A highly efficient and convergent optimization method for multipoint tool orientation in five-axis machining

In five-axis machining, multipoint tool orientation has the merit of getting a wider strip width. However, large computing time restricts its application. In this paper, for machining free-form surfaces by toroidal tools, a highly efficient and convergent multipoint tool orientation optimization method is proposed. The method is improved from Middle Point Error Control Method (MPECM), by changing the objective from the maximum strip width to multipoint tool orientation. H-function is defined, and the consistency between multipoint tool orientation and H-function's zero is demonstrated. Based on that, the seeking for optimal tool orientation is equivalent to the computation of H-function's zero. Under the same conditions, compared with MPECM and mechanical equilibrium method (MEM), the computing time of the proposed method decreases to 5% at least. Convergence is ensured by the analysis of the existence of multipoint tool orientation. In the end, the proposed method is validated in machining a mold surface and an aero-engine blade.