Standardization in CAPP application

Standardization in CAPP application

1 overview

standardization has developed with the development of modern industry. It is not only the product of industrial development, but also the symbol of social development. At present, science and technology are experiencing a new period of development. Modern standardization principles and methods not only improve production efficiency, but also help to improve product quality and reduce costs; It not only meets the changing needs of society for products, but also meets the requirements of social competition. After China successfully joined the World Trade Organization (WTO), standardization, as a new discipline, has been paid more and more attention by people. Especially in the information age, standardization is an indispensable and important means, as is its application in CAPP. CAPP is the abbreviation of computer aided process planning, which is generally translated as computer-aided process planning. CAPP has two basic working modes: human computer interaction design and computer automatic design. Most of the early developed retrieval CAPP technology systems use human-computer interaction to design the process, while the recently developed CAPP technology systems, whether retrieval, semi creative or expert knowledge, mostly use automatic design. In the working process of CAPP system, it is inseparable from the support of some databases (such as part database and comprehensive database), such as retrieval CAPP system. It uses the principle of group technology, that is, the objectively similar parts are summarized into groups, then subdivided into part families, and the common manufacturing methods of each part family are integrated, so as to design a typical process suitable for the part family, Then various typical processes are stored in the system, and the process is compiled by using the retrieval CAPP system, that is, taking the code of the part family as the key, and retrieving the corresponding typical processes that have been stored in the system by means of data retrieval, so as to complete the process of process design. It can be seen that in the application of CAPP, there are various "repetitive things and concepts" for us to standardize. According to the definition of "standardization" (gb3935.1), standardization refers to the unification of "repetitive things and concepts" (in economic, technological, scientific, management and other social practices) through the formulation, release and implementation of standards, so as to obtain the best order and social benefits

2 the necessity of carrying out the standardization of CAPP application

why should we vigorously carry out the standardization of CAPP application? According to China's national conditions and the actual situation of most enterprises, mainly because the process procedures and process documents are the basis and original data for all production preparations, production planning and scheduling, cost planning and accounting, and are the laws and regulations of production operations. The quality of process preparation directly affects the cost, material consumption, quality, output, etc. of parts. It is a very important work of factory production, It is the basis for the production and business activities of the factory. CAPP system is still a commercial system design software at present. Its service object is not a specific manufacturer, but various types of industries in the whole society. From this point of view, at the beginning of introducing CAPP technology, an enterprise should carry out the secondary development of CAPP application software based on the characteristics of the enterprise after nearly one year of research and development and countless experimental improvements, and this is only the beginning of the standardized means of CAPP application

according to the current situation of the application of CAPP Technology in China, it can be seen that although the application and promotion of computer aided design (CAD) technology is very fast, the designers of many enterprises have already "lost the drawing board" and the technicians have "put down the pen", but the CAPP application of most enterprises can only be regarded as just starting. For some enterprises that have introduced CAPP system, the work quality achieved by using CAPP system may be far from its original intention; Even those enterprises that have applied computer aided design (CAD) and numerical control technology (or machining centers) hope to integrate CAD and cam as soon as possible, which also requires mature and high-level CAPP as a bridge between CAD and cam. In addition, computer integrated manufacturing system (CIMS) is also being developed and introduced in China, and CAPP is also a key link in CIMS. In order to improve the whole process level and develop the use of high technology, we must also accelerate the development of CAPP. After understanding the importance of CAPP, let's understand the position and role of standardization in CAPP development. In the development process of CAPP system, a large number of different types of process data are required, and different disciplines will also be involved: methods, materials, tooling equipment, management methods, etc. through a large number of induction and sorting, one of the supporting documents of cap system - process resource database will finally be formed. One of the secondary development contents of enterprises at the beginning of introducing CAPP system is to choose the contents of these process resource databases as enterprises. During this period, it is impossible to do this work well without the intervention of standardization personnel

3 standardized working methods in CAPP application

standardization is a systematic process that unfolds step by step from theory to practice and from thought to action according to a specific logical order. According to the structural characteristics of the Department of standard chemistry, the standardized means in CAPP application can now be as follows

