Research ＆ Implimentation On Turning NC System Process Planning Based On STEP-NC

STEP-NC is a new data interface standard between CAM and CNC that is established by the International Standards Organization recently, its data model includes geometry information and process information about a machining part and its geometry information is described based on manufacturing features. The data model lays particular emphasis on the part object but not to do with real machine information and the process detail. Therefore, after importing the STEP- NC data model, the numerical control system should have common process planning ability, and develop to the intelligence, integration direction. The data model is always in development, there is a necessity to carry on necessary enlargement and modification to this data model in actual research and application.Three kinds of STEP-NC controller's framework and its function is introduced in this paper, they are interface type, CAM-built-in type, intelligence type. Process planning was grouped according to the basic thought of STEP-NC, into three levels, i.e. off-line planning, on-line planning and real-time planning. The off-line planning is accomplished in the CAM/CAPP out of CNC, the on-line planning and real-time planning is accomplished in the CNC. The on-line process planning issues involved in the NC system was divided the validation and optimization of process planning route, the optimization of workingstep cutting parameters, toolpath planning and simulation.The basic framework of STEP-NC NC prototype system with process planning ability is simply discussed. The architecture of turning NC system process planning platform is designed. The feature base model and manufacture resource base model based on STEP-NC turning data model is put forword. The process rules in process knowledge depository is particular discussed. The design way of process database is researched.The technique route of STEP-NC NC system process planning is put forword. The way of the validation and optimization of process planning route based on process knowledge database is particular discussed, it is divided into the validation and optimization of Feature-process-chain and Part-process-planning-route. As for the Part-process-planning-route, it is carried out by the feature-priority, process-priority, clustering-priority principles.Finally,the realization of STEP-NC turning NC system process planning platform research is lay out, it lay a certain foundation on the research of STEP-NC turning NC system.