A new technique for volumetric error assessment of CNC machine tools incorporating ball bar measurement and 3D volumetric error model

This paper presents a useful technique for assessing the volumetric errors in multiaxis machine tools using a kinematic double ball bar. This system has been developed based on a volumetric error model which describes the three-dimensional errors of machine tools. The developed system requires input of the measured radial data performed on the three orthogonal planes, and analyzes parametric errors such as positional, straightness, angular, squareness, and backlash errors. The developed system can also assess the dynamic performance of machine tools such as errors due to the servo gain mismatch. The developed system has been tested using an actual machine tool, showing high potential for error assessment of multiaxis machine tools.