part of a technological process performed at one workplace.
On the basis of operations, the complexity of manufacturing products is determined and time standards and prices are established; the required number of workers, equipment, fixtures and tools is set; the cost of processing is determined; scheduling of production is carried out and quality control and timing of work is carried out. In addition to technological operations, the technological process in some cases includes auxiliary operations (transport, control, marking, chip removal, etc.) that do not change the size, shape, appearance or properties of the workpiece, but are necessary for the implementation of technological operations.
A technological transition is a complete part of a technological operation performed on one or more surfaces of the workpiece, with one or more simultaneously working tools without changing or with automatic change in the operating modes of the machine. In the case of using conventional metal-cutting machine tools, technological transitions, as a rule, are carried out with unchanged modes of their operation. Elementary transition - part of the technological transition, performed by one tool, over one area of the surface of the workpiece being machined, in one working move without changing the mode of operation of the machine.
Auxiliary transition - a completed part of a technological operation, consisting of human and (or) equipment actions that are not accompanied by a change in the shape, size and surface roughness of the object of labor, but are necessary to perform a technological transition (installation of a workpiece, tool change, etc.).
Billet - an intermediate product of metallurgical production, from which a part is made by changing the shape, size, surface properties and (or) material. Initial billet - Billet before the first technological operation.
A part is a product made of a material that is homogeneous in name and grade without the use of assembly operations (for example, a shaft from a homogeneous piece of metal, a cast body, etc.).
Process safety
The safety of technological processes in accordance with GOST 12.3.002 is ensured by the choice of:Technological process, techniques, modes of operation and maintenance procedures production equipment;
- industrial premises; and sites;
- raw materials, blanks and semi-finished products, as well as methods for their storage and transportation (including finished products and production waste);
- production equipment and its placement, as well as the distribution of functions between a person and equipment in order to limit the severity of labor, etc.
Production processes should not pose a danger to the environment, they should be fire and explosion-proof. All these requirements are laid down during their design and implemented at the stages of organizing and conducting technological processes.
In doing so, it is necessary to provide for the following:
Elimination of direct contact of workers with raw materials, blanks, semi-finished products, finished products and production wastes that have a harmful effect;
- replacement of technological processes and operations associated with the occurrence of hazardous and harmful production factors, processes and operations in which these factors are absent or have a lower intensity;
- replacement of harmful and flammable substances with less harmful and dangerous ones;
- complex mechanization, automation, use of remote control of technological processes and operations in the presence of dangerous and harmful production factors;
- sealing equipment;
- the use of control and process control systems that ensure the protection of workers and emergency shutdown of production equipment;
- timely receipt of information about the occurrence of hazardous and harmful production factors;
- use of means of collective protection of workers;
- rational organization of work and rest in order to prevent monotony and physical inactivity, as well as limit the severity of work.
Safety requirements for the technological process are included in the regulatory and technical and technological documentation.
Despite the wide variety of technological equipment in terms of purpose, design and operation features, it is subject to General requirements safety, formulated in GOST 12.2.003. In accordance with GOST, production equipment must ensure safety during installation, operation, repair, transportation and storage, when used separately or as part of complexes and technological systems.
The equipment is placed in compliance with the current technological, construction, sanitary, fire and other requirements. The convenience and safety of its maintenance, the safety of evacuation of workers in case of emergencies should be ensured, and the impact of hazardous and harmful production factors should be excluded. Passage width. When the equipment is located with the back sides to each other, it should be at least 1 m, when the front and back sides are located to each other - at least 1.5 m, when the workplaces are located opposite each other - at least 3 m. Workplace organized taking into account ergonomic requirements in accordance with GOST 12:2.061.
Production equipment in operation:
Must not pollute environment emissions of harmful substances above the established norms;
- must be fire and explosion proof;
- should not create a hazard as a result of exposure to humidity, solar radiation, mechanical vibrations, high and low pressures and temperatures, aggressive substances and other factors.
Safety requirements are imposed on the equipment during its entire service life.
The safety of production equipment itself must be ensured by the following measures:
The correct choice of operating principles, design schemes, safe structural elements, materials, etc.;
- application in the design of mechanization, automation and remote control;
- application in construction special means protection;
- fulfillment of ergonomic requirements;
- inclusion of safety requirements in technical documentation for installation, operation, repair, transportation and storage.
In accordance with the requirements of the SSBT, safety requirements standards are being developed for all major groups of production equipment. Consider the sections that they include.
Safety requirements for the main structural elements and the control system, due to the features of the purpose, design and operation of this group of production equipment and its components:
Prevention or limitation of the possible impact of hazardous and harmful production factors to regulated levels;
- elimination of causes contributing to the emergence of dangerous and harmful production factors;
- arrangement of controls and other requirements.
The standards for individual groups of production equipment indicate:
Moving, current-carrying and other dangerous parts to be protected;
- permissible values of noise characteristics and vibration indicators, methods for their determination and means of protection against them;
- permissible levels of radiation and methods of their control;
- allowable temperatures of controls and external surfaces of production equipment;
- allowable effort on the controls;
- the presence of protective interlocks, braking devices and other means of protection.
Requirements for the means of protection included in the design, due to the features of the design, placement, control of work and the use of the means in question.
Including:
To protective barriers, screens and means of protection against ultrasound, ionizing and other radiation;
- to the means of removal from the working area of substances with dangerous and harmful properties;
- to protective interlocks;
- means of signaling;
- signal painting of production equipment and its components;
- to warning labels.
Protective fences included in the design of the equipment must comply with GOST 12.2.062. Easily removable guards must be interlocked with the starting devices of the electric motors to turn them off and prevent starting when they are opened or the guards are removed.
