Re: magnetic pulse spot welding
Posted by Bert on 3/3/2020, 10:01 am, in reply to "Re: magnetic pulse spot welding"
Thanks for the response. I understand conventional resistance spot welding. What I want to explore is magnetic pulse spot welding steel to steel. This is similar to explosive welding rather than conventional resistance spot welding There is some limited publications on Al to Cu sheet welding using 1 to 6 turn coils. I want to know how to drive one of the sheets, the flyer plate, across the space gap to impact weld it to the second sheet. How do I generate the magnetic pulse to drive the flat coil. It looks like a similar process to coin shrinking except using a flat coil rather than a round one.
You're correct - in this process a flat "flyer plate" is electromagnetically repelled by a flat work coil, accelerating until it slams into the other plate. The process is called "Magnetic Pulse Welding", and is similar in principle to explosive bonding. The theory is that, if you can couple enough kinetic energy into the flyer plate, you can achieve an explosive weld/bond at the interface when it slams into the other plate. It is sometimes done in a vacuum to prevent air resistance from slowing down the flyer plate.
However, using a pulsed magnetic field to repel and accelerate a steel flyer plate is difficult due to steel's higher electrical resistivity. It's much harder to induce enough electric current into the flyer plate without using 10's to 100's of kilojoules of capacitor bank energy. This requires using a large high-voltage, high-energy pulse capacitor bank, a high-power, high-voltage DC charging supply, a high-current switch to handle hundreds of kilomperes, and a massive copper work coil, usually embedded in epoxy for rigidity. Unfortunately, these are all expensive, large, hard-to-get items. This is simply not something you can easily do at home on a modest budget.
For more information about the process, see: