Research And Verification Of Direct Generation Of B-Spline Path For Mold Machining

Mold is an indispensable part of the manufacturing industry.CAM(Computer Aided Manufacturing)technology is constantly developing and widely used as a major means of mold processing.Most of the tool path generated from CAM software are small segment paths,which will lead to the discontinuity of speed and acceleration in actual processing,thus the quality of work-piece surface processing is reduced,and because the length of small segment is too short,the NC system can not achieve high-speed machining.Nowadays,the most commonly used solution is to use parametric curve to smooth the tool path of small line segments,but this method lacks geometric information of work-piece in the process of smoothing,so may lead to problems such as reduced accuracy and loss of feature points.In order to solve the problems in current methods,this paper presents an algorithm for directly generating B-spline tool path in CAM software.The geometric information of the model in CAM software can be used to ensure the accuracy of tool path,so that the generated tool path are not only smooth,but also have high accuracy.The main research contents of this paper are as follows:(1)Using the trajectory spacing control algorithm based on iso-planar projection to generate the initial cutter location,the shortcomings of the algorithm are improved;(2)Designing the direct generation of B-spline tool path algorithm,using(1)generating the initial cutter location of a planar,the initial cutter locations are grouped to generate the piecewise tool path based on Bezier curve in this planar.In the process of generating,new cutter locations are added to ensure the accuracy of the curve.Then transforming the cubic Bezier curve of the same planar into a cubic B-spline curve.After the complete B-spline path is generated,the processing procedure of the specified machine tool is generated by post-processing;(3)Developing CAM software for multi-axis machining of high-end mold,the software supports B-spline path output.In this paper,the proposed algorithm is simulated and verified by experiments.Firstly,the B-spline path generated by this algorithm is simulated and analyzed.It can be concluded that the B-spline path generated by this algorithm is not only smooth,but also close to the tool path of the small line segment.The algorithm is applied to actual machining,and compared with the existing smoothing tool path method.It is found that the overall effect of the work-piece processed by this algorithm is the best,not only the surface is smooth,the quality is good,but also the processing efficiency is high.