Thermal error modeling method for ball screw feed system of CNC machine tools in x-axis

The feed system of CNC machine tool has the characteristics of multiple heat sources and strong time-varying heat generation rate of each heat source. However, previous studies have paid little attention to the time-varying heat generation rate of each heat source, so it is difficult to accurately predict the temperature rise and thermal error of the lead screw. In this paper, Monte Carlo (MC) simulation-integrated FEM method was used to capture the heat generation rate of each heat source in the feed system. Consequently, relationship of the ratio of each heat source to the total heat generation rate of the system with the running time was obtained. Then, based on heat ratios of the heat sources, the torque current of the servo motor in the feed system was proposed to calculate the heat generation rate of each heat source. Finally, based on the finite difference method of one-dimensional heat conduction equation, numerical prediction model for thermal error of the lead screw was put forward. Finally, the accuracy and validity of the calculation model were verified by comparing with the experimental results.