Process control
Control of compliance with the technological process, as well as quality control, in general, cannot be limited only to activities QCD controllers or technologists. This work is the paramount task of all production workers, and above all of the workers themselves.In connection with the introduction integrated system quality management in many factories, the control functions performed by worker operators have been expanded.
However, this progressive business may turn out to be ineffective if it is not provided with appropriate organizational and technical training (systematic maintenance of equipment and tooling in good condition, training workers in control methods and providing them with the necessary measuring instruments, compliance with the rules of GOT in the workplace, etc.) .
If for some reason the worker-operator is unable to provide a reliable check of the quality of his work (for example, due to the lack or insufficient accuracy of measuring instruments, the unsuitability of the workplace for quality control, etc.), he is obliged to involve for this OTC workers.
At the same time, it should be noted that the introduction of self-control in the workplace and a system of personal brands does not at all relieve inspectors and other specialists from checking the quality of technological operations.
But at the same time, their importance in the prevention of production defects and the timely transmission of information to workers about the appearance of any errors (symptoms of marriage) and the need to take appropriate measures to prevent them in further work becomes more significant.
This is achieved by the so-called "flying" control, in which QCD employees must systematically carry out random checks of product quality during its manufacture. Thus, the main task of technical control is the prevention of defects, and not their passive accounting.
Process map
A process flow chart is a process document containing a description of the process of manufacturing, assembling or repairing a product (including control and movement) for all operations of one type of work performed in one workshop, in technological sequence indicating data on technological equipment, material and labor standards.It also defines the place of work, the type and size of the material, the main surfaces of the workpiece and its installation, working tools and fixtures, as well as the duration of each operation.
The technological process is developed on the basis of a drawing, which for mass and large-scale production must be made in great detail. With make-to-order production, often only a route workflow is given, listing the operations required for processing or assembly.
ball bearing
The time required for the manufacture of a product in single-piece and small-scale production is set approximately on the basis of timing or accepted standards, and in large-scale and mass production - on the basis of design and technical standards.
Basing is called giving the workpiece or product the required position relative to the selected coordinate system.
A base is a surface, a combination of surfaces, an axis or a point that belongs to a workpiece or product and is used for basing.
By purpose, the bases are divided into design, main, auxiliary, technological and measuring.
The design base is used to determine the position of a part or assembly unit in a product.
The main base is a design base that belongs to a given part or assembly unit and is used to determine its position in the product. For example, the main bases of a shaft assembled with bearings are its bearing journals and a thrust collar or flange.
knee shaft
An auxiliary base is a design base that belongs to a given part or assembly unit and is used to determine the position of the product attached to them. For example, when connecting a shaft to a flanged bushing, the auxiliary base can be the shaft bore diameter, its collar and key.
The technological base is a surface, a combination of surfaces or an axis used to determine the position of a workpiece or product in the manufacturing or repair process. For example, a part base plane and two base holes.
The measuring base is used to determine the relative position of the workpiece or product and measuring instruments.
Types of technological processes
Technological processes according to the level of generalization are divided into two types: single and typical.A single technological process is applicable only for the manufacture of one specific product, and a standard technological process is applicable for the manufacture of a group of similar products.
A single technological process is a process of manufacturing or repairing a product of the same name, size and design, regardless of the type of production. The advantages of a single technological process include, on the one hand, the ability to take into account all the features of a given product, and on the other hand, the most efficient manufacture of a product by taking into account specific production conditions (available technological equipment, fixtures, tooling, workers' qualifications, etc.). ).
Along with the advantages of a single technological process, there are also disadvantages. It takes a lot of time and effort to develop it.
The time spent on the development of a technological process can be many times greater than the time spent on its implementation. If a large number of products are manufactured, then the share of time spent on the development of the technological process per product will be insignificant, but with a small production of products, this share will increase sharply. In this case, an enlarged technological process is developed, for example, only a route description of the technological process is created, which includes a sequence of operations and equipment, but without indications of transitions and process modes. Everything else is left to be decided directly by the worker, who must have the appropriate qualifications. As the volume of manufactured products grows, the development of the technological process is carried out in more detail.
In a single production, the high duration of the development of the technological process often conflicts with the duration of the process itself. The more thoroughly and in detail a single technological process is developed, the more time is required for its development and the higher the qualification of the technologist should be. However, under certain conditions, the time spent on the development of the process becomes much greater than the time spent on its implementation. An illustration of this situation can be the technological process of manufacturing parts on a CNC machine, where its development is distinguished by great care and detail. So, for example, the documentation of the technological process of manufacturing a part on a CNC machine contains a set-up chart, an operational-technical chart, a tool movement scheme, an operational settlement-technical chart, a programming card, drawings of special tools and equipment. All this leads to an increase in the complexity of the development of the operation; for example, only the development of a control program and its debugging for parts of high complexity requires several working days of a programmer technologist, while processing a small batch of such parts can fit into one work shift.
The design of a single technological process is characterized by a large number of possible solutions for each product to be manufactured. Therefore, in the conditions of a single production with a relatively short time allotted for the development of the process, the possibility of reinforcing the decisions made with objective technical and economic calculations is very limited.
In mass production, the high labor intensity of a thorough development of a single technological process turns out to be justified, since its value is incomparably small compared to the labor intensity of manufacturing the entire volume of products of a given name. Justifies itself in mass production and application special equipment, tooling, characterized by high-performance workflows.
Disadvantages of single technology. In mass production, they are manifested in the long duration of the technological preparation of production, due to the need to create special technological means.
The widespread use of a single technology on the scale of the entire machine-building production of the country leads to large losses. The fact is that, on average, manufactured products consist of approximately 70% of general machine-building units and parts that are close in their structural structure. But at thousands of machine-building enterprises they are manufactured according to single technological processes, which differ little in efficiency from each other, but often use original equipment, and in large-scale and mass production - and original technological equipment. At the same time, progressive high-performance solutions developed at any one enterprise and requiring large labor costs are lost in a huge variety of developments and practically do not find application in other enterprises.
