Prediction of dynamics of modified machine tool by experimental substructuring

Abstract

Until now the methods of experimental substructuring are rarely adopted in the machine tool sector, except for receptance coupling of tools and tool holders. In this paper, the methods are adopted to predict a general modification of a machine tool structure by coupling experimental and numerical models. This approach seems appropriate, since most design changes of machine tools affect only some part of the structure. Additionally, single components of a machine tool are easier to simulate than the complete machine tool, since they include less joints, which are usually difficult to parameterize. This contribution evaluates the proposed method, when it is applied to a single axis test bench. The slide is taken as the modified component—thus its dynamics are modeled analytically—and the remaining assembly is modeled experimentally. Particular emphasis is put on the modeling of the interfaces of the linear guides connecting the slide to the frame. Both a fixed connection between slide and frame and a linear spring-damper joint are adopted. Moreover, the dynamics of the assembly are predicted, for different positions of the slide. As a reference, the dynamics of the test bench are measured, when the slide is mounted.