Felix Flegler¹, Peter Groche¹, Tim Abraham², Günter Bräuer²; ¹TU Darmstadt Institute for Production Engineering and Forming Machines, ²Fraunhofer Institute of Surface Engineering and Thin Films IST

Dry forming processes are associated with major challenges, especially when it comes to aluminium as a material. The high tendency to adhesion to common tool materials makes it possible to eliminate lubricants only with major losses in process quality and robustness. Coatings based on amorphous hydrocarbons (a:C-H) can significantly reduce wear behavior. In previous investigations, a reduction of the sheet roughness based on the native mill-finish surface showed a significant improvement with regard to the friction and wear behaviour in the strip-drawing test. These tests are now transferred to a real work piece. First, the different zones of the deep drawing process are modelled in the strip-drawing test. While in the area of the drawing ring, the smooth sheet surface is virtually wear-free and characterized by a low coefficient of friction, in the blank holder area adhesions of aluminum are observed despite significantly lower tribological loads.