Development and manufacturing of optimized working coil windings for electromagnetic forming employing additive manufacturing techniques

点击翻译按钮获取中文摘要

The electromagnetic forming process (EMF) uses magnetic forces for forming of electrically conductive metal sheets and profiles. The main advantages of EMF are the non-contact force transmission as well the high strain rates. However, use of EMF is restricted because of low durability of the working tools and limited availability of design guidelines for their production. Additionally, the currently applied production methods for working coils considerably limit the possibilities for adapting tools to the respective forming task.During the first funding period of this collaborative research project the copper alloy CuCr1Zr was qualified for Selective Laser Melting (SLM). Working coils for practical EMF investigations were produced via SLM. EMF experiments using additive working coils have shown forming results which are comparable to working coils made of a wrought copper alloy. First investigations focusing on the production and use of hybrid working coils have also shown that by additive application of a thin copper layer to a steel substrate, the process efficiency can be increased compared to monolithic working coils. Additionally, the thermomechanical loads acting on the working coils during the EMF process were investigated, which support the development of design guidelines. Additive manufacturing of monolithic and hybrid coil concepts is also the focus of the second funding period. Design and manufacturing of complex monolithic multi-turn working coils is one of the goals of these investigations. This requires the development of SLM scanning strategies and instruments for EMF process and tool design. Because of restrictions e.g. by post-processing of additively manufactured working tools or additional interactions between the turns of working coils there is demand for further investigations, that could not be completed in the first funding period. The development of hybrid coil concepts aims to realize electromagnetic forming operations, which are not possible using monolithic concepts. The complex material transitions are the focus of SLM investigations. The process and tool design for the forming process aims at a separation of the functions conduction of current and mechanical support. This way new concepts for a local current concentration and a suppressed plastic deformation of the conductive copper layer are realized.