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

Flank milling is the crucial 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 the flank milling where the side cutting edge is mainly used. As far as tool path planning is concerned, conventional method taking the cutter-axis parallel to the ruling lines of the generator curves does impose interference including overcut/undercut problem. In this paper, a new interference-free tool path planning method for the twisted ruled surface is presented. Our strategy is to change the tool orientation and offset distance such that the undercut volume is minimized without global tool interference. Compared with previous method relying on the constant tool orientation or offset distance within the ruling vector, the undercut/overcut volume can be minimized without causing global tool interference. The validity and effectiveness of the presented algorithm is demonstrated via several illustrative examples.