A line measurement method for geometric error measurement of the vertical machining center

This paper presents a new line-measurement method for three-axis CNC (computer numerical control) vertical machining center. The measurement method measures the twenty-one geometric error of the numerical control machining center through using the laser interferometer and ball bar. The objective of this research work was to illustrate the measurement method (a line measurement method for geometric error measurement), measurement system and testing results with specific experimental conditions that may provide an easy way to measure the geometric errors. To estimate the geometric errors of the machining center, both direct and indirect measurement methods are used to predict the errors. The ball bar is used to measure the squareness errors of the machining center. The linear, angular and straightness errors estimated by the laser interferometer provide the particular reference value at the same time on the numerical control machine tool and geometric precision detection. Therefore, the twenty-one geometric errors of the machining system that reflect on machine tool can be predicted by a line measurement method which comes up convenient and time-saving way as compared to others line methods such as 12th line, 13th line and 15th line etc.