Abstract: For open sculptured concave surface machining by the toroidal cutter, a new five-axis rotary contact tool positioning algorithm is proposed based on the reverse thinking of the traditional multi-point machining. The initial tool location in the local coordinate system on the offset surface of the design surface is determined. After the backwards and side tilt angle of the tool are optimized, there are two contact points between the tool surface and the design surface around the minimum direction of curvature without gouging. The traditional multi-point tool positioning algorithms search the optimal tool positions by the two contact points; however, the rotary contact tool positioning algorithm finds the optimal tool positions by the backwards and side tilt angle of the tool and the two contact points do not need to be figured out. Computational example and machining simulation show that the rotary contact tool positioning algorithm can not only generate gouge-free multi-point tool positions to avoid additional local gouge checking and correction process, but also produce about double machined strip width to raise the actual machining efficiency by contrast with UG algorithm.

Key words: Five-axis, Multi-point machining, Sculptured surface, Tool positioning