In order to select the correct power it is necessary to first calculate the thermal energy required to raise the material to the required temperature in the time allotted. This can be done using the heat content of the material which is normal expressed in kW hours per tonne, the weight of metal to be processed and the time cycle.Rudnev, p. 22. Once this has been established other factors such as radiated losses from the component, coil losses and other system losses need to be factored in. Traditionally this process involved lengthy and complex calculations in conjunction with a mixture of practical experience and empirical formula. Modern techniques use finite element analysis and other computer-aided manufacturing techniques, however as with all such methods a thorough working knowledge of the induction heating process is still required. When deciding on the correct approach it is often necessary to consider the overall size and thermal conductivity of the work-piece and its expansion characteristics in order to ensure that enough soak time is allowed to create an even heat throughout the component.
