1. A large current discharge is directed through a coil. The coil has been placed inside another shape.
2. The discharging current creates a magnetic field. In the nearby sheet of metal an opposing magnetic field is induced. The result is that the two magnetic fields oppose and a force moves the sheet away from the coil.
3. Over a period of time the part is deformed, often to the shape of a mandrel, or other form.
• Capacitor banks are used to accumulate charge for larger discharges.
• The part is formed to a mandrel that has a negative image of the part.
• The method generates pressures up to 50 Kpsi creating velocities up to 900 fps, production rates can climb to 3 parts a second.
• Generally there are three methods of magnetic forming,
• Swaging - An external coil forces a metal tube down onto a base shape (tubular coil).
• Expanding - an inner tube is expanded outwards to take the shape of an outer collar (tubular coil).
• Embossing and Blanking - A part is forced into a mold or over another part (a flat coil) - This could be used to apply thin metal sheets to plastic parts.
- allows forming of metals to any material
- no contact eliminates many requirements such as lubricants, heat dissipation, surface repair, etc.
- high production rates (typically a few seconds)