Positioning accuracy improvement of machine tools by embedded cooling channels

Abstract

Thermal error is the most important source of error in the machine tool, and the thermal deformation caused by the temperature rise during the cutting process often leads to lower machining accuracy and poor quality. About 40%–70% machining error of machine tool is caused by thermal deformation. Considering that it is difficult to avoid the generation of heat during the operation or the cutting process of the machine tool, how to predict the temperature change of the machine tool and then design effective thermal management measures becomes an important task in the development of ultra-high precision machine tools. In this study, the thermal deformation of the machine tool structure due to the heat generated during operation is analyzed, and the embedded cooling channels is applied to exchange the heat generated during the operation to achieve the purpose of thermal error suppression. Then, the finite volume method is used to simulate the effect of cooling oil temperature on the thermal deformation and the thermal suppression is conducted on the feed system in combination of the cooler in order to improve the positioning accuracy of the machine tool. From the simulation results, it is observed that when the temperature of cooling oil is lower in the embedded cooling channels, more heat generated is taken away by the hydrostatic guideway and the average temperature of the hydrostatic guideway is reduced, thus decreasing the thermal deformation. Through the thermal suppression experiment of the embedded cooling channels, the positioning accuracy of the feed system can be improved by about 39.1% during the dynamic feeding process.