Protocol for machine tool volumetric verification using commercial laser tracker

Abstract

This paper presents a protocol as the preliminary phase of the volumetric verification of geometric errors in a real machine tool using a commercial laser tracker as the measurement system. The final error admissible in machine tool verification is defined as a range by the verification protocol presented in this paper. To obtain it, an independent study of the various sources of error that affect the machine tool’s accuracy was conducted. These errors are the tracking error, the repeatability error, the backlash of each axe, the heating time and the non-geometric errors of the machine. Furthermore, the thermal influence and errors from the measuring system are studied. For all of these errors, different calculation and measurement methods are used by performing a series of real tests on a three lineal-axis milling machine. In this paper, the different techniques that determine the errors of any machine tool are presented in a verification protocol. Depending on the influence of these sources of error obtained by applying the verification protocol to the volumetric error, the protocol determines the adequacy and scope of the volumetric verification process performed.