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34 PCB007 MAGAZINE I OCTOBER 2019 to the M3 (the separator plates). The amount of energy needed, under ideal conditions, to heat both systems from ambient temperature 25°C (77°F) to 220°C (430°F) is shown here: M1 (platen mass) is ~70 kg; M3 (mass of stainless-steel separator plates) is ~4 kg; the specific heat of iron is 0.45 KJ/kg·K. For the traditional technology system: Q = (220°C - 25°C) x (70 kg + 4 kg + 70 kg + 4 kg) x (0.45 KJ/kg·K) = 12,987 KJ For the electromagnetic inductance technology: Q = (220°C - 25°C) x (4 kg + 4 kg) x (0.45 KJ/kg·K) = 702 KJ In this example, the traditional method uses 18.5 times more energy than the electromag- netic inductance system. Plus, this example does not consider other large real losses like the energy transferred to other unnecessary large masses in physical contact, such as the links of the platens and guides to the main press structure. Preparation of the Lamination Press Stack Because this electromagnetic induction technology indirectly heats up each individu- al stainless-steel separator press plate—with- out the large thermal transfer delays of con- ventional technologies—it is not necessary to make a multi-opening press, although this is possible. This technology allows one to place all panels in a single-opening press. The lamination press stack is built alter- nating conventional stainless steel separa- tor plates with the laminate material, as in the well-known standard process. There can be just one panel in the opening or approxi- mately 30 panels in the whole opening capac- ity (Figures 10a and b). The separator press plates are the same standard stainless-steel separator plates used in a traditional lamina- tion press. During stackup, the operator places a dum- my panel with a minimum of 2-4 thermo- couples for the temperature feedback control system in the middle of the stack. Those tem- perature sensors will monitor the real tempera- ture of the laminate so that the control system can follow the programmed temperature pro- file (Figure 11). Figure 10a and b: Lamination press stack with conventional stainless-steel separator plates. a b Figure 11: Dummy panel with the four thermocouples embedded.