Prepreg
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Prepreg is an abbreviation for "pre-impregnated composite fibers." In the world of Printed Circuit Boards (PCBs), this refers to glass fiber fabric pre-impregnated with a resin composite. The resin helps to bond the fabric during heating and subsequent cooling, creating a robust, insulating layer between the copper layers of a PCB.
Usage & Manufacturing
Similar to the core layer of a PCB, prepreg serves an insulating function, which is why it is also referred to as a dielectric. However, unlike the core layer, it is merely the adhesive layer between two core layers onto which the traces have already been applied. When the PCB undergoes a high-temperature lamination process, the resin in the prepreg melts, flows, and subsequently crosslinks upon cooling, creating a strong bond between the adjacent copper layers. This ensures the mechanical and electrical integrity of the PCB.
Types of Prepreg
There are various types of prepregs, differing in thickness, resin content, and flow properties. Choosing the right prepreg depends on the specific requirements of the PCB design, including the desired final thickness of the PCB, the number of layers, and the specific electrical properties. It is important to consult with your PCB manufacturer to ensure the correct type of prepreg is selected for your project.