All the listed negative aspects of a single technology were the reason for the search for a new type of technology free from these shortcomings. The first step in this direction was the development of a standard technology, when in the 30s of the XX century prof. A. P. Sokolovsky expressed the idea of typification of technological processes.
A typical technological process is characterized by the unity of the content and sequence of most technological operations for a group of products with common design features.
The standard technology is based on the classification of products into classes - subclasses - groups - subgroups - types. A type is a group of similar products, among which a typical representative is selected that has the largest set of properties of products included in this group. A technological process is developed for a typical representative, according to which all products of this type are manufactured. If a particular product lacks a particular characteristic (for example, some kind of surface), when developing a workflow, the corresponding operation is excluded from the standard process.
Thus, the standard process to a certain extent resolves the contradiction between the large time spent on the development of the process and the short time for manufacturing the product, since the time spent on developing the working process for the manufacture of a particular product is sharply reduced. Developing for a group of parts that are close in their own way constructive design, one typical process, it is possible to develop a better process, as it can be designed more time and money. Using a standard process, a working technological process for a part from a group will be developed quickly and efficiently.
Typical processes make it possible to avoid repeated and new developments in the design of working technological processes, as a result of which the work of the technologist is facilitated and the time spent on development is reduced.
An important circumstance: a typical technological process, acquiring universality, at the same time loses its individual features. Indeed, a typical technological process for manufacturing parts is developed for a group of structurally similar parts included in one type. According to this standard process, all the parts of the group are made, despite the fact that they differ from each other in some way. This is the universality of a typical technological process.
The loss of individuality of the standard process lies in the fact that it does not take into account the differences noted above, the specifics of products included in one type. As you know, in each type, a typical part is selected from a group of parts, which differs in the most common structural shapes, dimensions, accuracy requirements, and other quality indicators. A standard part is usually the most complex of all the parts included in this type. Therefore, if a single technological process were developed for each part from this group, then it would be more efficient than a standard process, since it takes into account all the features of the part (in other words, the loss of individuality does not allow the standard process to become optimal for each part of this group) .
The more products in the group differ in their design and quality requirements, the more the typical process differs from the optimal one. This is one of the limitations of expanding a group of products for one standard technological process. As a result, manufactured products have to be divided into more types, which leads to an increase in the number of standard processes and reduces the efficiency of typing.
Generally standard technology promotes:
1) reducing the diversity of technological processes and introducing uniformity in the manufacture of similar products;
2) introduction and dissemination of best practices and achievements of science and technology;
3) simplifying the development of work processes and reducing the time spent on their development;
4) reducing the variety of technological equipment of technological processes;
5) development of new highly efficient technological processes.
The effectiveness of single and standard technologies will be different depending on the type of production. In mass production, it is more efficient to use a single technological process, as it allows you to create an optimal technological process, resulting in a high total economic effect.
As the variety of manufactured products grows, their serial production decreases, the size of batches increases, the loss of time associated with frequent readjustments of technological equipment and tooling. As a result, the efficiency of production decreases, the cost of manufacturing products increases. And the wider the range of products produced and the smaller their serial production, the lower the production efficiency.
Under these conditions, the problem arose of grouping products that are distinguished by the homogeneity of manufacturing technology, which makes it possible to reduce the number of equipment changeovers and increase the size of batches arriving for processing.
As a result of solving this problem, the new kind technologies - group technology, the founder of which is prof. S. P. Mitrofanov.
If standard technology is aimed at reducing the labor intensity of technological preparation of production, increasing the efficiency of technological processes and disseminating progressive solutions, group technology is designed to increase the efficiency of the production process.
Group technological process is the process of manufacturing a group of products with different design, but common technological features.
The batch process has found application in small-scale and serial production. The fundamental essence of group technology lies, first of all, in grouping products into technological groups according to technological similarity. A group technological process is developed for a complex product. Unlike a typical product, a complex product is a "collective" one, often not existing in reality, combining the features of most products included in the group. For a complex product, a technological process is developed and all products of this group, being, as a rule, simpler than a complex product, are manufactured according to this technological process, skipping individual technological transitions. All products assigned to this technological process are manufactured in batches.
As a complex product of a technological group, some product from the group or an artificially created product is used. For example, a complex part is formed as follows: the most complex part is taken, which includes all the surfaces of other parts, and if it does not contain all the surfaces contained in other parts of the group, then the missing surfaces are artificially added to it.
Distinguish group operation and group technological process. A group technological operation is developed to perform technologically homogeneous work in the manufacture of a group of products at a specialized workplace, subject to the possibility of partial adjustment of the technological system. Group technological process is a complex of group technological operations performed at specialized workplaces in the sequence of the technological route of a group of products, elements.
The use of group technology is especially effective when, on its basis, in serial and small-scale production, it is possible to create group in-line or even automatic lines for the manufacture of products or parts of individual groups. The creation of such lines is usually based on a combination of the principles of typification of technological processes and group processing, that is, when a typical route is used (for example, when processing workpieces for individual group operations performed on machines with group settings, and with the widespread use of group changeover devices).
The use of group technology is more effective, the larger the technology group.
When introducing group technology, difficulties arise associated with the organization of large technological groups, not only due to the complexity in building group adjustments and fixtures, but also because of the need to take into account scheduling for the release of products.
Products manufactured according to group technology, although similar, have differences, therefore, with rare exceptions, it is not possible to completely get rid of the readjustment of equipment.
