Dynamic calibration of the positioning accuracy of machine tools and coordinate measuring machines using a laser interferometer

This paper describes a method for evaluating the positioning accuracy of machine tools and coordinate measuring machines (CMM) under dynamic conditions. It is based on the Hewlett Packard 5519A laser interferometer which is capable of performing dynamic calibration. Such method uses the A-quad-B pulses from the machine encoder as the position trigger signals, thus enabling to make measurements on-the-fly. A software package has been developed so as to permit the data acquisition and presentation of the positional errors in accordance with ISO 230-2 standard. Thereby, the accuracy and repeatability of positioning of the machine axis on test are assessed considering the ISO parameters. This technique provides a more realistic and detailed picture of the errors of the machine. Such errors are measured in high resolution and dynamically. Application of this positional error calibrator on a moving bridge type CMM is undertaken. The results are presented and discussed. (C) 2003 Elsevier Science Ltd. All rights reserved.