COMPENSATORY CONTROL OF THERMAL ERRORS FOR HIGH-SPEED MACHINE TOOLS

摘要

Objective of this paper is the development of a real-time thermal error compensator for high-speed machine tools. A vertical type high-speed machine tool having a slant column with lightweight moving slides is used to investigate thermal characteristics. The high-speed machine tool has a large thermal drift error within a few minutes. The thermal time constant is only 3～4 minutes at the spindle speed of 25000rpm. Due to tooling problems of the high-speed spindle, the axial offset errors are also appeared in machined specimens. If-Then rules and thermal mode approaches are applied to remove defects of test specimens. The developed real-time thermal error compensator has the compensation period that is adequate for thermal characteristics of high-speed machine tools. The accuracy of machined surface is improved from 70μm to less than 10μm.