As the range of parts in a group expands, when developing a group setup, its complexity, the number of positions, and the downtime of tool positions increase. This limits the range of parts in the group leads to an increase in the number of groups and, consequently, an increase in the number of group technological processes (operations). Group technology justifies itself under the condition of repeated repetition of the production of this technological group of products. If repeatability is absent or insignificant, then the additional costs of technological preparation, which are much higher compared to a single technology, do not pay off (an example of the effective use of group technology can be aviation industry, where there is a high frequency of groups).
The practice of introducing standard and group technological processes shows that, despite obvious benefits, the share of their implementation is low and a single technology still dominates. One of the main reasons for this is the lack of classification of products into types, groups, which are used in the development of standard and group processes. An analysis of these classifications shows that in both cases, explicitly or implicitly, as hallmarks are not constructive, but technological characteristics. This leads to the fact that at enterprises that differ in the composition of technological means and the qualifications of workers, the same product range will be divided into different groups. On the other hand, it is worth changing the technology and equipment used at the enterprise, as types and groups will have to be changed. To minimize these shortcomings, it is necessary to classify products into groups not by technological, but by design features, which will reduce the variety of standard and group processes and expand their scope.
Summing up the analysis of various types of technological process, the following can be noted:
The use of a single process allows you to develop optimal processes, but this leads to a large investment of time for their development;
- the use of a standard technological process reduces the volume and terms of technological preparation of production, but does not provide optimal process for each part of the same type;
- the use of a group technological process, although it increases the size of the batch, but requires the repeatability of the production of products, which significantly reduces the area of its effective application.
All three types of technology are not flexible, as they do not allow you to change the route if necessary.
One of the main reasons for the shortcomings of all types of technological processes is the description of the product at the geometric level, when the part is represented by a set of elementary geometric surfaces, and the assembly unit is a set of parts as geometric bodies.
This leads to the fact that the technologist, developing the technological process, tends to produce such combinations of surfaces at operations that allow achieving the highest productivity. However, in this case, the bonds between the surfaces are often violated, due to the joint performance of the functions of the part. As a result, firstly, there is a multivariance of the technological process due to a large number combinations of surfaces manufactured at operations, and secondly, due to the manufacture of functionally related surfaces at different operations, complex technological dimensional relationships arise, leading to the need to introduce additional operations.
All this leads to an unreasonable variety of technological processes, an increase in the complexity of their development, causes difficulties in the typification of technological processes and in grouping parts in the development of group processes.
If the part is described by functional blocks in the form of surface modules united by the joint performance of service functions, then the geometric feature becomes secondary, and elementary surfaces are part of the surface modules and are not independent objects in the development of technological processes.
Given the limited range of MPs and their high repeatability, it is possible to significantly reduce the variety of technological operations in terms of the composition of manufactured MPs. As a result, the development of technological processes, their typification and grouping of parts when using group processes will be simplified. All of the above is also true for assembly technological processes, if the assembly unit is considered as a set of connection modules.
In order to realize the above advantages of describing the product as a combination of MP and MS, the construction of the technological process should be considered as a layout of the modules for manufacturing MP (MS) that are part of the part (assembly unit).
In this regard, the process was called a modular technological process, respectively, it can be a single, typical, group process, and is the result of further improvement in the methodology for developing technological processes, starting with the description of the product.
A modular technological process is a technological process built from the modules of the MP or MS manufacturing processes that are part of the manufactured product. The modular technological process is based on the objective existence of MP and MS, which are structural elements of products. A narrow nomenclature and a limited number of characteristics describing them opens the way to the utilization of design solutions for MP, MS, unification of their characteristics and, on this basis, the development of modules for technological support for manufacturing MP and obtaining MS.
The technological support modules include modules of the technological process (MTI) for the manufacture of MPs and the assembly process (MTS) for obtaining MS, modules for technological equipment (MO), tool adjustment (MI), technological bases (MTB), fixtures (MPr) and control and measuring devices (MKI).
Since modular technological support is being developed for standard MP and MS with unified characteristics, it has a high level of generalization, therefore, a wide scope. Having technological support at the modular level, a modular manufacturing process, for example, parts, is built as follows. First, the sequence of formation of all MP parts from the workpiece is determined, then from the data bank they call - i > 1 MTI, MTB, MO, MI, MPR, MKI, necessary for the manufacture of each MP, then MTI are combined into operations.
Modular technological process combines the advantages of single, standard and group technological processes. Indeed, a modular technological process is developed in the same way as a single technological process, taking into account all the features of the product. However, unlike a single process, the complexity of its development is low, since it is built by the method of assembly from the available modules of technological support.
The idea of typing in a modular technological process is implemented at the level of technological support modules, while typing is carried out more efficiently, since MP and MS modules, unlike products, are described by a small number of characteristics.
For example, even a relatively simple part contains a dozen or two surfaces and has a wide variety of design options. At the same time, the requirements for the accuracy and quality of the surface layer of the surfaces of such a part may be different, which further increases its diversity. As a result, for the manufacture of such a multitude of parts, a large number of typical technological processes will be required.
In contrast to a part, an MP of the same name has a smaller number of design options, contains, with rare exceptions, no more than three surfaces, which significantly reduces the variety of MG1 and reduces the number of typical modules of the technological process.
The idea of group technology, which consists in the organization of technological groups from different products, is solved in the best way in the conditions of modular technology. The fact is that, due to the limited range of MP and MS, it is relatively easy to form technological groups even in the conditions of a single production, i.e., the repeatability of manufactured products is not required.
