Measurement of Volumetric Positioning Accuracy of a 5-axis Machine By Laser Vector Technique

For a 5-axis machine tool, the 3D volumetric tool-tip positioning accuracy is very important for parts accuracy and quality assurance. Just calibrate the 3 linear axes and the 2 rotational axes is not enough. There are straightness errors for each of the 3 linear axes, and squareness errors between the 3 linear axes, misalignment errors between the linear axes and the rotary axes. Hence, it is very important to measure the over all positioning accuracy by measuring the tool-tip positioning errors. Reported here are the measurement of 3D volumetric positioning accuracy by the laser vector method; the measurement of the rotary axes angular accuracy by a dual-beam laser system; and a theoretical analysis on the tool tip positioning accuracy measurement by a single aperture laser system. The performance of these measurements is relatively simple, fast and straight forward. Its applications in the calibration and compensation of 5-axis machines will improve the parts accuracy and quality without incurring high costs and long machine down time. *Currently with Ford Motor Company in Taiwan.