FPGA-based tool path computation: An application for shoe last machining on CNC lathes

Tool path generation is one of the most complex problems in Computer Aided Manufacturing. Although some efficient strategies have been developed, most of them are only useful for standard machining. The algorithm called Virtual Digitizing computes the tool path by means of a virtually digitized model of the surface and a geometry specification of the tool and its motion, so it can even be used in non-standard machining. This algorithm is simple and robust and avoids the problem of tool-surface collision by its own definition. A Virtual Digitizing optimisation that makes the most of specific hardware in order to improve the algorithm efficiency is presented in this paper. A comparative study will show the gain achieved in terms of total computing time. We also present a FPGA-based architecture that can be used to produce rotations with more precision and speed than other well-known classic implementations.