3-Axis NC Tool Path Generation and Machining Simulation for Subdivision

In this paper, we propose a new robust method of NC (numerical control) tool- path planning in CAD/CAM environment. This approach is effective to increase the NC machining efficiency on subdivision triangular surfaces (recursively refined polyhedral mesh) for complex models. Suggested path-planning approach includes three stages: rough cut, semi-finish cut, and finish cut. For each stage corresponding mills (cutting tools) are applied. A flat-end mill is utilized in rough-cut and ball-end mill is used in semi-finish and finish-cut stages. Additional semi-finish cut is applied to avoid tool interference which may occur when the ball-end mill with a larger radius than the radius of curvature of the concave surface is used. As a result of this step, under-cut material volume is decreased and removed in finish cut. An offset surface is generated firstly for finish-cut. In order to increase efficiency, finish-cut stage is applied in the areas where precision of work piece does not meet a user-specified tolerance. A simulation method is introduced to detect tool interference and evaluate precision of machined work piece. At last, interference-free machine experiment was done to test our method and experimental results demonstrate the functionality of it.