15.1.3. Manufacturing process
The production process is the totality of the actions of workers and tools of production necessary to manufacture or repair manufactured products.
A part of the production process, which includes actions to change and subsequently determine the state of the object of production, is called a technological process, which consists of technological, transport and control operations.
Technology (from the Greek techne - art, skill, skill and λογος - learning) is a set of methods and tools for achieving the desired result; a way of transformation of a substance, energy, information in the process of manufacturing products, processing and processing materials, assembly of finished products, quality control, management. It is developed by engineers-technologists, programmers and other specialists of the enterprise, working in the relevant fields.
Technology combines methods, techniques, operating mode, sequence of operations and procedures, it is closely related to the tools, equipment, tools, materials used. As a production process for the production of goods, it is described in the technological instruction.
The nature of the technological process, the equipment, tools and devices used depends on the scale of production, which determines the type of production.
The technological process of production is a set of operations that are designed to preserve the useful properties of the raw materials and raw materials, optimize the composition, structure, eliminate the negative properties, form the finished product. As part of the technological process, raw materials, technological raw materials, materials and semi-finished products obtained from it are subjected to various methods of technological processing (mechanical, chemical, thermal, biochemical, etc.).
Type of production - the classification category of production, distinguished by the latitude of the nomenclature, regularity, stability and volume of output. Depending on the volume and specialization, three types of production are identified: individual, serial and mass.
Individual production is characterized by the release of a small number of products, often their re-release is not foreseen. An enterprise with individual production should have a universal equipment that allows to apply different types of processing. The technological process of such an enterprise is the most difficult.
Individual production is used in the manufacture of clothing, jewelry, artistic and decorative products and furniture.
Serial production is characterized by the release of goods in batches (series) with a possible re-release. Depending on the size of the series, small-, medium- and large-scale production is distinguished. During mass production, the equipment is used much better and the productivity of labor is higher than with the individual. Serially produced vehicles, sporting goods for professional athletes, clothing and footwear.Mass production is characterized by the release of a large number of products continuously for a long time without changing their design, the mechanization of processing processes, the specialization of equipment, the wide interchangeability of parts and assembly units.
Technological processes are divided into types - single, typical, group.
Single Process is the production or repair of a product of one name, regardless of the type of production; type - manufacturing of a group of products with common design and technological features; group - the production of a group of products with different structural, but common technological features.
There are three stages of the technological process: preparatory, main and final.
Preparatory stage - is a set of operations for preparing the main and auxiliary raw materials and components for processing or assembling. Mainly - this is grinding, cutting, washing, cutting, cutting, sorting, i.e. operations of mechanical and hydromechanical processing.
The main stage is a complex of operations for processing raw materials (materials, semi-finished products) or assembling components to produce finished products. This stage is of decisive importance for the formation of quality of finished products at the production stage and includes a variety of technological operations: dosing and mixing of components, thermal, mechanical, electrical processing.
The final stage is a set of operations for processing finished products in order to give it a presentation, improve storage and confirm compliance with established requirements. The initial properties of the products do not change here, as a new quality of the finished product or product has already been formed. All operations of this stage are aimed at additional product quality improvements or for final quality control.
The above diagram is generalized, so consider a few specific examples.
The technological process for the production of furniture from solid wood consists of the following operations: 1) drying or drying of solid wood; 2) cutting wood, wood and facing materials; 3) the plastification and bending of massive wood; 4) primary mechanical processing of wood, wood and facing materials; 5) gluing and lining wood and wood materials; 6) re-machining of wood and wood materials; 7) finishing of products (assembly units) from wood and wood materials; 8) acquisition, packaging, assembly of products from parts and assembly units. Violation of the technological process of production when processing and obtaining materials and finished products causes the appearance of defects.
During the production of non-food products, various technological operations are used. For example, in the manufacture of steels, mechanical, thermal, physicochemical treatment is used, which improves their appearance, structure, affects the quality level of the future product.
Machining provides surface hardening of the material by plastic deformation. The most commonly used shot blasting and treatment with rollers or balls.
Heat treatment (annealing, hardening, tempering) improves the mechanical properties of the material. Annealing consists in heating the steel to a certain temperature, holding at this temperature and slowly cooling. It is carried out to reduce hardness and improve workability, change the shape and size of the grain, equalize the chemical composition, relieve internal stresses.
Hardening is the heating of the material to a certain temperature, aging and subsequent rapid cooling, resulting in increased hardness and strength, but reduced viscosity and ductility. The listed methods of processing are used in the production of silicate products made of metals and alloys. The release consists in heating the material to a certain temperature, holding and cooling. It is used in the production of steels. The purpose of tempering is to obtain a more equilibrium structure than martensite, to remove internal stresses, increase viscosity and ductility. There are low, medium and high holidays.
