Interference-free tool-path planning for flank milling of twisted ruled surfaces

Flank milling is the key feature that the five-axis NC machine offers. Compared with bottom-edge based machining (e.g. flat/fillet endmilling), the machinability can be greatly enhanced by flank milling where the side cutting edge is mainly used. As far as tool-path planning is concerned, the conventional method of the cutter-axis parallel to the ruling lines of the generator curves imposes interference problems including overcut/undercut. In this paper, a new interference-free tool-path planning method fortwisted ruled surfaces is presented. Our strategy is to change the tool orientation and offset distance such that the undercut volume is minimised without global tool interference. The validity and effectiveness of the algorithm is demonstrated via several illustrative examples.