Evaluation of the types of multiproduct manufacturing of machine components and some aspects of their design

Type of production, evaluated at the initial stage of production design, determines the basic principles of its organization, mode of operation and specialization. It is particularly relevant to determine the type of production adequate to the given production procedure. Modern technical approaches used to determine it poorly reflect multiproduct nature of such production. The suggested method of determining the coefficient of seriation in multiproduct manufacturing allows evaluating its type, but requires information not always available at the initial stage of the project development. Applying the method of the design based on the reduced program facilitates decreasing its tasks dimensions. Choosing a base component on the basis of quantitative evaluations of the resemblance between components allows reasonably decreasing dimensions of task for designing production sites of multiproduct manufacturing. For this purpose formalized device was developed. On the basis of quantitative evaluation of the resemblance, characteristics of the reduced production program, and labour intensity hours in particular, can be determined. Automation is facilitated due to the formalized objective transformation of multiproduct programs of manufacturing for the sites being designed in the program of base components manufacturing, equal to the set programs on labour intensity hours. Thus, the quality of the design increases and the schedule of the project reduces. 1 Conventional description of the type of production The type of production is the classification of the production, distinguished by the assortment width, periodicity, stability and the volume of output. Three types of production are distinguished in machine building industry: mass, batch and job production (all-Union State Standard (GOST) 14.004-83). When designing production systems, the type of production determines the underlying principles of its organization, employed working procedures (continuous flow process, variable continuous flow and batch process) and specialization of the system being designed [1], [2]. In particular, it is recommended [2]: • In mass production – to use subject-specific assembly lines; * Corresponding author: kondakov1950@mail.ru © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/). MATEC Web of Conferences 224, 01121 (2018) https://doi.org/10.1051/matecconf/201822401121 ICMTMTE 2018

• In batch production -to organize workshops, specializing on definite component parts, and production sites, to use multiproduct assembly lines; • In job production -to organize production sites with technological specialization. The above-noted significantly decreases the dimension of the task of production engineering; specifies it, allows transferring from conceptual engineering to technical project development at the least cost of time and resources [3].
It is particularly relevant to determine the type of production adequate to the given production procedure. However, modern technical approaches (for instance, [4]), which are used to determine this procedure, poorly reflect multiproduct nature of such production, thus increasing the probability of getting erroneous estimate.
Coefficient of seriation (Кз.о) is considered to be the main characteristics of the type of production. It is determined in compliance with all-Union State Standard (GOST) 3.1121-84 by the formula: where O -number of different technological functions performed in a production system within a month; P -number of employees within a production system. Depending on the value of Кз.о the following types of production are determined (table  1).  The value of Кз.о in the type of production (1) can be determined only for an existing production system. It is rather difficult to apply this characteristic at the early stage of production systems engineering.
To determine the type of production approximately, the ratio of output of the components with the same name and weight is used (table 2). Table 2. Data for determining the type of production approximately [4] Types of production Output of the components with the same name produced within a year, pieces Weigh of parts, kg More than 100 10…100 Less than 10 Job production >5 <10 <100 Small-batch production 5…100 10…200 100…500 Medium batch production 100…30 200…500 500…5000 Large batch production 30…1000 500…5000 5000…50000 Mass production >1000 >5000 >50000 Modern scale of the types of production is highly differential [5], and range of values of К3.0 according to the types of production, is determined rather conventionally.
Traditionally, when programming multiproduct manufacturing, the type of production is determined separately for each of the items it contains, for components in particular. On the whole, the type of production is not usually determined, as a result, the components of mass and, for example, small batch production are manufactured at one and the same department. The existing definition of Кз.о does not take into account multi-product nature of the modern machine building production. It is hardly possible to use К3.0 as a characteristic useful for solving tasks of designing production systems on the basis of the existing technical approach.

Defining types of multi-product manufacturing
Let the components of name be produced in the production system. Labour intensity hours for the components Tp output is determined by the formula where Ni -annual production volume of the component i; Tp -value of labour intensity hours per single piece of the component production.
where ni -number of technologic operations, connected with changing forms and dimensions of the component billet; ø ò i t -average value of time per piece performance of the stated operations. The stated operations, involved into any of single technological processes, implemented into the production system, are considered differently. This rather strong assumption allows for a certain increase in the expected use of the production resources of the production system being designed; however, it seems reasonable, as the purpose of the initial stages of the design process is to get the project parameters that will eventually facilitate guaranteed performance of the design assignment.
Number of the operations, performed while manufacturing parts in compliance with the preset production program (O): where ni -number of different operations, performed in i single technological process. If the designed production system functions at the preset regime, the number of workplaces in it is ( ): where Ô -factual annual production time of the equipment of the production system being designed [4]. The value of approximately determines the number of critical workers in the system being designed. Taking into account (4), (5) formula (1) is modified into: In contrast to (1), formula (6) allows formally determining the value of Кз.о for the conditions of multi-product manufacturing and evaluating its corresponding type, but it does not simplify calculations necessary for it and requires information not always available at the initial stages of the project development.
The use of the reduced production program [1], [2] is a frequently applied method of decreasing the dimensions of the design tasks, examined later as exemplified by designing a site for manufacturing components.
The method under discussion is used for designing multi-product manufacturing site, often of small batch and middle batch types, and restricted technological information about the product. Formation of the reduced production program is started with selection of the components, which are projected to be manufactured at this designed site. They are base components.
In the existing literature [1]- [3], [6,7] and others, the term «base component» is not defined, and the recommendations on such selection are insufficient. A base component is usually selected just on the basis of visual comparison of constructions and some technological characteristics of the components to be manufactured on the production site.
Base component is one of the components of the prescribed nomenclature for the production site being designed. Construction of the base component and technological process of its manufacture fully reflect both structural and engineering solutions which are characteristic for all the components of the same nomenclature and corresponding process (unit and batch ones). According to the results of the pair-wise comparison of processes of manufacturing the components of the given nomenclature where a,b -number of technological operations in the process of the components manufacturing i D and j D [9]. where p N -initial production volume of the component recognized as base component.
The number of workplaces in the designed production system can be determined similarly (5): Value P is the most important parameter of the designed production site. The described technical approach for evaluating the type of multiproduct production, determining the reduced manufacturing programs and the number of workplaces at the designed production site was tested on the results of designing object-closed sites of small batch production of step-shaped shaft, disks, gear wheels and in using technologically similar processes. The results prove sustainability of implementing this approach when factually designing production sites.
The advantage of this approach is its standardized nature, allowing for automation in perspective, thus turning it into powerful tool of increasing the effectiveness of designing a production.

Conclusions
• Conventional technical approaches, used to determine the type of the designed production, poorly reflect multiproduct nature of such production, thus increasing the probability of getting erroneous estimate.
• Selection of base components on the basis of quantitative evaluation of technological resemblance allows for a decrease in the dimension of the tasks of designing production sites of multi-product manufacturing of machine components.
• The developed formalized approach allows objectively determining the number of workplaces, which is the most important quantitative parameter of the project, at the initial stage of designing a multi-product production site.