3.1 system engineering method

the representative model of system engineering method was proposed by American Hall (.A.d Hall) based on three-dimensional spatial morphology. The constructed model is like the space rectangular coordinate system in higher mathematics. Its x-axis, Y-axis and 2-axis respectively represent the three-dimensional time dimension, logic dimension and knowledge dimension in the model. The first two are about problem-solving procedures, The third dimension is about the professional knowledge that must be possessed in order to solve some problems at different stages. The time dimension is divided into seven stages: planning, planning, development, production, distribution, use and elimination (the end of the system life cycle); Knowledge dimension includes engineering technology, management science, law, sociology and so on. Hall model can make people see at a glance the necessary steps to complete a project, and the work to be done and the necessary knowledge at each stage, including the expert team. In the logical dimension of Hall's model, clarifying the problem is put in the first place in order to avoid blind engagement, which is very important

3.2 decomposition and combination methods of the system

according to the basic concept of a system with better PCU performance, the system can be defined as the collection of interacting units. The constituent units in the collection are different from and related to each other, and have certain levels and laws. Through interaction, some unique functions can be realized, and the exchange of material, energy and information with the environment can be carried out. At the same time, the feedback system can be effectively controlled. Standardization itself is such a process. According to the constituent attributes (purposefulness, comprehensiveness, relevance, integrity and adaptability) of the system, we can use the means of decomposition and combination of the system, that is, to analyze and synthesize the objects that need to be standardized (a large number of facts show that the standardized objects are a system or a component of the system), so as to clarify their overall layout, hierarchical relationship and functional matching of each part. For example, using the system decomposition method, complex tasks can be reduced to simple tasks to be solved one by one; However, the combination method of the system can understand the connection mode and mutual relationship of each unit in the system. By understanding the functions and transmission laws of these units, we can better explore the best comprehensive functions of the whole system, so as to achieve the best order within the system

3.3 similarity method

similarity method is widely used in standardization work, and the most important application is similarity analysis. The analysis results of system structure show that different systems often contain the same or similar units, and different units contain the same or similar elements. In this way, standardized functional units with the same elements can be formed through similar merging and optimization simplification, creating conditions for generalization and combination. For example, the use of group technology in CAPP is a typical example

3.4 specific methods of standardization

in the current standardization practice, there are also some specific standardization methods established by Huang Danhua, deputy director of SASAC, in combination with the essential characteristics of standardization, such as simplification, unification, generalization, typification, serialization, combination, programming and comprehensive standardization. Through the above means, the standardization of different things and objects in CAPP application can make the CAPP system more scientific and reasonable, and make it better serve the process design work

4 standardization work content in CAPP application

enterprises will be impacted by information from all aspects all the time, from the secondary development after the introduction of CAPP to the use of CAPP for process design. Driven by the huge productivity of science and technology, this system will become more and more perfect. From a macro perspective, the objects of standardization mainly include the following four aspects:

4.1 promotion of process standardization principles and technologies

with China's accession to the World Trade Organization (WTO) and the acceleration of the pace of reform and opening up, various process standardization principles and cutting-edge technologies in various countries will continue to enter the country. Process standardization managers have the obligation to promote and apply advanced standardization principles and technologies to the process design of enterprises, Make the process design of the enterprise into the process of modernization, gradually cultivate the process designers of the enterprise, so that they have good standardization quality and cultivation, master and apply the principles and scientific methods of standardization, and solve the practical problems in the work

4.2 expansion and management of process resource database

process resource database is an important supporting document of CAPP and a powerful guarantee for the quality of process design. As enterprises constantly adjust products and output in market competition, constantly update production technical conditions, and constantly absorb advanced scientific and technological content, the scientificity and rationality of process resource database become more and more important. For example, the update of equipment will cause the change of corresponding parameters in the database; The utilization of new materials will cause changes in the process quota in the database, and the expansion and improvement at any time will promote the CAPP system to be more advanced and reasonable

4.3 setting and updating of process template

process template is another important part of CAPP. Whether it is secondary development or system operation, the importance of process template cannot be ignored at all. It is an indispensable tool for technologists to carry out process design, and it is the link and bridge between process design and manufacturing. Therefore, the timely setting and updating will make the use of CAPP more handy, and the communication between the content of the process template and the standardized management information is always on, which should attract enough attention

4.4 the role of standardization supervision cannot be ignored

the characteristics of enterprise standardization work are strong policy, strong professionalism and wide coverage; We should also carry out extensive coordination, deal with the relations involving all aspects of enterprise production and operation, mobilize the enthusiasm of all aspects of personnel, and jointly do a good job in standardization. However, in the process of using CAPP system for process design, process designers often rely too much on CAPP and ignore the role of standardization, especially when it comes to implementing the national