The Research On Some NC Key Technologies Based On The Combined Surface Of Expander Tool

Traditional CNC systems often has only linear and circular interpolation algorithm, which is fully capable to cutting the shape of simple parts. But this can not meet the growing demands of industry and people's living standards with the development of modern science and technology. So, a large amont of procedure will be produced when use linear and circular interpolation algorithm and that will not only increase the time that NC system to calculate it and reduce the efficiency of the system but also difficult to meet the high-precision requirements of modern products.In this paper,the study of direct interpolation with the carrier is combined surface of Expanding Head which used in oil pipeline. Including:1. Analysised the basic principles of interpolation method and NURBS curves and surfaces and proposed a direct interpolation algorithm of NURBS curve.2. Study the NURBS curve real-time interpolation method and the key issues, analysised the relationgship of feed step and chord error and make the Interpolation step to achieve with the chord error of adaptive adjustment come ture.3. Simulate the real-time interpolation by softeware, obtain the simulation curve, feed step curve and chord error curve. Analysis of the results of interpolation and verify the correctness of the algorithm and proved the feasibility and efficiency of real-time NURBS curve interpolation.4. At last, study the key technologies of real-time interpolation of the combined surface including tool path automatic generation and the method of error control. All of this can make a theoretical foundation for the real-time interpolation of complex surface.