Basic principle of high frequency power supply in blister packaging

Put the workpiece into the inductor (coil), when an alternating current of a certain frequency is passed into the inductor, an alternating magnetic field is generated around it. The electromagnetic induction of the alternating magnetic field produces a closed induced current-eddy current in the workpiece. The distribution of the induced current on the cross section of the workpiece is very uneven, and the current density on the surface of the workpiece is very high and gradually decreases inward. This phenomenon is called the skin effect. The electric energy of the high-density current on the surface of the workpiece is converted into heat energy, which increases the temperature of the surface layer, that is, surface heating is realized. The higher the current frequency, the greater the current density difference between the surface layer and the inside of the workpiece, and the thinner the heating layer. Surface quenching can be achieved by rapid cooling after the temperature of the heating layer exceeds the critical point temperature of the steel.