Friction measurement apparatus for sheet metal forming

Friction at the tooling-workpiece interface is very important in sheet meta l forming operations. Accurate knowledge of friction at such interfaces is needed for process design and analysis, numerical process simulation and va lidation and control of forming processes. Two physical models or friction simulators, based on the stretching of a strip around a pin, were developed to characterize sheet metal forming friction. In contrast to other test ap paratus which use measurements of strain to infer friction forces, these ap paratus use direct measurements of forces. Effects of strain, stretching sp eed, lubrication, pin radius and wrap angle on coefficient of friction were determined. (C) 1999 Published by Elsevier Science S.A. All rights reserve d.