The Variable Cross-Section Helix Turning Trajectory Algorithm Used on the Middle-Convex and Varying Ellipse Piston Skirt

Abstract

In order to turning the skirt of middle-convex and varying ellipse piston, this paper proposes a Variable Cross-section Helix Turning Trajectory (VCHTT) algorithm. it divide the turning trajectory of the piston skirt into transversal and helix, then obtain the coordinates of ellipse transversal cutter-contact points on the basis of centric polar radius arc interpolation (CPRAI) algorithm, and uses line surface intersection method to obtain the coordinates of helix cutter-contact points on the middle-convex and varying ellipse piston skirt. At last，merge two coordinates matrices to obtain the final coordinate surface of cutter-contact points of turning tool. With comparison, it finds that the VCHTT algorithm improves the interpolation accuracy by 0.04um than other methods.