Research And Development Of CAPP System For Pressing Die Based On XML

Extensible Markup Language(XML), the transmission format for next-generation Internet, is a buzzword in information technology. In cooperative work of many large-scale systems, XML has acted as the only format for data exchange. The application of XML in mechanical engineering industry has become one of the development trends in recent years.Pressing die is the most widely used mold kind, whose total output value accounts for 50 % of the total. Since its products are of a great variety, its structures too complex, its process design takes a long time and it is difficult to cooperate with other systems, it is urgent to solve the process design problems.Based on the actual demands of Pressing Die CAPP(hereinafter referred to as "PDCAPP") system, references to a great deal of information and literature home and abroad and the author's experiences in the development of CAPP system, the thesis analyzes the work flow for designing pressing die process in detail. In order to fulfill the exchange and sharing of process data, the author uses XML to construct the prototype for PDCAPP system that primarily ensures the integrity and consistency of process data of products. According to the characteristics of pressing die process design, the author establishes corresponding models for Use Case of system and Process Quota calculation; meanwhile tests and verifies the feasibility of the adopted techniques and methods.The thesis makes deep researches on the design and development methods of XML-based PDCAPP system elaborating on important technologies for exchanging and sharing data, including mapping principles and realization modes between XML and database, between XML and establishment of BOM forms. Further, tree model of XML documents are used to describe information resources for product manufacturing.The software model is devised with the mode of MVC, and detailed designs of client end and database are offered. With the combination of the object-oriented technique and UML, a Use Case diagram for the system is constructed, which demonstrates the functions and characteristics of the CAPP system from different aspects. Organizing Process Quota system based on the modular idea is convenient for expansion and maintainment of the system.Analysis on the operation of the established PDCAPP system proves the system to be a comparatively self-contained process planning system with good expandability and friendly interface, which can improve the efficiency of process planning and enhance the process design level.