Research On Key Technology Of 3d Machining Planning System

At present,although 3D design software has been widely used in the field of mechanical processing,but enterprises in the process design is still based on two-dimensional drawings,three-dimensional model as a supplement,the three-dimensional model of parts has not been fully applied.With the development of manufacturing informatization,the research of computer aided process System(CAPP)has been paid more and more attention.CAPP system assists users to complete process design and realize data integration through direct operation of 3D model.In this paper,several key technologies in 3d machining planning system,such as process knowledge base,feature recognition and processing method decision,are studied,and applied to process design to solve practical process problems.The main work of the paper is as follows.On the basis of analyzing the source of process knowledge and the structure of process knowledge base,knowledge acquisition is accomplished by data sorting and field investigation,and text or electronic data are summarized and sorted into process knowledge base.The process knowledge is structured by object-oriented knowledge representation,which is convenient for the application of knowledge.The process knowledge base is run by XML technology and database management system.The processing information contained in the part model is reprogrammed by the feature as the basic unit of the part.This paper analyzes several common feature recognition methods,and explains their basic principles and expression methods.In this paper,the feature recognition method based on attribute adjacent-graph is adopted,and the MBD 3D model constructed by 3D design software is taken as the data source to complete the interactive recognition of part features and the extraction of part model manufacturing information.The object of feature recognition is the plate part.This paper discusses several factors that influence the machining method in the process of parts processing,and adopts the method of fuzzy reasoning to make the process decision.The basic concepts and mathematical principles of fuzzy reasoning are briefly introduced.The membership functions of influencing factors are constructed by means of comparative average method and expert experience method.Through the comparison of fuzzy comprehensive evaluation method,the decision of feature processing method is realized.The configuration requirements of system development environment and system operation are introduced.This system is a secondary development based on UG software platform.The system mainly has the functions of knowledge base,MBD model based feature recognition and processing method decision,etc.At last,this paper validates the system function through the enterprise machining parts,and proves the effectiveness of the system.