Workpiece-fixture static friction under dynamic loading

Workpiece fixturing for machining operations often relies on friction to pr event workpiece motion. Since most machining operations involve dynamic loa ds, a better understanding of the influence of such loading on workpiece-fi xture contact friction is desirable. This paper presents the results of an experimental investigation of the effects of normal preload force, vibratio n amplitude and excitation frequency on the static friction between cast al uminum 357 workpiece material and oxide coated AISI 1144 steel fixture mate rial. A friction tester capable of simulating normal and in-plane dynamic l oads was designed and built for the study. Response surface analysis of the experimental data reveals that dynamic loading significantly influences wo rkpiece-fixture static friction. Possible explanations for the observed eff ects are given. (C) 1999 Elsevier Science S.A. All rights reserved.