Chip geometry based tool force variation model for dynamic error correction in diamond turning

An essential ingredient in the fabrication of diamond turned surfaces is the accurate control of the relative position of the tool and the workpiece. One way to realize this is to use the cutting force information in real-time to infer the resulting surface roughness and to ultimately correct any dynamic errors. A crucial factor in the use of force information is modeling of the relationship between the force and surface roughness. In this paper, a chip geometry based force model is obtained. The force variation is expressed as a function of the depth-of-cut variation that results from slide vibration and/or spindle relative motion. This force/position model is then used as an admittance relationship in the overall force-based feedback control that utilizes a PZT based, high bandwidth, servo module to minimize the roughness of diamond turned surfaces.