ВКР 14.06.2017 (1215374), страница 11
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1.1. The concept and structure of the production process at the enterprise.
The production and economic activities of any enterprise are aimed at manufacturing the certain types of products. The basis of the enterprise production activity is production process. The production process is the totality of all the actions of people and instruments of labor that are necessary for the given enterprise to manufacture products. The basis of the production process is the technological process.
Technological process is a part of the production process containing purposeful actions to change and (or) determine the state of the subject of labor. The final part of the technological process performed in one workplace by one or several workers is called a technological operation. Basic or technological operations are actually directed at the change of the subject of labor (change in form, molecular composition, state, appearance, and size). In addition to the main technological operations, the manufacturing process of the prime products includes a number of auxiliary operations (transportation, control, product assorting, etc.) whose purpose is to facilitate the implementation of major operations. The production process consists of labor and automatic processes as well as natural processes that do not usually require labor costs (for example, the time for cooling castings, drying after coating the surface with varnish). At the enterprises which manufacture the compound products the production processes are widely different. In order to organize them rationally, it is necessary to classify the production processes based on the most important characteristics.
Classification of the enterprise production process
Depending on the purpose, the production processes are divided into main, auxiliary, and servicing.
The main production processes are designed to directly change the shape or state of the product. The totality of the main production processes forms the core production which can consist of the three phases (stages): procurement, processing, and assembly. Phase (stage) is a set of works the performance of which characterizes completion of the certain part of the production process and is it is connected with transfer of the subject of labor from one qualitative state to another. The procuring phase includes the processes of obtaining blanks: the production of castings, stamping of blanks, etc. The processing phase includes the processes of converting blanks into finished parts: mechanical processing, heat treatment, electrochemical, and other types of processing. The assembly phase includes assembling the elements and finished products, classification of products by parameters, and testing.
The secondary production processes ensure uninterrupted flow of the main processes; as a result, there become available the products that are used at the enterprise in the main production (manufacture and repair of tools and bagging materials, repair of equipment, generation of all types of energy, steam, distilled water, and packaging).
The server production processes provide the main and secondary processes with the services which are necessary for their normal functioning (transport, storage, etc.).
The main, secondary, and server production processes have the specific features and different development tendencies related to them.
According to the degree of automation (depending on the means of labor used), the manual, mechanized (machine-manual and machine), computer-aided and automated production processes are distinguished. Manual (non-mechanized) operations are performed by workers without the aid of mechanisms, for example, locksmithing, manual marking of the workpiece, etc. Machine-manual operations are performed with machines and a mechanized tool with the continuous participation of the worker (soldering the semiconductor device with a mechanized device, marking the device with the simplest marking machine tool, etc.).
Machine operations are performed on machines, units, and installations with limited participation of a worker: the worker fixes and removes a stock item, starts and stops a machine (welding on machine tools, product machining, and others.). The use of machine processes allows organizing multi-machine maintenance.
Computer-aided production processes are partially performed without a worker who can function only as an observer, for example, the work on a semi-automatic machine. Automatic processes completely free a worker from performing operations leaving for him the functions of monitoring the production progress, loading blanks, and unloading finished parts.
By the flowing nature of the production processes, they are divided into continuous and periodic.
In the continuous processes, technological operations are performed without interruptions in the course of the production process, i.e., the technological process is continuous. In the periodic processes, the performance of technological operations is interrupted by transport or secondary operations, i.e. all operations proceed consecutively. The continuous processes have great advantages over the periodic ones: the time of production is reduced, equipment is maximally used through time, there appears the possibility of complex mechanization and automation of production; and the quality of products improves due to the stabilization of technological regimes, etc. All this leads to an increase in labor productivity and a decrease in the cost of production.
Depending on the breadth of nomenclature, regularity, stability, and product output, the production is divided into three groups - single, serial, and mass.
Single-piece production is characterized by a wide range of products and a low output of identical products. Samples either do not repeat, or repeat irregularly. The places of work do not have the comprehensive specialization. The single-piece production is characterized by the presence of considerablely unfinished production, the lack of fixing the operations in the workplaces, the use of unique equipment, frequent adjustment of equipment, high qualification of workers, significant specific weight of manual operations, the overall high labor intensity of products and a long cycle of their manufacture, and high production costs. A variety of nomenclature makes the single-piece production more mobile and adapted to the conditions of demand fluctuatins for the finished products.
Batch production is characterized by manufacturing a limited range of products. The lots (lots) of products repeat at regular intervals. Depending on the volume of the batch, the small-batch, medium-series, and large-scale production works are distinguished. The batch production allows specializing individual workplaces for performing similar technological operations. The scale of production costs is reduced through specialization of workplaces, widespread use of labor of medium-skill workers, the effective use of equipment and production facilities, and a reduction in wage costs compared to unit production and wages expenses.
The products of the batch production are the standard products: for example, machinery of the established type is usually produced in larger quantities (metal-cutting machines, pumps, compressors, equipment for chemical and food industry).
