Research On Feature Identification And Process Decision-making Of 3D-CAPP

Process planning is the bridge to link product design and manufacture, Computer Aided Process Planning (CAPP) takes advantage of computer to prepare the processing of parts and to turn roughcast into parts according to the requirements of drawings. By inputting to geometrical parameters (including shape, sizes and etc.) and technical parameters (including material, heat treatment, batch and etc.) of parts to be processed into computer, the computer will automatically output the processing procedure and technical methods of the parts.In the past of few years, the research on CAPP starts to focus on the basic data structure of processes and the fundamental design functions. The development interest of CAPP has changed from the automatic generating of process procedure into providing and auxiliary tool for process designers from the aspect of overall product process design and to serve the information construction of enterprise also. It directly stimulates the rapid development of CAPP applications, which generates a new generation of CAPP tool system based on human-machine interface. Certain successes have been achieved in the practical application of enterprise.As the application of 3D-CAD is getting more and more widely used in the domestic manufacturing industry, the application of 3D CAD to enterprise reaches a high level today, it will become one of the most popular design tools for domestic product design in the near future, but the study of CAPP system based on 3D CAD just starts. The CAPP system is 3D environment (3D-CAPP) is an important means to realize the quantitative and intelligent process planning. It has significant meaning to improve product research and development. It is urgently required by many enterprises to integrate process with 3D-CAD, to design processes based on 3D-CAD and etc.In this thesis, during 3D-CAPP system development process 3D parts feature extraction, process sequencing based on genetic algorithm and key techniques of 3D-CAPP system framework were studied and explored. The process describing method is given based on researches of the STEP standard, STEP files structure, through reading and analyzing the information in STEP files, and realized the part feature identification and extraction by using object-oriented programming method. Then a process scheduling question using genetic algorithm (GA) is described, mathematical description of process scheduling was set up, and the working process scheduling based on GA was founded. Studied the 3D-CAPP system framework and development realization approach, and based on UGNX5.0 the 3D-CAPP system was developed and some functions were realized.