The Linear Interpolation Error Analysis For Cylindrical Cutter Of Five-axis CNC System

Non-developable ruled surface widely used in Impeller blade of aero engine, blower and so on. Impeller blade impeller always work work in a harsh environment, and need to run under the environment of high temperature, high pressure usually. So the machining precision of impeller blade will have a great influence on whole machine performance and life. The demand of surface machining accuracy and processing efficiency are more and more high along with the rapid development of science and technology. How to efficiently produce high quality surface has become an important issue in the manufacturing industry. Multi axis machining of impeller parts is the key and difficult point in numerical control technology. With the rapid development of NC technology, five axis CNC and has become an important method to improve the ruled surface parts processing quality and efficiency in recent years. In the five axis NC machining of complex surface, the factors affecting the machining accuracy of the workpiece are numerous, among which the nonlinear error caused by the linear interpolation function of NC system is relatively small. The interpolation function between the adjacent cutter location points is provided by the CNC system in order to solve the problem of complex surface forming in CNC system. The use of linear interpolation, circular interpolation and spline interpolation is most at present, and linear interpolation is the most typical method. Therefore, the paper studies the linear interpolation error for cylindrical cutter frank milling rule surfaces in five-axis CNC system. And have scientific significance and engineering application value. The main work completed is as follows:Firstly, introduces the basic theory of single point offset (SPO), double point offset (DPO), three point offset, least square method and best uniform approximation method and tool-path planning error model of their. Calculation the tool center point position and cutter axis vector by double point offset (DPO) and best uniform approximation method. On this basis, compared with the path planning error caused by them. The results show that the cutter position planning precision of best uniform approximation method is obviously higher than that the double point offset method.Secondly, obtain the cutter center position and cutter axis vector by the two kinds of tool path planning method, calculation interpolation points and cutter interpolation vector direction between adjacent cutter location points using linear interpolation method. And moving path of tool axis. Then simulated actual working surface by tool envelope surface simulation which is obtained by cylindrical cutter linear interpolation motion through the envelope principle.Third, according to machining principle error in flanking milling intractable ruled surface by cylindrical cutter. Making the ideal surface as the reference surface, Using Newton method to calculate the minimize distance between the envelope surface and the design surface and the maximum value is taken as the linear interpolation error at the corresponding position, and the error model of linear interpolation is obtained.Finally, research the law and size of the nonlinear error of numerical examples, and analysis the influence factors of them. It has practical significance and lays the foundation for the control of nonlinear error in the next step.