Effect of surface topography of workpiece on pressure dependence of coefficient of friction in sheet metal forming

摘要

In the previous sheet draw tests of Al-Si alloy and aluminum having a dull surface, the authors found that the coefficient of friction was constant in the lower pressure range, whilst in the higher pressure range, it decreased with increasingpressure and the relationship was qualitatively interpreted from results of the direct observation of contact behavior. In the present work, the pressure dependence is examined, changing the surface topography of workpiece by prerolling to differentflattening degrees of surface asperities. From the results of direct observation of contact behavior obtained by making use of a newly developed fluorescence measurement method, the contact model can be interpreted 3-dimensionally for better surfacecontrol.