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

电磁成形工艺（EMF）使用磁力来形成导电金属板和型材。电动势的主要优点是非接触力传递以及高应变率。然而，EMF的使用受到限制，因为工作工具的耐用性低，并且用于其生产的设计指南的可用性有限。此外，目前用于加工线圈的生产方法极大地限制了工具适应相应成形任务的可能性。在该合作研究项目的第一个资助期内，铜合金CuCr1Zr获得了选择性激光熔化（SLM）的资格。通过SLM生产用于实际EMF研究的工作线圈。使用添加剂工作线圈的EMF实验已经显示出与由锻造铜合金制成的工作线圈相当的成形结果。集中于混合工作线圈的生产和使用的第一研究还表明，通过将薄铜层添加到钢基底上，与单片工作线圈相比，可以提高工艺效率。此外，在电动势过程中，作用在工作线圈上的热机械载荷进行了研究，这支持的设计准则的发展。单片和混合线圈概念的增材制造也是第二个资助期的重点。设计和制造复杂的单片多匝工作线圈是这些研究的目标之一。这就需要为EMF工艺和工具设计开发SLM扫描策略和仪器。由于增材制造工作工具的后处理或工作线圈匝之间的额外相互作用等限制，需要进一步调查，这在第一个资助期内无法完成。混合线圈概念的发展旨在实现电磁成形操作，这是不可能使用单片概念。复杂的材料转变是SLM研究的重点。成形过程的工艺和工具设计旨在分离电流传导和机械支撑的功能。这样，实现了局部电流集中和导电铜层的抑制塑性变形的新概念。

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.