Study On Key Technologies Of Supporting Complicated Parts Numerical Machining And Its Application

Manufacturing has played an important part in the development of economy. Today, great changes in manufacturing industry accelerated the development of product market from unitary and mass production to plural and individualized production. And complicated parts have become more and more familiar. Since the designing of their fixtures is not easy, it's hard to do process planning.With the aid of IL&SM fixture system put forward by Professor Li Beizhi, variety of complicated parts are able to be located and fixed reliably. The location of the blank is reached by locating components and the initial state is memorized throughout the machining process. The locating box is composed of six knock-down boards, and the six machining direction according to those boards can be accociated with similar process.In this paper, great research has been carried on in the field of NC machining technology of complicated parts based on IL&SM flexible fixture, including the following four aspects:1. Selection of CAD/CAM platform and study on the technology of second-time developmentThe characteristics of some common CAD/CAM softwares are analyzed and UG is selected as CAD/CAM platform. Then the second-time development kits provided by UG are discussed.2. The analysis of the error of fixture and NC machining precisionThe error of fixture is one of the main source of NC machining error. The machining error caused by the error of fixture needs to be analyzed because it should be compensated. A mathematic model is set up to express the process of datum transform based on IL&SM flexible fixturing system. The machining error caused by the error of the fixture is calculated with the aid of this model, and a solution of error compensation is proposed. Then an example is given illustrating the analysis of this error.3. Optimum design of technical parameters based on IL&SM fixturing technology To complicated parts, selection of appropriate machining parameters is fairlyimportant for high machining quality. Some parameters including cutter property, feed-speed, cutting depth/width, engage/retract method, finishing stepover, cut method and operation allowance/tolerance are discussed, and the optimum selection rules is proposed, which give a hand in process planning.4. IL&SM fixturing technology oriented CAPP/NCP integrated systemAn IL&SM fixturing technology oriented CAPP/NCP integrated system is developed using the basic functions and second-time development kit provided in UG, which extends the functions of UG platform. Two method are provided in this system - template part based planning and typical feature based planning. With the aid of this system, people can make full use of those useful machining processes and knowledges, and do NC programming more effectively. At the same time, CAPP and CAM is integrated.Jin Yusong (Mechanical Manufacturing & Automation)Directed by Professor Li Beizhi...