Effect of contact area on friction force in sheet metal forming operations

There are a number of ways to reduce friction such as lubrication, improving the surface roughness, reducing the acting surface pressure, surface texturing and reducing the contact area. In this study the effect of the contact size and surface pressure on process limits of a forming process is investigated. For this purpose draw-bending of U-Channel is subjected for testing of the effect of surface reduction by means of micro surface texturing and macro structuring. The results show that micro surface texturing and macro structuring of forming tools can reduce the friction force in forming processes. A combination of these approaches can be applied in tooling design to minimize the friction forces and ultimately realize a lubricant-free forming process.