Research On Key Technology In CACD And NC Programming And Web-based Implementation

The author has taken part in three research tasks during his reading for doctor's degree in the CAD/CAM Research Center of Nanjing University of Aeronautics and Astronautics. These tasks are as following: research on the computer aided conceptual design system which is an international research project with UTC, development of a NC programming and milling simulation system which is one of the Key Technologies R&D Program in the 9th five-year plan of Jiangsu Province and the key technology research of Web-based CAD/CAM system which is supported by the Provincial Science Fund for Distinguished Young Scholars.In the international cooperative task with UTC, the author has studied the key technology of computer aided conceptual design including the system framework and the detail development methods. Based on the modern product design methodology and artificial intelligence, a CBR-based system framework is built up. The case description of product conceptual design and the case reasoning process are studied amply. In this dissertation a new model of conceptual design case is put forward. And the model is divided into two forms: the case model in the view of users and the case model in the view of the database. By doing so, the CACD system can enhance the ability of making conceptual designs and increase the data store efficiency. For the first time, the author puts forward the CBR-based conceptual design evaluation system which can make the evaluation of conceptual design more exactly and reasonably.In the research task supported by the Key Technologies R&D Program in the 9th five-year plan of Jiangsu Province, the study focuses on the NC milling programming software development method and the corresponding algorithms on the basis of ACIS. By using the development interfaces provided by ACIS, the author has made some innovation to tool path generation algorithms. Based on ACIS, a new set operation method of loops is presented in this paper. This algorithm, compared with the traditional ones, can simplify the implementation and improve the efficiency. Another new algorithm is studied by the author. By establishing loops' geometrical relationship, this algorithm can automatically get the machining areas among contour loops and island loops. Finally, an algorithm for generating the tool path of NC finish machining based on solid models is put forward. This algorithm can generate the overall tool path of the workpiece in one direction. In some circumstances, it can help the NC programmer finish his work easily.In the research task supported by the Provincial Science Fund for Distinguished Young Scholars, a Web-based CACD and NC programming prototype system is established preliminarily based on the above-mentioned research achievements. By the Internet/Intranet the functions of CACD and NC programming are converted into net services, which will contribute to further development of CAD/CAM.