Bulk microforming of small metal components from strip

• Applicant: Professorin Dr.-Ing. Marion Merklein, since 10/2016
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: from 2008 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 98772263

In the first project phase, material and relevant process performances for a single-stage microforming process from metal strip have been studied. A full forward extrusion process and a progressive die have been designed and realized to this end. In order to reduce undesired strip deformation, on the basis of previous studies and variant calculations, the geometry of the strip has been optimized by means of adequate cut-outs.Starting from these results, in the second phase, the basic process knowledge should be expanded considering increased complexity of the progressive forming steps. Aiming to the definition of general process-design guidelines, it is necessary, to determine the influences on the formed workpiece, to analyze the interactions between formed workpiece and supporting strip as well as to consider the microforming effects. Besides the study of the workpiece properties in relation to the manufacturing process, one focus of the study can be identified in the accumulation of material for subsequent forming stages. This aims not only to the maximization of the workpiece volume, but also to the optimized reduction of undesired strip deformations improving at the same time the material utilization. Different options of material flow control are considered. A first possibility is the adjustment of the friction condition between contact surfaces e.g. by means of abrasive blasting of the upper part of the strip. Geometrical modifications of the tooling are analyzed in parallel, adapting the punch contact surface and integrating the blank holder with a ring indenter. The typical size-effects effect of microforming will be studied by scaling the geometry. The manufacturing of a cup defines the process goal and together with the preparatory and final cutting operations represents the complete progressive die process. Detailed information on the effects of different forming processes can be achieved by the comparison of the single-stage cup forward extrusion process with a two-stage combination of full-forward and cup-forward extrusion process. The experiments will be conducted both experimentally and with FE-simulations, defined by applying the methods of design of experiments.The results obtained within the project should finally enable the definition of both process window and process limits, deriving generally valid recommendations for the design. Generally valid basics of multi-stage microextrusion processes from strip are to be achieved by the planned studies.

• DFG Programme: Research Grants
• Ehemaliger Antragsteller: Professor Dr.-Ing. Ulf Engel, until 10/2016