Effects of Die Surface Roughness on Lubricating Conditions in the Sheet Metal Compression-Friction Test

Abstract

Sheet specimen of soft copper were subjected to plastic compression in plane strain, and then, to measure friction, one of the platens was slid in the direction of sheet width. Combined effects of die surface roughness and oil film thickness on friction are shown as the relations between friction and relative oil film thickness (ratio of mean oil film thickness to die surface roughness). With relatively rough dies, friction decreases with increase in sliding speed, and a corresponding decrease in conformance of the workpiece to the die was observed.

Effects of entraining velocity of lubricant and sliding velocity on friction behavior in stainless steel sheet rolling

“…To date, only one attempt to separate the effects of the two factors on friction has been made in the sheet compression process at low velocity [5] , and there has been no trial at high velocity, which is experienced frequently in the actual forming process. The effects of the two factors on friction at high velocity may be largely different from that at low velocity because the contact situation and thermal condition are very different.…”

The effect of roll roughness on the rolling parameters during cold rolling of an aluminum alloy

“…The surface roughness of the tool has a profound influence on tribological phenomena [6]. They use dies of 0.02, 0.16 and 1.2 m R max surface roughness, respectively, and soft copper as the work piece.…”

The effect of roll roughness and lubricant viscosity on the loads on the mill during cold rolling of steel strips

“…Using dies of roughness, varying from 0.02 to 1.2 m R max , pressures of 400-460 MPa and speeds up to 19 mm/s, Mizuno and Hasegawa [15] report that the mean friction stress with the roughest die is four times that of the smoothest. Employing a ball-on-disc type equipment, Andersson and Salas-Russo consider the changing frictional mechanisms caused by increasing surface roughness, and write that "the importance of this phenomenon may be compared with that of structural fracture, .…”