Research On Key Technology In The Development Of The CAD/CAM System Based On ACIS

In this dissertation, the key technologies in the development of the CAD/CAM software based on ACIS geometric engine are studied in depth. And tool path generation methods are researched with emphasis.The requirements of the manufacturing-oriented CAD/CAM systems are analyzed. The general mainframe of the 3D Modeling and NC Milling Programming Software in the Superman2000 CAD/CAM system is established. The system structures and data flows are designed. Furthermore, system function design is carried out.ACIS geometric engine is analyzed in depth, including its systematic structures, data structures of models, and the interfaces between application and ACIS. According to ACIS characteristics, the fundamental algorithms of NC modules are studied. All of that establish stable foundation for the development of CAM system.The NC programming technology of complicated planar pockets is researched. Based on ACIS, algorithms of machining along contours of workpieces, zigzag milling, and contour-parallel milling are designed and implemented. Thereinto, the algorithm of zigzag milling programming is optimized, and a new algorithm of contour-parallel milling is designed. The algorithms of rudimental-area supplement milling and leftover machining are researched.The related algorithms to three-axis rough milling are studied based on solid surfaces. And relevant extension is made to suit three-axis rough milling. The tool path generation methods are studied in depth for the machining of pocket-type, raised-type workpieces, and workpieces with open pockets. With the above- mentioned algorithm, positions of the pre-drilled holes for starting milling can be alternatively determined. At last, tool path generation method for 2.5D models is researched.Tool path generation method of planar-section finish machining to surfaces of solid models is studied. Tool path is generated by the treatment to the intersection curves between the offset of models' surfaces and drive plane. The virtual blending between surfaces is introduced, and offsetting surfaces of the edges and vertices of the machined solid model are generated to make the implementation of the algorithm more easily.The above-mentioned key technologies studied in this dissertation have been successfully applied to Superman2000 CAD/CAM system. It is proved that the results given in this dissertation are effective and feasible.