Tool path verification and gouge avoidance in five-axis machining

Abstract

In five axis machining of curved surfaces, the cutting surface of the tool, whether it is a sphere or a torus. Lies very close to the design surface. Quite often the cutting surface falls below the design surface resulting in a gouge or overcut. These gouges are unacceptable. Thus, for a tool path to be acceptable it must be tested for gouging and corrected to avoid any gouges. The thesis of this work is to develop a swept volume generation method, which allow fast modeling of machined surface and quick detection of gouging. Subsequently, gouging tool positions can be corrected to generate a gouge free tool path. Rather than using the traditional boolean operations method, a new sweeping technique based on identifying "generating curves" along the tool path is developed. This technique reduces computation time significantly and consequently speeds up the simulation process. The new is augmented with a gouge-detection technique developed based on sectioning the generating curves by parallel planes. This results in planar representations of the moving tool, which enables the gouge detection and elimination to be done in two dimensions, thereby reducing complexity.

A computer program (Swept Volume Simulator SVS) has been implemented for fixe-axis machining based on the new techniques and was verified experimentally for different test pieces. It was also compared with the simulation results from the Z-map technique. The results of the experimental verification show the method to be accurate to within 15 um for the test pieces. Furthermore, the computation time for the new technique is significantly less than the Z-map method. It is concluded that the new method allows fast simulations and accurate verifications of five-axis tool paths.