Real-time measurement of temperature field in heavy-duty machine tools using fiber Bragg grating sensors and analysis of thermal shift errors

Temperature is one of the most significant parameters influencing heavy-duty machine tool accuracy. In order to model the correlation between temperature field distribution and thermally induced deformation, and compensate thermal errors, it is critical to obtain the temperature field variations of a precision machine tool in real-time. In this paper, based on fiber Bragg grating (FBG) sensing technology, a novel method for measuring real-time temperature field of a heavy-duty machine tool is presented and the spindle thermal shift error is analyzed. Measurement experiments of real-time temperature field and thermal shift error were carried out on a CNC turn-milling machine tool in shop floor. The variations of ambient and surface temperatures were obtained by the proposed system and the spindle thermal shift errors were monitored by laser displacement sensors at the same time. Experimental results indicate that the surface temperature variations distributed over the machine structure are non-uniform, and the surface temperature field and spindle thermal error have a similar change trend following the ambient temperature. The proposed real-time measurement system could be utilized to analyze the thermal behavior and improve the accuracy of heavy-duty machine tools.