Studies on the reproducibility of the magnetic pulse welding in the case of an asymmetric impact

该项目的主要目标是提高MPW的再现性。从目前的技术水平和我们自己的前期工作来看，表面处理对焊接区重复性和下部曲线形成的影响是显而易见的。实验表明，垂直于焊缝方向的干涉轮廓对焊接的影响很大，要想重复使用MPW，MPW焊接窗口的下部曲线必须是可预测的。为此，必须将曲面合并到下部焊接曲线的计算中。焊接下部曲线必须补充曲面的系数。在所提出的方案中，特别是粗糙度及其相对于焊接方向的取向被考虑为表面效应。在SPP 1640项目A5(Darmstadt)中调查的更多地表影响也应该被考虑和整合。冲击压力所需的碰撞速度将在项目A5的模拟结果的一侧和与有机玻璃靶材和高速PSD传感器的实验装置的另一侧使用。由于不同的前处理，可以显示出更光滑的靶面引导到焊接区的早期开始，而粗糙的表面引导到较宽的焊接区。为了解释这种影响，工作假设是，在小碰撞角期间产生的“薄”射流足以在焊缝开始时产生更光滑的表面，以清洁光滑的表面并启动焊接过程。在焊接过程结束时，当碰撞角很大时，在上面留下焊接窗口，垂直粗糙度局部减小碰撞角，延长焊接过程，因此，本方案的进一步目标是通过梯度增加表面粗糙度，使焊接过程从光滑的表面开始，在粗糙的表面结束。为了实现这些目标，计划与达姆施塔特(PTU)的A5项目以及开姆尼茨(IWW)的A8项目进行密切合作。

The main objective of the project is to increase the reproducibility of the MPW. The influence of surface pretreatment on the reproducibility and to the formation of the lower curve of the weld area is clear from the state of the art and our own preliminary work. Our experiments show the strong influence of interfering contours perpendicular to the weld direction.To use MPW reproducibly, the lower curve of the welding window for MPW must be predictable. For this purpose, the surface must be incorporated into the calculation of the lower welding curve. The welding lower curve has to be supplemented with a factor for the surface. In the proposed project, especially the roughness and its orientation with respect to the welding direction are considered as a surface effect. More surface influences that are investigated in the SPP 1640 project A5 (Darmstadt), should also be considered and integrated. The collision speed required for the shock pressure will be used at the one side from the simulation results of the project A5 and at the other side from the experimental setup with the Plexiglas target and the high-speed PSD sensor.Due to the different pre-treatments it could be shown that a smoother target surface guides to an early beginning of the welding zone and a rough surface guides to a wide welding zone.For the explanation of this effect, the working hypothesis is that "thin" jet is sufficiently a smoother surface at the beginning of the weld produced during the small collision angle , to clean a smooth surface and to initiate the welding process. At the end of the welding process when the collision angle is so large that the welding window is left after above, a perpendicular roughness reduce the collision angle locally and the welding process is prolonged.Thus, a further aim of the project is increase the roughness of the surface by a gradient so, that the welding process starts with a smooth surface and ends at a rough surface. The welds will be more reproducible and the weld length will be constant high.To achieve the objectives, a close cooperation is planned with both the A5 project from Darmstadt ( PTU) as well as with the project A8 from Chemnitz ( IWW) .