Tribosystems for cold forming processes based on volatile lubricants and laser structured surfaces

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The proposed research project submitted by the Institutes for Metal Forming Technology, Interfacial Process Engineering and Plasma Technology as well as Laser Technologies belonging to University of Stuttgart will lead to entirely novel tribological systems for cold forming processes. Such tribosystems shall be developed for specific surface pressure levels and variably acting friction shear stresses by using laser prepared surfaces on the tool side, and a solid, liquid or gaseous volatile intermediate.The first time phase of the research project contains physical and knowledge-oriented fundamental research on characterization of volatile lubricating media applied in solid or liquid state ((N2 or CO2) on previously laser structured semi-finished tool surfaces. At first, the investigations shall be accomplished on exemplary laboratory tests (strip drawing test and autoclav). Subsequent funding periods should deal with investigations on real sheet and bulk metal forming processes and its application on semi-finished part or tool. Long-term goal of the project is thus to provide a validated tribological system, based on laser structured surfaces, which were wetted just before or during forming process, with an intermediate that volatilizes without any residues after the process. The scientific claim of the collaboration of the Institutes of the University of Stuttgart therefore is referred to the announcement of this program in joint development of a high performance of such tribosystems for metal forming technology under real friction conditions, which later shall be characterized for some exemplary processes of sheet and bulk metal forming. The gained scientific knowledge is expected in the field of modified process control in metal forming technology on novel, more suitable topologies of the tool surfaces as well as on a deeper insight of distribution and wetting mechanisms in interstice between part and tool of volatile lubricating intermediates. Preliminary tests have shown that the application of CO2 in solid state reduces the friction in a significant manner and can work as a temporarily acting, residue-free and environmentally neutral (CO2 is taken from air) lubricant.