The design and development of a real-time compensation controller of thermally-induced errors for CNC machine tools

Thermal deformation of the machine tool structure is one of critical factors affecting the machining accuracy level. These thermally-induced errors can account for as much as 70% of the dimensional errors on a machined work piece. Although thermally-induced errors can be reduced by applying the new materials with low-expansion coefficient to machine tools, designing the well symmetrical structure of machine tools, as well as controlling the temperature of the machining process, the costs will rise greatly. Furthermore, thermally-induced errors cannot be eliminated completely at the design stage. Hence if thermally-induced errors can be predicted, the use of indirect compensation systems will emerge as the most economical and inevitable course of action. In this paper, a real-time compensation controller of thermally-induced errors for CNC machine tools is designed and developed with the embedded technology. Test results demonstrate this compensation controller predict and compensate thermally-induced erro...