NC machining is a new technology inmachining. Because of its great technical difficulty, at present, only three foreign companies have this technology, and each has its own system and is not open to each other. Although the technical principle is basically understood in China, there is still a big gap in NC application. The NC system is still mainly introduced from FANUC and Siemens. These general NC systems can not give full play to their performance, CAD and cam can not be integrated, and the price is expensive, which is extremely unfavorable to the application of machine tools in China. Therefore, bevel gear machining urgently needs its own set of CNC system. According to the successful development experience of our institute in NC for many years, we put forward the idea of developing spiral bevel gear NC system. Around this subject, this paper mainly studies and discusses the NC machining theory of spiral bevel gear, and carries out the following research work:
- The meshing principle of spiral bevel gear is introduced, including the tangent plane of spatial surface, normal vector, surface curvature and induced curvature of common roller surface. The relative differential is the tool, and the induced normal curvature is the focus. The blank design and gear cutting calculation are reduced to the pitch parameters and node curvature of a pair of spiral bevel gears.
- According to Gleason CNC machine tool, analyze the machine tool structure, establish the machine tool mathematical model and tooth surface mathematical model in rectangular coordinate system, discretize the tooth surface of spiral bevel gear, and solve the tooth surface coordinates through the input of basic parameters. The tooth surface is simulated.
- Starting from the forming method of bevel gear, determine the pitch parameters of the production wheel and the relative position relationship between the production wheel and the workpiece to adjust the machine tool parameters so that the processed large and small wheels can mesh correctly. The corresponding program is compiled.
- Through the analysis of the tooth surface model and according to the position relationship between the cutter head and the machined gear, the information of the cutter location in the NC machining of spiral bevel gear – cutter center coordinate and cutter axis vector are deduced, which provides a calculation basis for post-processing.
- Based on the principle of five coordinate NC and the established mathematical model, the post-processing formula of spiral bevel gear NC machine tool is deduced, and the angle distribution of machine tool and the position of tool center in machine tool coordinate system are obtained, which provides a method from tool path to NC code generation.
- The tooth surface simulation and the adjustment of machine tool parameters are programmed with VC + + 6.0 and MATLAB, which gives full play to the advantages of MATLAB in numerical operation, such as convenience, rapidity and accuracy, shortens the development time and improves the efficiency.