Research On Algorithm Of Automatic Generation Of Tool Path In Multi-Axis Nc Machining

The NC machining technology is more and more widespread applied in profession of astronautics,aviation,automobile and so on. The surface processing should enable the geometric accuracy, dimensional accuracy and surface roughness of surface parts to achieve the design request completely. Highly effective, precise generation of surface NC machining tool path is key link in research of the NC machining programming algorithm. This article mainly research method of air-foil NC machining, the generation and computation of tool path in machining process was solved. Using the cubic B spline curves to fit the air-foil line, generate airfoil surface, obtain the machining tool path and solve questions of feeding spacing, row spacing, interference inspection, revision etc.The main conclusions of the paper are as follows:1. The air-foil line equation was fit through the cubic B spline curves based on the feature points coordinates. This method greatly reduces computation, ensure the smooth surface, and reduce the inconvenience of the surface intersection between computing and programming.2. Generating CL tool path by using the method of curves of cross sections. Original surface was discrete using the method of discrete on the basic of the direction of cutting plane. According to the tool radius, the offset surface was generated. The cross-sectional plane and the offset surface of the intersection point is the tool path. The error of the tool path processing generated by this method is small and uniform, the distribution of tool path step is reasonable, processing efficiency, programming easy and convenient, easy to modify and check.3. According to changes in the curvature on the surface generation step, Arc approximation method was used to determine a tool path line spacing. It can not only ensure processing efficiency, but also to ensure processing quality.4. Detecting interference of cutter location by polyhedron method. According to the tool surface and the directional distance symbols surface, the direction of the tool along the tool axis and the maximum height of lift interference correction were determined. The efficiency of tool path generation and surface quality was improved, and interference-free tool path generation was achieved.5. To achieve the airfoil structure and airfoil tool path generation by VC++ programming, a prototype system was designed.