The Bulging of Bolted Guideways

Abstract

As bolted joints affect the overall accuracy and stiffness of a machine tool, their behaviors have always been important to consider in a machine design process. The bulging phenomenon of a bolted guideway needs to be investigated under different loading conditions. A considerable amount of research has been reported on bolted joints; however, none is focused on the bulging of a bolted guideway. In this article, the bulging of three types of guideways is studied using the finite element method and the results are verified by the experiments using capacitance sensors. It turns out that the bulging occurs in such a way that the lower portion of a guideway expands while the top portion around the bolt sinks in the order of micrometers. The results would help the machine tool builders to reduce or eliminate the errors induced by the bulging effect from their products. The results are also useful to other applications of bolted joints where three-dimensional deformation occurs.