Transfer of a friction model for cold bulk metal forming in industrial practice

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In the preceding DFG project, a friction model for cold extrusion with deterministic structured workpiece surfaces was developed. With the compression sliding test (CST), a model test for bulk metal forming, the parameters for the friction model were developed. With these parameters the friction behavior in a forward extrusion process can be represented very well and with accurate quality.Besides optimized friction formulation the new friction model has the advantage to consider surface parameters as field variable in finite-element-simulations. In the previous project the surface value Sq was chosen for validation and verification of the model.The results of the previous project seem to fulfill the requirement for the transfer in industrial practice. Therefore, the aims of this project are the transfer of the friction model to workpiece surfaces used in industrial practice. As well as the usage of surface parameters as field variable in finite-element-simulation the expansion of the friction model by dividing different contact conditions during the process are in focus of the project.The approach of the project is to determine the stresses and strains in chosen bulk metal forming processes followed by the evaluation of the varied friction model parameters. To evaluate the surface flattening and roughening, the topographies must be measured after and before each forming step. In a further work package the friction model will be expanded to different contact conditions between workpiece and tool. This expansion is necessary to obtain an universally valid friction formulation for bulk metal forming processes. On the basis of the project results the simulation quality of finite-element-simulations can be enhanced.