Inductive magnetic forming of pipes

Parallel capacitors charged to a very high voltage is supplied. The stored energy is then released from the capacitors and conducted to the process coil [1], where a high intensity magnetic field is generated. The coil induces eddy currents in the workpiece [2], which produce an additional magnetic field. The two magnetic fields oppose each other and create such a strong repulsive force between the coil and the workpiece that the workpiece is deformed by plastic deformation [3].

There are two approaches for forming tubes by this method. Both a die [4a] and the coil placed within the workpiece, or the workpiece is enveloped by the coil to join the workpiece with an insert [4b].

The process uses rigid or expandable and insulated coils and these must withstand the repelling force. The expandable coils are expensive and are beneficially used when large amounts of energy are needed.