The Development Study Of CAPP System Based On PDM

The conventional process planning depends on technological engineers' experience of long career. Referring to data, calculating on working process, drafting working drawing, filling procedure card and process card and so on are all by hand. It can't meet the requirement of diversification and increasingly frequent renewal of modern products. CAPP (Computer Aided Process Planning) provides a good method for resolving the above problems. CAPP can not only realize automation of process planning, but also realize integration of CAD and CAM which is the key of constituting CIMS (Computer Integrated Manufacturing System). Early CAPP technology developed independently of CAD and CAM. In order to realize true CIMS, the information integration problem of CAPP, CAD and CAM must be solved first. Integration of CAD/CAPP/CAM based on PDM (Product Data Management) is an advanced resolution.Hitherto, many CAPP systems have been developed in the world and many approaches to integration of CAPP with CAD and CAM have been presented. But process planning is so complicated and much depending on experiences that there is no commercial software of CAPP up to date as CAD or CAM software. Either CAPP itself or CAD/CAM integrated method is being explored and improved. The research of CAPP based on PDM aims at studying how to realize CAPP in the integrating framework of PDM and presenting some resolutions and methods. The paper has finished works as below:Based on related literature, the meaning and principle of CAPP integrated with CAD/CAM based on developing platform of PDM are analyzed.An approach to automatic building of process planning is presented based on combination of deriving and creating methodsA complete flexible coding rule of part to adapt to the description of part model created in CAD system based on features is presented.A method of adding process feature in geometry feature model by using 3D CAD software, Solid Edge is presented. In this way full feature modeling is realized providing condition for integration of CAPP and CAD.Data transfer and information integration between CAPP and CAM are realized by using VB program and building part feature BOM in the database of PDM system.Selection and ordering of working procedure and working step are realized based on GT (Group Team) principle and part feature BOM and deriving method, and automatic selection of process data and equipment are realized by using logic determination method.Creating and output of the working process card and the working procedure card are realized by using VBA technique.CAPP document management and process management through PDM systemis realized.In the paper, a profitable research on CAPP resolution and integration of CAPP with CAXs is introduced and some application examples in crane products are given, which have certain reference value.