The relationship between structure and properties can be demonstrated by the example of steels.Tempering and tempering of steel, carried out at different temperatures, change the structure and mechanical properties: ultimate strength, relative constriction and elongation to failure (Figure 15.5).
Physical-chemical treatment is designed to change the chemical composition, structure and properties of the surface of materials, in particular steels. It includes cementation, nitriding, cyanidation, etc. These methods increase the hardness and wear resistance of the surface of parts while maintaining the viscous core. Cementation is the process of saturation of the surface layer of steel parts with carbon by heating the steel parts at 880-950 ° C in a carbon-containing medium (carburettor). Nitriding is the saturation of the steel surface with nitrogen. At the same time, not only hardness and wear resistance increase, but also corrosion resistance. Cyanidation (nitrocarburization) - simultaneous saturation of the surface with carbon and nitrogen.
Fig. 15.5. Dependence of mechanical properties on the microstructure of hardened and tempered steel:
σв - the ultimate strength of steel; ψ is the relative narrowing of the sample; ε is the relative elongation of the sample; HB - Brinell hardness
In the production of food products, special technological operations that affect quality are also used. From the whole variety of processing methods, we briefly review the most well-known and common ones, united by the common name "canning", which allow to increase the storability and change the taste of the products. With the help of publicly available even in the everyday life of canning methods, it is possible to produce various products on the basis of one or several kinds of agricultural raw materials.
The methods of canning are divided into physical, physicochemical, chemical and biochemical methods.Physical canning methods are based on lowering temperatures (cooling, freezing) or increasing them (pasteurization, sterilization).
Cooling is the processing and storage of products at a temperature close to 0 ° C; at this temperature their taste and food qualities are almost completely preserved. In the cooled state they store fruits, vegetables, cheeses, meat, etc.
Freezing is the temperature drop of the product to -6 ° C and below. When freezing, the development of almost all microorganisms ceases, but bacteria spores persist and can multiply rapidly with increasing temperature. Freeze meat, fish, fruits, vegetables, etc. According to the taste and nutritional properties of frozen foods inferior to chilled.
Pasteurization - is the heating of the product (meat, milk, beer, juices, jam) to a temperature of 60-98 ° C. The nutritional value of such products is almost unchanged. When pasteurized, bacteria spores do not perish.Sterilization is the process of heating and holding a hermetically sealed product at temperatures above 100 ° C, in which microorganisms and their spores are completely destroyed. Sterilization significantly increases the shelf life of food, but it entails complex changes in products, and overall their biological value is reduced. This method is used in the manufacture of vegetable, meat, fish, dairy canned, etc.
Mechanical filtration is the purification of liquid products with the help of porous filters.
The physical and chemical methods of preservation include: drying, canning salt and sugar.Drying is based on the removal of water from the products, resulting in unfavorable conditions for the life of microorganisms. There is a natural, artificial drying of products, as well as drying by sublimation. Preservation of table salt and sugar is based on an increase in the osmotic pressure of the medium, as a result of which the vital activity of most microorganisms is suppressed. Chemical and biochemical methods of preservation are based on the use of chemicals introduced into products or formed in products as a result of biochemical processes (lactic acid, ethyl alcohol). Thus, lactic acid is formed as a result of lactic acid fermentation of sugars of the product and has a preservative effect.
When preserving antiseptic fruit semi-finished products use sulfurous anhydride: fruit and vegetable juices, cheeses, margarine - sorbic acid. It should be noted that these substances are unsafe for human health.
Smoking is a combined method of preserving, as it is based on the action of several factors (high temperature, the introduction of a preservative, etc.). Smoking is hot (at a smoke temperature above 80 ° C) and cold (-20 to -40 ° C). With this method, smoking liquids and electric smoking can be used.
The preservation of the quality of the goods is strongly influenced by the conditions of its storage and transportation in production, in trade and at the consumer.
Also We Can Offer!
- Argumentative essay
- Best college essays
- Buy custom essays online
- Buy essay online
- Cheap essay
- Cheap essay writing service
- Cheap writing service
- College essay
- College essay introduction
- College essay writing service
- Compare and contrast essay
- Custom essay
- Custom essay writing service
- Custom essays writing services
- Death penalty essay
- Do my essay
- Essay about love
- Essay about yourself
- Essay help
- Essay writing help
- Essay writing service reviews
- Essays online
- Fast food essay
- George orwell essays
- Human rights essay
- Narrative essay
- Pay to write essay
- Personal essay for college
- Personal narrative essay
- Persuasive writing
- Write my essay
- Write my essay for me cheap
- Writing a scholarship essay