Interference-free tool orientation determination by a virtual enveloping element for five-axis machining of a freeform surface

In machining freeform surfaces on five-axis machine tools, it is very important to determine the location of the cutting tool. The commercial computer aided design/manufacturing (CAD/CAM) software for five-axis machining often lacks flexibility to specify the appropriate tool orientation and toolpath for surface machining. This paper presents a new methodology for determining feasible tool orientation of a toroidal milling cutter with collision and gouging avoidance in five-axis machining of a freeform surface. To avoid collision and rear gouging, a virtual enveloping element is proposed that is derived from the properties of the local and global surfaces. The set of tool orientations can be found first by confining the cutting tool within the virtual enveloping element. Then, the principal induced normal curvatures between the freeform surface and the cutting tool need to be evaluated to offer the criterion of gouging detection. To achieve the best combination of scallop height and machining efficiency, the contact length is also calculated for various tool orientations. The toolpaths generated by the proposed method are verified through solid cutting simulation and a trial cut on a five-axis machine.