DEVELOPMENT OF A 3D LASER BALL BAR FOR THE VOLUMETRIC ERROR MEASUREMENT OF MULTI-AXIS MACHINES

摘要

Conventional techniques for measuring the volumetric errors of Cartesian coordinate machine tools are time-consuming using laser interferometer or step gauges. For multi-axis machines, where the spindle can swing, the volumetric error calibration is more difficult. In this study, a novel 3D laser ball bar (3D-LBB) has been developed for the easy setup and rapid measurement of the tool position relative to the worktable at any working point of multi-axis machines. The instrument makes use of one laser ball bar and two rotary laser encoders to detect the target path in spherical coordination system. The design of the instrument is discussed and the errors attributes are analyzed to enhance its accuracy. Applications to the volumetric error measurement of a robot and a serial-parallel type machine tool have demonstrated the capability of this 3D-LBB with high precision.