Tool Path Planning for Machining Free-form Surfaces

This paper is about new iso-parametric tool path planning for machining trimmed freeform surfaces. The trimmed surface has been re-parameterized by two different parameterization techniques, namely, the partial differential equation method and the newly developed boundary interpolation method. The efficiency of the scheme has been measured in terms of path length and computational time needed for machining some typical surfaces. Conventionally, the forward-step is calculated by approximating the cutting curve with the osculating circle. The actual tolerance of the forward-step may go beyond the prescribed limit due to the circular arc approximation. In this study, the actual cutting curve has been considered to keep the tolerance in the forward-step below the prescribed value. The new algorithm has been tested on some typical surfaces and the results show a significant improvement in the surface profile in terms of tolerance of the forward-step.