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A revolutionary concept in multilayer press technology has been developed that uses electromagnetic energy to heat the existing stainless-steel separator plates with a never-before dreamed-of accuracy and precision. The heating and cooling systems—embedded within a robust hydraulic press inside a vacuum chamber design—are controlled using a temperature feedback loop that guarantees perfect fidelity between the press recipe and the press result. This unique, electromagnetic induction technology helps make engineer's needs become a reality
The production of the first four-layer multilayer dates to 1960, which means the industry has manufactured multilayer PCBs for more than half of a century. Everyone involved with the PCB industry knows that the technical evolution of multilayer PCBs has been exponential from the first technical requirements to today’s. Current PCB requirements bring, collaterally, limits to the industrial-level manufacturing of state-of-the-art technologies.
The technical demands of modern PCBs have revolutionized almost all manufacturing processes from the multiple and complex chemical processes to mechanics, such as drilling, through the photoimaging of the circuit. However, if you look at the lamination process to cure today’s sophisticated resin composites, you can see that the evolution of the lamination presses has been slight in comparison. While today’s lamination presses are far better in many aspects than presses 59 years ago, press technology still uses the same method to produce the thermal energy (heat) and deliver the thermal energy that the resin composite needs to properly polymerize.
I want to introduce a new approach that uses a different way to generate thermal energy—and a new way to deliver it to the resins—that improves the lamination process for today’s materials requirements and new requirements in the future. While initially designed for multilayer PCB manufacturing, this technology can also greatly benefit laminate manufacturers, opening up new avenues of research into high-temperature composites and/or significantly shortened lamination cycles.
The InduBond lamination press utilizes a unique and novel way to produce the necessary heat to cure the laminates and multilayers—electromagnetic inductance. The standard and well-known press methods use one of the following technologies to generate the necessary thermal energy:
- Heating thermal oil and pumping it through a press platen
- Electrical heaters located right at the press platen
- A steam system through the press platens
All of these well-known systems heat the large thermal mass of the platens. The heat is then transferred to the panels being laminated via conductivity through the resin materials (i.e., the multilayer books to be laminated).
The novelty of this new technology, however, is that the thermal energy (heat) to cure the resin composites is produced directly at each of the stainless-steel separator plates that are between each multilayer panel in the press stacks. This thermal energy is transferred at the same time—with the same temperature magnitude and without any thermal conduction delays—to every panel of the lamination press stack. As the energy is induced very homogenously, the heat distribution has the highest uniformity possible in every position and direction of the press stack (X-, Y-, and Z-axes). Therefore, all of the layers of laminates inside the press reach the same temperature at the same time; there are no thermal transfer delays.
To make this possible, the laws of magnetism are used to induce high electrical currents that are transformed into thermal energy right at the material requiring polymerization. Because the heat is produced only at each stainless-steel separator plate of the stack, the technology can achieve extremely high temperatures and very rapid ramp-up rates with very high energy efficiency.
This article originally appeared in the October 2019 issue of PCB007 Magazine. Click here to continue reading or download the PDF to your library.