And in conclusion, we note that the modular technological process acquires some flexibility, allowing, within a limited range, to change the sequence of operations. This is explained by the fact that in traditional technological processes, the functionally connected surfaces of the part can be manufactured in different operations. For example, such surfaces of a part as an end face, a hole and a keyway, forming a set of bases (MPB311), can be made in different operations. As a result, complex dimensional relationships arise between operations, which are violated when the sequence of the operation is changed, which can lead to marriage. Therefore, changing the developed route process is unacceptable. In the modular technological process, the functionally connected surfaces of the part are always combined by the corresponding module and are manufactured in one operation. This greatly simplifies the dimensional relationships of the technological process, makes them transparent, which makes it relatively easy to determine the possibility of changing the processing route.
The principles of building modular technological processes make it possible to build machine-building production in a new way, which is based on the through application of the modular principle throughout production chain: product - technological processes - technological systems - organization of the production process.
Design of technological processes
The design of any technological process should be based on three principles: technical, economic and social. In accordance with the first principle, the technological process must ensure the full fulfillment of all the requirements of the working drawing and specifications for the manufacture of a given product. In accordance with the second principle, in the manufacture of a product, the required labor productivity and the lowest cost should be ensured.In accordance with the third principle, the technological process must comply with the requirements of safety and industrial sanitation according to the system of labor safety standards (SSBT). Environmental factors must be taken into account. Process design aims to give detailed description manufacturing processes of products with the necessary technical and economic calculations and justification of the chosen option, since technological processes are characterized by their multivariance.
For example, the surfaces of the same part can be machined in different sequences. different methods; the same assembly unit, as a rule, can be assembled using different methods to achieve accuracy. Of several options technological process of manufacturing the same product, equivalent in terms of technical principle design, choose the most efficient and cost-effective option.
With equal productivity of the compared options, the most cost-effective one is chosen, and with equal profitability, the most productive one. The efficiency and profitability of the designed process is determined by all the elements of which they are composed. The tasks of technological design are to determine the conditions for manufacturing products, determine the type of production, types of initial blanks, design a technological processing route, identify the necessary means of production and the procedure for their use, determine the cost and labor intensity of manufacturing products, determine the initial data for scheduling, for organization of technical control, determination of the composition work force.
The solution of design problems depends on a large number of factors related to the official purpose of the product, its design and technological parameters and the state of production. When solving these problems, optimization of technological processes should be carried out, which consists in ensuring the release of the required number of products of a given quality at the lowest possible cost of production with the best performance of all elements of the processes and the least time. Optimization is a time-consuming process and is most effectively solved using computer science.
Technological processes are developed in the design of new, reconstruction of existing enterprises, as well as in the organization of the production of new products at existing enterprises. At the same time, the accepted options are the basis for all technical and economic calculations and design decisions. The level of development of technological processes determines the level of work of the enterprise. In addition, technological processes are developed and adjusted in the conditions of existing enterprises in the production of mastered products. This is caused by continuous constructive improvements in products, the need for systematic use and implementation of the achievements of science and technology in existing production through the development and implementation of organizational and technical measures, the need to eliminate bottlenecks in production.
Execution of a workflow
Depending on the configuration of the part, the grade of the material being processed, the output of the product and the specific production conditions, the technological process can be divided into more or less number of operations.It uses two principles:
1. Differentiation, when the number of surfaces to be machined in one operation decreases, while the number of operations increases. The limit of differentiation is when one simplest surface is processed in one operation.
The advantages of the differentiation principle are the possibility of using methods of various physical nature for processing (for example, electric spark piercing of shaped holes), special high-performance equipment (for example, plunge grinding machines), optimal processing modes for each surface, etc. Differentiation of technological processes is used both in the mass production of parts of a simple configuration (for example, piston pins of an internal combustion engine) and in the single-piece production of parts with complex profiles (for example, turbine blades of a gas turbine engine).
2. Concentration, when as many surfaces as possible are processed in one operation, while the number of operations in the technological process decreases. The concentration limit is when the entire technological process degenerates into one operation.
The advantages of the principle of concentration are: increasing the accuracy of the relative position of the treated surfaces; processing productivity increases many times due to the use of multi-spindle, multi-support, multi-place machines; simplification of the organization of production, since planning and accounting are carried out according to operations, and their number is reduced; reduction in the number of workpiece installations, which especially reduces the time spent on transportation in the manufacture of heavy and large-sized parts; time and costs for production preparation are reduced due to a decrease in the range of devices for installing and fixing workpieces.
Technological equipment is the production tools necessary to perform a certain part of the technological process, in which materials, semi-finished products and blanks are placed and fixed, means of influencing them and, if necessary, energy sources (metal-cutting machine tools for universal and special purposes, presses, hammers, foundry machines, furnaces, test benches, etc.).
Technological equipment is called production tools added to technological equipment and necessary to perform a certain part of the technological process (tools, fixtures, means of mechanization and automation of production processes). Tools can be working and control (measuring). The working tool is used for direct impact on the material being processed in order to convert it into finished parts or assembly units (the categories of workers include cutting tools used in processing on metal-cutting machines (cutters, drills, cutters, broaches, etc.), dies for cold sheet and bulk hot stamping, casting molds, riveting, welding tools, etc.). The measuring tool is used to measure the geometric parameters of manufactured products (universal tools for measuring linear and angular dimensions (rulers, calipers, micrometers, goniometers) and special ones (gauges, templates, etc.)). Devices are used to install and fix workpieces in a given position in technological equipment during the manufacture of parts or to install and fix parts in an assembly position during the manufacture of assembly units. Means of mechanization and automation are used to mechanize and automate production processes in order to facilitate and increase the productivity of performers.
Technological equipment, technological equipment and means of mechanization and automation of production processes are collectively called technological equipment. The type and quantity of technological equipment used is determined by the technological process for the manufacture of one or another structural element of the aircraft.
