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PCB007-Oct2019

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32 PCB007 MAGAZINE I OCTOBER 2019 netic field lines of the magnetic field generated by the coil penetrate the stainless-steel sepa- rator plates, inducing high electrical currents that generate heat on each single separator plate of the press stack. That happens without any electrical or physical contact (wireless), thermal oil, or steam—just induction. The generated heat on each stainless-steel separator plate is transferred immediately to the laminate in contact above and below. This internal and quick thermal transfer makes pos- sible a no-delay energy transfer throughout the entire stack height while the thermal in- ertia is very low. A dummy panel with exactly the same material and physical properties as the laminate and with embedded temperature sensors is used to track the temperature of the material to be laminated in real time. No parts other than the stainless-steel separator plates are actively heated, which results in high elec- tric efficiency; the heat is created internally on the press stack (Figure 6). In conventional lamination press technolo- gies where the heavy mass of the platens is heated up to then transfer that thermal energy from the platens to the panels (from outside to inside), an indirect source of energy is needed to heat up those big-mass platens. Convention- al technologies typically use thermal oil, elec- trical heaters, or steam. For thermal oil systems, the platens become mechanically complex due to the need for chan- nels where the oil must flow to pump the heat into the platens. For electrically heated sys- tems, many ohms of resistance at high power are required to exchange heat via these embed- ded cartridge heaters into the big-mass platens. Both methods require huge amounts of pow- er to heat up the platens that are mechani- cally connected to the main structure, causing high heat conduction losses. Because the heat is created in the external platens, the thermal energy has to travel by conduction from exter- nal platens to the material, passing through all separator plates and laminates. Dielectrics are inherently low thermal conductivity materials, which results in thermal conductivity delays (Figure 7). Figure 6: InduBond X-Press schematic cross-section. Figure 7: Conventional press technology schematic cross-section.

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