Mass production is characterized by the manufacture of certain types of products in large quantities at highly specialized workplaces for an extended period. Mechanization and automation of mass production can significantly reduce the proportion of manual labor. Mass production is characterized by a constant range of manufactured products, specialization of workplaces for performance of the permanently fixed operation, use of special equipment, a small amount of labor and duration of the production process, high automation, and mechanization. The cost price of the mass production in comparison with the production of single-piece and batch production is minimal. This type of production is economically feasible with a sufficiently large volume of output. The necessary condition for mass production is the existence of a stable and significant demand for products. Under the conditions of the economic crisis, the mass production becomes the most vulnerable.
The organization of the production process consists in creating a rational combination in space and in time of the basic, secondary, and servicing processes that ensures the shortest possible time for its implementation. The main goal of the organization of the production process is to save time, ensure high quality products and efficient use of production resources.
The principles of rational organization of the production process.
The following basic principles of rational organization of the production process are distinguised:
1. Specialization is the form of the division of labor (in the industry, in the shop of the plant) and consists in decomposing the production process into its component parts and fixing the strictly limited nomenclature of work for each division of the enterprise (workshop, site, and workplace).
2. Proportionality is a relatively equal capacity of all production units performing basic, secondary and server processes. Violation of this principle leads to the emergence of "bottlenecks" in production, or, conversely, to incomplete loading of workplaces, plots, workshops, and to decrease in the efficiency of the entire enterprise.
3. Parallelism - the simultaneous execution of certain parts of the production process allows significantly reducing the period of production time.
4. Direct flow is the requirement for rectilinear movement of the objects of labor in the course of the technological process. Workshops, services, and sites should be located in the space so that the shortest way of the product's passage through all the phases of the production process is provided and the returns in the route of its movement are eliminated.
5. Continuity - minimizing all the interruptions in the process of manufacturing the product.
6. Rhythmicity - releasing the equal or evenly increasing product volumes in compliance with the plan by the enterprise or a separate workplace, site,and shop. Rhythmicity allows the fullest use of the production capacity of the enterprise and each of its units.
7. Automaticity - the maximum possible performance of operations of the production process automatically, i.e., without the direct participation of the worker in it or under his supervision and control. Automation of processes results in increasing the output of parts and products, improving the quality of work, reducing the cost of living labor, replacing unattractive manual labor with more intellectual work of highly skilled workers - adjusters, operators, excluding the manual labor in the jobs with harmful conditions, and replacing workers with robots.
8. Prevention - the organization of equipment maintenance aimed at preventing deviations from the normal course of the production process (timely preventive maintenance, supply of tools and stock materials, and preventive control of product quality).
9. Flexibility – it provides reduction in the time and costs for the adjustment of equipment with the expansion of the list of product names and a rapid change in the requirements for each. This principle is most developed under the conditions of highly organized production using CNC machines, processing centers, re-adjustable automatic controls, warehousing, and displacement of production facilities.
When designing a production process or production system, one should proceed from the rational use of the principles stated. Decisions should be justified by calculating the comparative effectiveness of possible options.
1.2 The production structure of the enterprise and its main elements
The production structure of an enterprise is understood as the composition of its sections, workshops, and services, the forms of their interconnection in the production process. The main elements of the industrial structure of the enterprise are jobs, plots, and shops.
Unlike the production structure, the general structure of the enterprise includes various services and facilities including those related to the cultural and personal services of the enterprise employees (housing and communal services, canteens, hospitals, polyclinics, and kindergartens, etc.). The production structure characterizes the division of labor between business units and their cooperation. It has a significant impact on the technical and economic indicators of production, the structure of enterprise management, and the organization of operative accounting and bookkeeping. The production structure of the enterprise is dynamic. As the manufacturing technology, management, and production and labor organization are improving, the production structure is also improving. The improvement of the production structure creates the conditions for production intensification, efficient use of labor, material and financial resources, and improvement of product quality.
The main elements of the industrial structure of the enterprise are workplaces, sections, and shops. The primary link in spatial organization of the production is the workplace. The workplace is an organizational unit (in the given specific conditions) that is an integrated part of the production process serviced by one or more workers and designed to perform the specific production or service operation (or their groups) equipped with the appropriate equipment and organizational & technical means. The workplace can be simple and complex. The simple workplace is used for a discrete type of production where one employee is occupied in using the specific equipment. The simple workplace can be single- and -multi-staged. In case of using the complex equipment and in industries that use hardware processes, the workplace becomes complex as it is serviced by a group of people (team) with a certain separation of the functions during the process. The importance of the integrated workplaces increases with the increase in the level of mechanization and automation of production. The workplace can be stationary and mobile. The stationary workplace is located on a fixed production area equipped with appropriate equipment and the objects of labor are delivered to the workplace. The movable workplace moves with the appropriate equipment to the place where the labor objects are processed. Depending on the features of the work performed, the wokplaces are divided into specialized and universal.
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