Technological equipment and tooling for practical use are being adjusted. Adjustment is the preparation of technological equipment and technological equipment for a specific technological operation (installation of a fixture on the machine, switching the speed and feed of the machine, installing a stamp and setting up the press, regulating and setting the set temperature in the furnace during heat treatment, etc.). The term “adjustment” is also used, which means additional adjustment of technological equipment and (or) tooling in the process of operation to restore the values of parameters achieved during adjustment.
Process characteristic
In public catering, three forms of organization of production are distinguished:1) production of products from the processing of raw materials to cooking and its sale;
2) preparation of products from semi-finished products and their sale;
3) organization of food consumption with little preparation for sale. In other words, according to the nature of the organization of production, there are enterprises with a complete and incomplete technological cycle.
Raw materials are products from which culinary products are produced according to the scheme: processing of raw materials - cooking - sale. Semi-finished products are products that have undergone primary processing at procurement enterprises and have varying degrees of readiness. Finished products- dishes and culinary products ready for sale.
The products produced by public catering enterprises are perishable and require quick sale. Various products and raw materials used for cooking and culinary products, also do not withstand long periods of storage. In this regard, public catering enterprises should ensure the maximum reduction in the periods of storage, processing of raw materials and the sale of finished culinary products. Therefore, the commercial success of an enterprise and the sanitary safety of its products directly depend on how correctly and accurately the order is drawn up and the work of suppliers of semi-finished products and raw materials is coordinated. In order to correctly determine the volume production program and range of products, it is necessary to take into account the demand of consumers for different kinds dishes and culinary products.
Of great importance for the proper organization of the technological process at catering establishments are the observance by cooks of the norms for investing raw materials in accordance with approved recipes, the organoleptic evaluation and rejection of ready-made dishes and culinary products.
One of the main factors that determine the characteristics of the production process of public catering enterprises is their transfer to work with semi-finished products. Centralized and integrated supply of enterprises with semi-finished products creates an opportunity for the most rational use technological equipment, increasing labor productivity, narrower specialization of workers, can reduce the cooking process, reduce production costs.
A shopless structure of production is being established at enterprises with a small volume of production or working on semi-finished products. Everybody is here production processes is carried out by one or more teams that report to the production manager. Such an organization of labor makes it possible to use chefs more effectively, to practice combining professions, etc.
All production facilities of public catering enterprises are usually divided into procurement, pre-cooking, auxiliary and auxiliary. Procurement - these are vegetable, meat, fish and poultry shops on large enterprises, at enterprises of small capacity - vegetable and meat and fish shops. The pre-cooking workshops include hot and cold workshops, auxiliary workshops for the production of soft drinks (at large enterprises), and auxiliary workshops for distributing, bread slicers, and pan washers.
The main conditions for the proper organization of the technological process of cooking: the optimal area of production premises, their rational placement and provision of production workshops necessary equipment.
As the practice of work of domestic and foreign enterprises has shown, it is most appropriate for modern enterprises catering linear principle of equipment placement. The lines are completed from separate sections, specialized in the performance of certain technological operations. All sections must be the same in height and width (depth), and their length must be a multiple of a certain value (modulus) established for all sections. Equipment designed for completing such lines is called sectional modulated equipment.
Sanitary standards for premises, as well as the existence of conditions that ensure compliance with labor protection laws for workers, is something that must be observed both in large state or joint-stock companies and in private enterprises.
In industrial premises of catering establishments, ceilings must have a height of at least 3–3.3 m. Glue paint is used for walls light shades, and wall panels to a height of 1.7 m are lined with light-colored ceramic tiles that can be easily sanitized.
Floors are covered with tiles and other waterproof materials that are easy to clean.
While creating necessary conditions for the work of workers, the temperature regime in the production premises is of considerable importance. Thus, in the blank shops the air temperature should not exceed 16–18°С, in the hot shop – 22–25°С. Special ventilation systems must ensure the removal of superheated air, vapors and exhaust gases. To do this, install mechanical exhaust and supply and exhaust ventilation. During exhaust ventilation, stale air is removed from the premises by a fan, and fresh air enters through the pores of the walls or specially left channels and openings in the walls and coatings, as well as through the ventilation grilles. For supply and exhaust ventilation, separate fans are installed in the premises, causing movement and air exchange, or ventilation supply and exhaust installations are equipped when air enters and is removed through channels made of tin, brick or plastic, and air flow is regulated using gratings.
To create and maintain an artificial microclimate and the specified temperature, humidity, air mobility and purity in industrial premises, automatic air conditioning units are used.
Industrial premises must be equipped with cold, hot water and sewerage. In the event of a lack of hot water, backup water heaters should be installed. Water is supplied to bathtubs, sinks, as well as stoves, boilers and other equipment. The sewerage system provides for quick removal Wastewater. Baths, sinks, washbasins are equipped with hydraulic seals that prevent the penetration of sewer odors.
Use of technological processes
The Austrian scientist J. Schumpeter (1911), who worked at Harvard University in the USA, suggested that new combinations of production factors become the impetus for development.Schumpeter identified 5 new combinations of factors:
1. use new technology, new technological processes;
2. introduction of products with new properties;
3. use of new raw materials;
4. changes in the organization of production and its logistics;
5. the emergence of new markets.
New combinations of factors of production are called innovations (innovations).
Schumpeter expressed an idea that still influences economic thought: capitalism is by nature a form of economic change and can never be stationary. The main impetus that starts the engine of capitalism comes from new consumer goods, new modes of production and distribution, new markets, new ways of organizing production, which the capitalist enterprise creates. This process of creative destruction is a factor that touches the essence of capitalism.
In the fundamental work "Business Cycles" (1939), Schumpeter proposed three types of cycles. Each large cycle of the conjuncture includes several medium cycles, and each medium cycle includes several short ones.
