Trajectory Calculator for Finite-Radius Cutter on a Lathe

A computer program calculates the two- dimensional trajectory (radial vs. axial position) of a finite-radius-of- curvature cutting tool on a lathe so as to cut a workpiece to a piecewise-continuous, analytically defined surface of revolution. (In the original intended application, the tool is a diamond cutter, and the workpiece is made of a crystalline material and is to be formed into an optical resonator disk.) The program also calculates an optimum cutting speed as F/L, where F is a material-dependent empirical factor and L is the effective instantaneous length of the cutting edge.

The input to the program includes the analytical specification of each desired continuous piece of the surface. The output of the program corresponds to an approximate tool trajectory in the form of (1) a set of short straight-line segments connecting the precise trajectory points at user-defined axial steps and (2) the optimum cutting speed for each segment. The program includes algorithms for rounding corners, limiting the depth of cut, and making extra cutouts to prevent excessive stresses. The output of this program is read by a different program that controls stepping motors that move the cutting tool.

This program was written by Dmitry Strekalov, Anatoliy Savchenkov, and Nan Yu of Caltech for NASA’s Jet Propulsion Laboratory.

This software is available for commercial licensing. Please contact Karina Edmonds of the California Institute of Technology at (626) 395-2322. Refer to NPO-45086.