Robust design method for optimizing the static accuracy of a vertical machining center

In this paper, a robust design method for optimizing the static accuracy of a vertical machining center is proposed. First, the accuracy prediction model was established using screw theory to determine the output accuracy of the machine tool, which was verified by using a DBB and laser interferometer. Then, combining the machine tool's output accuracy and accuracy design requirements to identify the performance equation of the machining accuracy, a model to calculate machining accuracy reliability is derived. Because the reliability calculation model is highly nonlinear, this paper uses response surface methodology to obtain a highly approximate solution for reliability, and the worst reliable working position can also be found from this. On this basis, according to the sensitivity analysis of machining accuracy reliability, the key distribution parameters of geometric error elements that have an important impact are identified. According to the principle of accuracy balance, the error distribution parameters are reasonably adjusted to reduce the effect of errors on the reliability to create a robust design for optimizing the machine tool static accuracy. The research results show that the method proposed only needs to optimize the error distribution parameters five times to make the machining accuracy reliability meet design requirements.