Dynamic Interaction Between Precision Machine Tools and Their Foundations

Abstract

The manufacturing accuracy of modern machine tools strongly depends on the placement of the machine tool structure on the factory’s foundation. Civil engineering knows a variety of foundation types and factory planners must carefully consider local circumstances such as the size and the properties of the regional subsoil as well as the individual requirements of machine tools. Two of the major reasons for the effect of the foundation onto the machining accuracy are the added stiffness and the increased mass from the installation site’s foundation. A change of these characteristics greatly affects the dynamic characteristics of the overall machine tool and therefore also the machining dynamics. Although some general rules and guidelines exist for the design of foundations, their dynamic interaction with the supported precision machine tool structures is not well understood yet. This paper presents a series of measurements on two different types of machine tool foundations and highlights the characteristic differences in their dynamic interaction. It also proposes a novel approach to validate the conclusions with the use of foundation and machine tool scale models. These results can serve factory planners of precision targeting shop floors as a valuable guide for deciding on a suitable foundation for lowering the individual machine tool vibrations and/or reducing the dynamic interaction between closely located machine tools.