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

• Applicant: Professor Dr.-Ing. Stefan Böhm
• Subject Area: Production Automation and Assembly Technology
• Term: from 2014 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 264255196

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) .

• DFG Programme: Priority Programmes
• Subproject of: SPP 1640: Joining by Plastic Deformation