High-speed Direct Laser Interference Patterning of sheet metals for friction reduction in deep drawing processes

Friction has a dominant influence on manufacturing processes. In deep drawing of sheet metals, lubricants are regularly used to reduce friction forces. Significant production costs originating from supply, application, removal and disposal as well as the negative environmental consequences of using lubricants promote extended research on lubricant free deep drawing processes and tools. A combination of macro-structuring in the flange area and micro-structuring of ta-C layers at the pulling edge radius of deep drawing tools is identified to compensate the loss of tribological functions. Surface texturing of semi-finished sheet metals supports the friction reduction by minimizing the contact area to the deep drawing tool. In this study, a new concept for sheet metal texturing is presented. Using Direct Laser Interference Patterning, periodic surface patterns are fabricated at high fabrication speeds and their influence on the friction behaviour is tested by means of draw bend test. The results show minimal friction for ta-C covered draw bend tools and sheet metal structuring in bending direction.