A study on improvement of ball screw system positioning error with liquid-cooling

The demand for higher productivity and tight part tolerances requires machine tools to have faster and more accurate feed drive systems. As tried and tested technology, ball screw drive systems are still used in a majority of machine tools due to their low cost and high degree of stiffness. A high-speed ball screw drive system generates more heat and results in greater positioning error, adversely affecting the accuracy of machined parts. In this paper, we discuss the placement of a liquid-cooling system using water, coolant oil, light oil and cutting oil as coolants in a ball screw shaft to avoid thermal errors and achieve temperature equilibrium faster. In order to estimate the positioning error and thermal distribution of the ball system and effectiveness of the liquid-cooling system, all possible heat gain-loss sources were analyzed and considered calculation factors. The following paper also presents degree of positioning error improvement when a circulation liquid-cooling system and forced liquid-cooling system were employed. When comparing the predictions and the experimental results, we can see very significant cooling performance and a high degree of consistency between prediction and reality.