2. Mechanisms of plate-tool interaction under the blank holder

2.1 Qualitative analysis of the role of sheet metal roughness

6 schematically describes a metal-tool interface in the mixed pocket/plate lubrication regime generally present in the part's swaging zone; this point is adjusted by controlling the lubricant grammage (§ 1.2.1). It should be noted that this diagram is very general and valid for any contact under mixed lubrication conditions, both for mechanical parts and for shaping processes. The platens withstand the contact pressure imposed by the tool and are only separated from it by very thin films; this is the main source of friction and debris emission, the origin of which is the plastic deformation of the platens...