Research On Key Technologies Of STEP-NC-Compliant CAD/CAPP/CAM/CNC Integrated System

With the development of computer technology and information technology,CAD,CAPP,CAM,CNC came into being and were widely used,these computer aided systems have become an important part of product digital design and manufacturing,but also the key to realize intelligent design and manufacturing.Due to the lack of a unified data model among CAD,CAPP,CAM and CNC,complete information sharing among the systems cannot be realized,which makes them an "automation island" and an "information island".The integration of CAD/CAPP/CAM/CNC cannot be realized,which seriously hindering the development of intelligent design and manufacturing.STEP-NC is a new international standard for NC programming data interface that describes processing objects based on manufacturing characteristics.It covers all information required for processing,and supports two-way flow of data and networked manufacturing.This provides an effective way for information exchange and sharing among CAD,CAPP,CAM and CNC,which will promote the integration of CAD,CAPP,CAM and CNC,and also bring revolutionary influence to CNC technology,advanced manufacturing technology,networked manufacturing and intelligent manufacturing.This paper takes the STEP-NC-Compliant CAD/CAPP/CAM/CNC Integrated System as the research object,mainly for STEP-NC based feature modeling,STEP-NC based intelligent nonlinear process planning and Voronoi diagram based STEP-NC complex pocket tool path planning was studied.The main research contents are as follows:(1)The research background and significance of the subject are introduced firstly.Then,the research status of STEP-NC based feature modeling and feature recognition,STEP-NC based process planning,and STEP-NC based tool path planning are analyzed,and the shortcomings of the current research are summarized.Finally,the main research content of this thesis is put forward.(2)Aiming at the problems of feature modeling and feature recognition based on STEP-NC,the feature modeling method based on STEP-NC was proposed.In the method,according to the requirement of feature modeling,the manufacturing feature data model of STEP-NC is improved.Then,according to the information of the improved data model,the 3D modeling software UG was redeveloped by using knowledge fusion language(KF),and the feature modeling module based on STEP-NC was established and the feature model based on STEP-NC was created.(3)Aiming at the problems existing in STEP-NC-based process planning,an intelligent nonlinear process planning method based on STEP-NC was proposed.In this method,firstly.the rules,chaotic firefly algorithm and BP neural network are combined to realize the intelligent STEP-NC clamping planning.Then,the chaotic firefly algorithm was used to improve the BP neural network,and the intelligent STEP-NC macro process planning was realized by improving the nested reasoning of the BP neural network.Then,the intelligent operation plan of intelligent STEP-NC was realized by using the search algorithm of processing operation priority map.Finally,based on rules and chaotic firefly algorithms,an intelligent STEP-NC micro-process specification is implemented,which improves the automation,non-linearity,intelligence,and efficiency of process planning.(4)Aiming at the problems existing in STEP-NC-based tool path planning,a method of STEP-NC complex pocket tool path planning based on Voronoi diagram was proposed.In this method,a Voronoi diagram of the internal and external contours of the STEP-NC complex pocketis generated,firstly.Then,the Voronoi diagrams of the inner and outer contours are combined to obtain a Voronoi diagram for tool path planning.Finally,the minimum travel height method is used to calculate the tool travel distance,and the inner and outer boundaries of the pocketcontour are sequentially shifted inward or outward in their respective voronoi areas,and the STEP-NC complex pocket tool path is obtained.(5)With Visual C++6.0 as the development environment,the MFC application development framework was used to develop the prototype system of CAD/CAPP/CAM/CNC integrated system based on STEP-NC under Win7 system platform.