A METHODOLOGY FOR MACHINE-TOOLS ERROR-CORRECTION USING REFERENCE PARTS

In this paper, a methodology is presented for machine tool error correction which uses reference parts as metrological standards. These reference parts have the same geometric shape and weight as real workpieces. Consequently, the proposed methodology minimizes the uncertainty which arises from geometric interpolation, but still yields satisfactory results for multi-axis machine error characterization. A generalized error model is derived to describe the relative error motion between the tool and the workpiece. Iterative search algorithms are presented which increase the effectiveness of the error characterization process. Three case studies are described which demonstrate the application of the methodology for four sample reference parts on three different machines. The results from these studies show that the error correction method can be used to characterize the positioning errors with estimation accuracy approaching the resolution of the machines.