Experience-based CAPP Decision Model And System

Since CAPP development started in 1965, various types of system of CAPP has come into being, especially after 1980s. Owing to the important role of CAPP in the advanced manufacturing system such as CIMS and IMS, CAPP has attracted more and more attention. However, compared with other computer aided technology such as CAD and CAM, CAPP is still a weak point.Traditional CAPP mainly focuses on automatic acquirement of parts information, automation and intelligence of process decision. But it is hard to set up a general model for complicate and non-structural process decision, limiting its wide application. Therefore many enterprises take form-filling CAPP systems. These are mostly card-filling systems for process based on general software like Word/Excel/AutoCAD, not showing the features of computer aided design. Designs will change with different people, not good for standardization of process. Therefore the paper raised experience-based computer aided process decision model and system. The focus are from the automation of process courses to provide designer aided tools based on the whole product process planning, also helpful to information integration.There are 3 types of information in CAPP system: information unrelated to situations of enterprises, information of present resources, and information of process planning experiences. The first two kinds of information can be dealt with by general CAPP, The third kind of information is the most important information for enterprises, but present CAPP systems have not taken the full functions forinformation management and usage, affecting the application of CAPP. As to information of enterprise's process planning experience, the paper raises scientific methods for management and usage. Meanwhile based on general CAPP systems, we may develop tool-CAPP system experience-based computer aided process design. Thus the frame of CAPP system may keep unchanged when employed by different enterprises. Correspondingly, CAPP will be taken by different enterprises and adaptive to update changes.Process decision is a typical half structuralized course based on human-computer intercourse. The decision is multiple-targeting, with complicated restriction, demanding experiences and individuality. It is also somehow random. It is relatively difficult to solve the problem. The paper raises solution to process planning decision based on classified planning, dividing the decision into 4 levels and 10 reasoning engines. The 10 reasoning engines are processing method chioce, machine choice, tool choice, and cutting parameters choice modules etc. The 10 modules and general-control level process decision modules are combined to be aided tools for process planning decision, and providing designers with the most direct help.Under the planning, the paper analyzes five modules in details, including process route decision, processing method chioce,machine choice, tools choice and cutting parameters choice. Various factors have the influence on process decision with different extent. Thus the decision-making module and system is set up based on experiences, and the experiences of an enterprise will be of great effect. Besides the applied CAPP system, the paper tries to put general decision strategy in the system, and completes relative calculating methods (such as machine cost inquiry for machine choice module), thus offering designers more help for aided decision.