Reduction of adhesion formation during forming and blanking by influencing thermoelectric currents externally

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In the DFG project "Lubricant-free forming by affecting thermoelectric currents", adhesion formation during dry blanking could be reduced by up to 30% by means of an external constant compensation current at an adapted level. Within the scope of this project, this novel method for reducing galling is now to be further developed for industrial implementation, so that it can be used in future in every forming and cutting process with even higher quantity reductions. Since temperatures and thermocurrents occurring in the tool are primarily determined by the thermoelectric behavior and the mechanical properties of tool and sheet materials, the existing database will first be expanded to include new materials and parameters. In experimental investigations of the processes precision and normal blanking as well as deep drawing with different material combinations, all relevant process variables are measured both dry and under different lubrication conditions. On this basis, the course and level of the external compensation current are adapted to the respective process in order to achieve the greatest possible adhesion reduction. An analytical model is derived from the combination of the findings obtained with those of the previous project. This approach enables the selection of a compensation strategy adapted to the respective process without knowledge of complex interrelationships. Known data such as velocity profiles, force curves, mechanical and physical material properties and selected process parameters are used as input variables. Together with a universal electrical contacting system for active elements as well as sheet metal, which is to be developed, this method can be implemented easily and cost-effectively in new and existing industrial tools in the future. Finally, the improved potential of this method is demonstrated by its use in two industrial tools. Thereby, the interaction between lubricant, current and process temperature opens up new fields of research in the field of lubricated tribological systems.