Abstract
Five-axis CNC flank machining has been commonly used in various industries for shaping complex geometries. This advanced machining operation offers highly flexible tool motion with two rotational degrees of freedom. It produces a greater material removal rate than 5-axis point machining because of a larger contact area of the cutter. Previous studies have developed tool path planning methods for reducing machining errors in 5-axis flank finishing cut of ruled surface. Most methods independently adjust individual cutter locations of a tool path by an optimization process. This usually results in a high-dimensional solution space difficult to search for optimal solutions. In addition, the continuity of the resultant tool path is not guaranteed in those methods. An excessive change between consecutive cutter locations may deteriorate the machined surface quality. To overcome these problems, we propose a novel optimization scheme that optimally adjusts a tool path subject to higher-order continuity constraints. The scheme encodes both the translational and rotational tool motions in compact curve representations. As a result, the number of optimization variables, determined by the curve control points, is largely reduced. A curve subdivision mechanism is applied to adaptively increase the control points until the machining accuracy satisfies a given tolerance. Simulation results have validated the effectiveness of the proposed scheme on reducing geometrical errors on the machined surface. Not only is the efficiency in optimization enhanced, but preserving the tool path continuity also improves the finished surface quality. This work provides a computational approach to increasing the practical value of 5-axis CNC flank machining by tool path optimization.