Induction Heating is a process where a metal object, magnetic or non-magnetic, is placed in a varying magnetic field, technically known as Eddy Currents. Imagine you have a round copper coil and then you pass an alternating current through this coil. That would generate a magnetic field within the coil.
Then imagine you interrupt this field by inserting a piece of metal (a solenoid in the picture below), inside of this coil. The magnetic field would begin to wrap itself around the workpiece at a very high rate. How high a rate depends on the frequency of the applied RF field. So, for instance, if the RF frequency is 50kHz, then the field will wrap itself around the workpiece 50 times per second.
As the field continues to “spin” around the metal, it begins to generate heat within the workpiece. How? Because every metal has a certain amount of resistance within it, and this resistance effect causes the applied field to create friction within the metal. This in turn generates heat on the surface of the metal, commonly known as a Skin Effect. Depending on how long you leave the field, the heat will begin to travel through the metal by conduction.
The cool part is that the Coil is water-cooled while the metal piece gets hot!
These are some of the coils we have designed and built for a variety of applications. (Photos courtesy of CEIA USA.) Our Master Coil Makers design coils that are optimized to heat parts of all shapes and sizes, for brazing, heat treating, etc.