Long waves are cycles with a period of 55 years, first discovered by N.D. Kondratiev. Medium cycles - 10 years - are associated with the replacement of the active part of capital in the form of machine tools, Vehicle. Short cycles (about 2 years) are extended by Schumpeter to market changes in relation to certain types of products (modifications).
Economists are now convinced that over the past 250 years, waves of major innovations have occurred more or less regularly, with a cycle of approximately fifty years. In the first few years of the cycle, new technological potential is accumulated. Then the wave of innovations is gaining the greatest strength. Then, during commercial exploitation, the pace of events gradually slows down.
Thus, since the Industrial Revolution, historical waves of intense technological change can be distinguished, characterized by opportunities for rapid economic growth and radical social transformation.
The cause of dynamic change, according to Schumpeter, is the intrusion of the innovator-entrepreneur who needs financial resources for innovation. Therefore, investment is an integral part of innovation activities.
The first wave, which was based on new technologies in the textile industry, using the possibilities of coal and steam, covers the period from 1790 to 1840.
The second wave (1840-1890) is directly related to the development of railway transport and the mechanization of production.
The third wave (1890-1940) was based on the power industry and advances in chemistry.
The fourth wave (since 1940) is associated with the rapid development of electronics, computer technology, and the dominance of mass production.
According to this theory, the world is currently experiencing the fifth wave of technological changes associated with the rapid development of information and telecommunications technologies. Researchers believe that biotechnology will become an important component of the fifth wave.
In accordance with the concept of wave economic activity, periods of economic growth are replaced by recessions and depressions. The first wave of the late 18th century was followed by a period of recession, the second wave (Victorian era) was followed by a deep recession, the third wave at the end of the 19th century ended with the Great Depression, the fourth wave of economic growth after World War II was followed by a crisis accompanied by high unemployment .
Economists have differing views on the length of the waves, the contraction of cycles, whether the fifth and subsequent waves will alternate with the same severe drops as in the past. Yet most of the leading economists of the century, from Keynes to Samuelson, believe in waves of economic activity generated by changes in investment behavior in conjunction with technological change.
Complex technological process
By the nature of the production object, simple and complex production processes are distinguished.A simple process is a process consisting of sequentially performed operations (manufacturing of one part, a batch of identical parts, a group of different parts that have technological similarities and are processed at the same workplace, section, line). The order of operations in this case is determined by the manufacturing technology of the part.
A complex process is a process consisting of sequential and parallel operations. For example, the manufacture of an assembly unit consisting of several parts, the manufacture of a product that includes a certain number of parts and assembly units. The structure of a complex process depends not only on the composition of the manufacturing and assembly processes, but also on the order in which they are performed, which depends on the design of the assembly unit or product.
The concept of a complex technological process can be found in R 50-601-20-91 "RECOMMENDATIONS for assessing the accuracy and stability of technological processes (equipment)".
Complex technological processes have such a property as emergence (the properties of a complex process are not a simple sum of the properties of its constituent elements).
Lecture 2
Plan
1. The structure of the technological process.
2. Elements of the technological operation and characteristics of the technological process.
3. Technological characteristics of various types of production.
1. The structure of the technological process (according to GOST 3.1109–82)
Manufacturing process called the totality of all the actions of people and tools of production necessary for the manufacture or repair of products manufactured at a given enterprise.
Technological process- a part of the production process that contains purposeful actions to change (or determine) the state of the object of labor. There are technological processes for manufacturing a product or part of it, obtaining a workpiece, casting, heat treatment, electrophysical processing, electrochemical processing, assembly, product quality control, repair, etc.
At processing a given change in the shape, dimensions, surface roughness or properties of the workpiece is carried out, and when assembly- the formation of detachable or permanent connections of the components of the workpiece or product.
Apart from main technological processes manufacturing processes include support processes– transportation, warehousing, accounting and reporting.
The technological process consists of operations.
Technological operation- a complete part of the technological process, performed at one workplace.
Workplace- part of the production area of the workshop, on which one or more performers of the work are located, a serviced unit of technological equipment or part of the conveyor, as well as equipment and objects of labor.
An operation is the basic unit of production planning. The approach to the operation as a planning unit allows you to understand many controversial cases where it is not clear whether a given set of actions should be considered as one or more operations.
Example 1
Suppose that when turning a batch of stepped rollers, for all blanks, one neck is first turned, then the second, etc. In this case, the processing of each stage can be considered as a complete part of the technological process, constituting one operation. For each of these operations, a separate order can be issued. However, often to simplify planning and reporting, one general work order is issued for turning rollers, which in this case should be considered as one concentrated operation.
Example 2
In heavy engineering, often at one workplace with the help of portable various machine tools various workers are processing various surfaces of the same workpiece.
In such cases, the work is divided into operations, each of which is performed using a specific machine. If the machines work sequentially and are serviced by one team of workers, then it is possible to combine these operations into one.
Example 3
The worker who serves an autoline of several machines, one order is issued. Therefore, the autoline should be considered one workplace, where one operation is performed.
2. Elements of the technological operation
and characteristics of the technological process
setup- part of the technological operation, performed with the unchanged fixing of the workpiece being processed or the assembled assembly unit. For example, turning two steps of a roller can be done not in two operations, but in one, which has two settings (Fig. 2.1). Processing is carried out on tuned equipment with a rotary tool holder.
Fig.2.1. Roll processing in one operation in two installations
Position- a fixed position occupied by a low-mounted workpiece or an assembled assembly unit together with a fixture relative to a tool or a fixed part of the equipment when performing a certain part of the operation.
For example, the operation - milling four sides of a square contains positions (Fig. 2.2, a).
Multi-position processing is typical for modular machines of multi-spindle automatic and semi-automatic lathes.
