Dynamic performance analysis and optimization method of the horizontal machining center based on contact theory

Abstract

A dynamic performance analysis and optimization method of the horizontal machining center based on contact theory was presented in this paper. The contact stiffness models of ball screw joints and guide joints were proposed based on contact theory, and the predicted values are in good agreement with the experimental results. In particular, the prediction errors of the ball screw joints are within 2.8% compared with the 13 sets of experimental results of THK Company for 26 types. The analysis principle of dynamic performance was given by modal theory. With the goal of reducing the sum of modal flexibility and strengthening the weak modes, static flexibility analysis, modal flexibility analysis, and potential energy distribution analysis were carried out. By studying the effects of geometric parameters, material parameters, surface parameters, and assembly parameters on weak parts, the most effective parameters for optimization were determined. The sensitive parameters were improved from type selection, surface technology, assembly process, and structural improvement. The optimization results showed that the modal flexibility of the weak modes has been reduced by 51.80%, 38.44%, 46.58%, and 27.21%, respectively, the modal flexibility ratios have been reduced by 17.27%, 5.19%, 27.11%, and 2.45%, respectively, and the 1st, 3rd, 4th, and 7th natural frequencies of the horizontal machining center have increased by 26.64%, 11.38%, 4.14%, and 4.55%, respectively. The effects of various parameters on the horizontal machining center were also discussed, which can provide reference for further optimization and research.