Research On The CAPP Technology For Plastic Profile Extrusion Die

Plastic profile is a plastic product with non-formula section by extrusion. It is applied in many fields, especially plastic window and door. Extrusion die has an important effect on product quality and production efficiency, so it is very significant to research on the CAPP technology for plastic profile extrusion die, so as to assign the process plan of extrusion die accurately and to improve the efficiency of manufacture.In the paper, the demand and the development mode of CAPP system for plastic profile extrusion die (PEDCAPP) are analysed and confirmed, combining with the characteristics of the process planning for plastic profile extrusion die. The architecture of the system and the work flow are designed. With the idea of modularization design, the functional modules are compartmentalized to maintain and extend the system easily.Aiming at the problem that how the part information are described and imported into the CAPP system for plastic profile extrusion die, the method of description and the definition and types of feature are studied. Then with the theory of matter-element and affair-element, the definition about feature matter-affair-element, and the information model of part based on the definition are given. According to the structure characteristic of parts in plastic profile extrusion die, the function that feature information in the Pro/ENGINEER are identified to establish the information model of part for the system is achieved with the method of feature recognition and extraction.The variety and characteristic of process data and knowledge are analysed. The structure models and construction methods of process database are researched to design and establish kinds of necessary database and repository about manufacture. The plan of management and the organization of data in the database are discussed and designed. The application programming interface and the mode of accessing between the database and the main system are studied.Based on the study of manufacture and process of parts in plastic profile extrusion die, the main flow of reasoning in the system is designed to solve the problem of creating process routing, and the hybird process planning of intelligence-based is presented. Using the way of rule-based and knowledge-based, the reasoning method of generative process planning is given. The correctness and validity of the way are illustrated through an example. The rationale and order about the variant process planning of case-based reasoning are introduced in detail Finally, PEDCAPP system which applies the above theories and technology has been developed for process planning of parts in plastic profile extrusion die. Through an example, the process of operation and the interfaces are introduced, and the validity and feasibility of system are testified.