For example, the processing of holes in a body part can be performed on an aggregate machine and include 4 positions (Fig. 2.2, b)
Positional machining reduces workpiece set-up time and generally improves productivity.
Rice. 2.2. Positional processing
Technological transition called the completed part of the technological operation, performed by the same means of technological equipment under constant technological conditions and installation.
Auxiliary transition called the completed part of the technological operation, consisting of human actions and equipment that are not accompanied by a change in the properties of the objects of labor, but are necessary to complete the technological transition. Examples of auxiliary transitions are work clamping, tool change, etc.
working stroke- the completed part of the technological transition, consisting of a single movement of the tool relative to the workpiece, accompanied by a change in the shape, dimensions, surface quality or properties of the workpiece.
Auxiliary move- the completed part of the technological transition, consisting of a single movement of the tool relative to the workpiece and necessary for the preparation of the working stroke.
The cycle of the technological operation and the release cycle are the main characteristics of the biological process.
Technological operation cycle- the interval of calendar time from the beginning to the end of a periodically repeating technological operation, regardless of the number of simultaneously manufactured or repaired products.
Release stroke- an interval of time through which the release of products or blanks of certain names, sizes and designs is periodically performed.
3. Technological characteristic
various types of production
Depending on the breadth of the nomenclature, stability and output of products, single, serial and mass production are distinguished.
Single production characterized by a wide range of products and a small volume of output. Examples of products made V single production, are unique machine tools, large turbines, prototypes of machines.
Mass production It is characterized by a limited range of products manufactured in repetitive batches and a relatively large output. Depending on the number of products in a batch (series) and the value of the coefficient of consolidation of operations, small-, medium- and large-scale production is distinguished (Table 2.1).
Table 2.1
Characteristics of mass production
Transaction consolidation ratio- the ratio of the number of all various technological operations performed during the month to the number of jobs.
Series volume- this is the total number of products of certain names, size and design, manufactured or repaired according to unchangeable design documentation.
production batch- a group of workpieces of the same name, size and design, launched into processing simultaneously or continuously for a certain period of time.
Operational batch - a production batch or part of it that enters the workplace to perform a technological operation.
Examples of serial products are universal machines, some pumps, motors.
Mass production characterized by a narrow range and a large volume of products produced continuously for a long time. In mass production, there is usually only one repetitive operation in a workbench. This is how rolling bearings, watches, cars are made.
Different types of production are characterized by different depth of development of technological processes, different documentation, different ways of obtaining blanks, cost, productivity and etc. In particular, in mass production, the highest labor productivity and the lowest cost of production are ensured, the most accurate blanks are used, the documentation is developed in great detail, etc.
As for the organization of production, there are two types of it: in-line and non-in-line. Under the flow type of organization is understood such a type , in which the blank parts and assembled products in the process of their production are in motion, and the latter with a constant tact value. This means that the workpiece received for the first operation is immediately after the end of the operation, it is transferred to the second, after the end of the second - to the third, etc. until the last operation, after which the finished part is immediately fed to the assembly. The waiting time of the workpiece between operations in such cases is equal to or a multiple of the cycle. Finished parts are delivered to the assembly at regular intervals.
An inaccurate type of organization of the production process is understood as such a type in which blanks, parts or assembled products in the process of their production are in motion with different durations of operations and sojourn between them, as a result of which the process is carried out with a changing tact value.
The in-line type of organization of the production process can primarily be used in mass production. Repetitive production, especially with large batch sizes, can also be organized using the in-line view. Distinctive feature Such production is its periodicity in time due to the frequency of launching batches, so it is called variable-flow (group) production. Variable-flow production is most often used for the manufacture of products that are close in function and, consequently, in technological processes.
Technological operation called the finished part of the technological process, performed at one workplace. Operation is the main element production planning and accounting.
This part of the process is performed:
- over a certain workpiece;
- one or a group of workers;
- continuously;
- at one workplace.
The operation can be performed on a separate technological equipment (machine) in normal production or on automatic line, which is a complex of technological equipment. Such equipment is connected by a single transport system with technological equipment and unified system management and control.
The main elements of the technological operation:
1. Installation - part of the technological operation, which is performed with the unchanged fixing of the workpieces or assembled assembly units.
2. Position - a fixed position occupied by an invariably fixed workpiece or an assembled assembly unit together with a fixture relative to a tool or a fixed part of the equipment to perform a certain part of the operation.
3. Technological transition- a completed part of the technological operation, performed by the same means of technological equipment under constant technological conditions and installation.
4. Working stroke - a completed part of the technological transition, consisting of a single movement of the tool relative to the workpiece, accompanied by a change in the shape, dimensions, quality and properties of the surface to be machined.
5. Auxiliary transition- a completed part of a technological operation, consisting of human and (or) equipment actions that are not accompanied by a change in the shape, size, quality and properties of the treated surfaces, but are necessary to complete the technological transition.
6. Auxiliary move- the completed part of the technological transition, consisting of a single movement of the tool relative to the workpiece of the part, which is not accompanied by a change in the shape, size, quality and properties of the surface of the workpiece, and is necessary to complete the working stroke.
7. Adjustment - preparation of technological equipment and tooling for the execution of a technological operation. Adjustment includes the installation of a fixture on the machine, alignment with the size of the cutting tool, etc.
8. Adjustment - additional adjustment of technological equipment or technological equipment when performing a technological operation in order to restore the parameters achieved during adjustment.
9. Technological equipment- these are the means of technological equipment, in which, in order to perform a certain part of the technological process, materials or workpieces are placed, means of influencing them, as well as technological equipment.
10. Technological equipment- means of technological equipment that complement the technological equipment to perform a certain part of the technological process.
