| This paper makes researches on the methods of CAD/CAM system integration, orienting the background of NC lathe application. There are three main parts in the research work. One is CAD/CAM integrated application system, which provides the platform for information integration and function integration during the process of CAD/CAM. One is machining feature extracting of revolution parts. Machining feature information is the bridge between the design information of parts and manufacturing process. Another is NC lathe process planning based on features. This part, which is the key of CAD/CAM integration, not only includes the research of CAPP but also deals with the integration of CAPP and CAM. Through the corresponding modules, the mapping from features to number-controlled machining is realized. So the unification of part design and manufacturing is achieved. The utility and commercial value of CAD/CAM integrated system depend on good software application framework. So, A "bus-component" type graphics application framework (GAP) is designed and realized in this subject, which is the base of implementing an integrated system. The design of GAP is separated from the specific application of CAD/CAM. And the work on GAP is to provide an extendable application framework, convenient graphics programming interface and some reusable function components.The paper discussed the architecture and implementing methods of CAD/CAM integrated system oriented NC lathe application firstly. The main objects of designing of integrated system are information integration and function integration in CAD/CAM. There are two main types of information need to be managed. One is workpiece information. The other is machining knowledge base. The first mainly includes parts geometrical information, feature information, process information and so on. The second includes tools information base, material information base, material cutting knowledge base and etc. The functions of the system deals with graphics operation, feature extracting, process planning and so on. The system is implemented on the theory of components and hierarchy, which assures the system with good application structure and extensibility.Feature extracting is taken as the key method to solve the integration of CAD and CAPP. Many researches have been done on the aspect of modeling part feature. Feature is a wide concept. This paper defines in formation model of machining features of revolution parts in the system, puts forward a feature extracting algorithm based on contour of revolution parts, which is adapt for outside outlineof resolution parts. Based on the upper researches, a module of feature extracting is realized in the system.NC process planning based on features can be divided into three parts, which are automatic sequential operation planning based on features, machining parameters compilation and NC tool-path planning. Sequence of operation is the "skeleton" of process. This paper puts forward the automatic sequential operation planning method based on the feature extracting information. This method sets the default process of parts automatically. Compilation of machining parameters selects from knowledge base or fills out related parameters directly through interactive manner. The tool-path reflects directly the final NC cutting manners, and both process simulation and NC code translation depend on the information of tool-path. Therefore, the NC machining tool-path based on process information finally realizes the integration of CAPP and CAM.At the tail of this paper, infrastructure, realization methods and running mechanism of the graphics application framework is introduced. |
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