Comparison of accuracy stability using a thermal compensator and grating ruler

作者：Liu, Kuo^*; Sun, Mingjia; Wu, Yuliang; Zhu, Tiejun

来源：Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2016, 38(8): 2403-2411.

DOI：10.1007/s40430-016-0491-0

• CNC machine tool
• Feed drive system
• Thermal error
• Thermal compensator
• Grating ruler

The disadvantages of the closed-loop control of CNC machine tool feed drive systems using grating rulers were analyzed, including the reason why thermal compensators cannot be widely used on machine tools. A new modeling method based on the heat transfer theory for half-closed-loop feed drive systems is proposed to solve the poor robustness of commonly used thermal models, and the modeling and parameter optimization procedures are presented. In the new modeling method, the thermal errors caused by ambient temperature variation and ball-screw friction were calculated separately. Based on the heat production, heat conduction, and heat convection theory, the ball-screw temperature field at any given time can be obtained to predict the ball-screw thermal errors. Experiments were conducted on a vertical machining center VMC1100p, and the test process, compensation principle, and communication configuration between the compensator and CNC are presented. Finally, the accuracy stability of a half-closed-loop feed drive system after the compensation was found to be far higher than that before the compensation, and also far higher than that obtained under closed-loop control using a grating ruler.

• 出版日期2016-12
• 单位吉林大学