A Hardware/Software Architecture for Tool Path Computation. An Application to Turning Lathe Machining

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 avoids this problem by its own definition but its computing cost is high and makes it difficult for being integrated in standard machining in order to adopt the new ISO standard 14649. Presented in the paper there is a virtual digitizing hardware/software architecture that takes advantage of field programmable gate arrays (FPGAs) to improve the algorithm efficiency and to meet the actual restrictions of the traditional computer numeric control systems at the same time. In order to evaluate the architecture, a prototype was implemented using a commercial reconfigurable platform integrated within a CNC lathe for shoe last machining. The performance of the system for tool path generation was measured for different trajectory and surface precisions using a database of real shoe models. The experiments show a significant speedup for all the cases and maintaining the error of the results below the maximum allowed.