The lamination process is a critical part of manufacturing printed circuit boards. Lamination is the process of building up successive layers of material and bonding those layers together. The Lamination process occurs at the point in fabrication when the inner layers (cores), outer layer foils and prepreg are stacked, heated, and pressed into a composite, or a finished circuit board. Lamination requirements will vary depending on materials used.
The basic material consists of sheets of woven fiber glass, pre-impregnated with epoxy resin. This is most often referred to simply as prepreg. Copper foils cover the top and bottom of the stack. The internal cores or substrates, which contain the copper traces etched to the customer’s requirements, are also separated with pre-preg.
The cores, pre-preg, and foils are securely aligned onto pins attached to a lay-up fixture. Then the stack is “staked” in place using rivets that are heated to hold the stack together and minimize shifting. Now it is ready for lamination.
Once loaded in the press the process is run via the presses controller. The controller executes the sequences of drawing a vacuum, heating up the stack, engaging the ram to apply pressure, and when to allow the stack to cool at a predetermined rate.
The InduBond lamination presses used at GreenSource Fabrication also have the capability of reaching temperatures to facilitate the fusion bonding of Teflon and other non-reinforced materials. Additionally, the InduBond system consumes 80% less energy than a conventional hot oil press, making it very "Green"!