Research On Toolpath Planning Method Of NC Milling Based On T-spline Surface

With the rapid development of advanced manufacturing industry,modern NC milling technology has become one of the important research contents.In the process of NC milling,the machining accuracy and quality requirements of workpiece which is consist of free-form surface are becoming higher and higher.,and the planning of toolpath has an important influence on improving the machining quality and processing efficiency.Therefore,the design of toolpath planning is a very important key link,and it has great significance to research the toolpath planning method of NC milling.In this paper,a toolpath planning method of NC milling based on T-spline surface is proposed,and the toolpath of rough milling and finish milling is planned.In the rough milling process,a progressive layered machining method is proposed.An improved variable distance offset method is regarded as the key link of this algorithm,and then a series of deformation surface sequences that based on the cutting parameter are obtained.With planning the toolpath of each surface,the whole tool path of the rough milling process can be got.This method can solve the problems of the uneven allowance and rough surface of traditional equal height stratification.In the finish milling process,a toolpath planning method based on space-filling curve is proposed.T-spline surface is regarded as the modeling surface,and then T-mesh is rebuilt.The Box is defined and planned,and the cost of production and the cost of bridge are also defined.Based on the improved Hamiltonian algorithm,the toolpath is generated preliminarily.And then the whole toolpath of the finish milling process,which based on optimized corner by using an improve fillet algorithm,can be got.This method can solve the problems of the grid for space-filling curve is regular rectangle,the toolpath constructed on space-filling curve has many corners,and the tool turns frequently.Based on VS2015 and UG,a simulation system developed to verify the toolpath planning method of NC milling based on T-spline surface.According to the research on the toolpath planning method of NC milling,which is based on T-spline surface,and many actual machining tests.The results show that this method can improve the stability of milling process,and reduce the frequency of machine acceleration and deceleration.It also can reduce the frequency of tool turning,and reduce the length of the toolpath and processing time,thereby it improves the overall processing efficiency.At the same time,this method improves the smoothness of the surface and the machining precision of the workpiece,it can improve the quality of processing.