Do we need to do power and frequency calibration after setup and how often should we do that?
If you're getting the same temperature on the part time after time, year after year, then your process is under control.
Power and frequency should be chosen by your induction heating supplier who are the best-suited to guide you to the right power and frequency for the application. Today's power supplies all have benefited vastly from the advancements in semiconductor technology. Everything is digital. These systems do not lose calibration over time, but there are some applications that may warrant verification that the power supply is still under calibration. Those types of applications, there are facilities available to calibrate the power supply. Your manufacturer will certainly be one of them. Or you could devise your own way of making sure that the heat produced in the part for a typical cycle of heat time is exactly the same. Because the output of any induction heating system is heat. So if you're getting the same temperature on the part time after time, year after year, then your process is under control.