Research On5-axis NC High Speed Constant Feed-rate Machining Technology For Shoe Last

On the background of shoe last NC machining in high speed feed, this paper achieves the goal of machining shoe surface last surface in very constant feed. The method of keeping shoe last machining velocity constant is obtained on the base of some key technologies, such as researching the speed of shoe last cutting contact points, fairing the motion curve of the NC machine coordinates, and the post-processing of5-axis NC machine. Then the proposed relevant methods and theories are demonstrated by using CNC machine experiment. Major contents of study are included:1. The feed speed of shoe last surface cutting contact points is calculated. Firstly, based on the cutting contact points, calculate the tangent of each cutting contact point is calculated. Secondly using the first and second fundamental form of the surface to find the curvature of the shoe last surface and the tool contact points is found, and the speed of shoe last cutting contact points based on the above-mentioned calculated tangent and curvatures is calculated. Finally, the method for keeping constant feed of shoe last machining velocity constant is given.2, The motion trail of the CNC machine coordinates is faired. In this paper, the method of fairing is the combination of energy method and revising selected points method. This method ensures the trajectory smoothing and has a high computational efficiency. At last, the algorithm is verified by the concrete example.4, For a given5-axis CNC machine, the motion relationships and directions of the CNC machine are analyzed, and then the NC machine program is obtained by post-processing. Using the experiment in the5-axic CNC machine, the algorithm which is relevant to the thesis is proved available.