Composite epoxy materials (CEM) are a group of
composite material
A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or ...
s typically made from woven glass fabric surfaces and non-woven glass core combined with
epoxy
Epoxy is the family of basic components or cured end products of epoxy resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide functional group is also coll ...
synthetic resin
Synthetic resins are industrially produced resins, typically viscous substances that convert into rigid polymers by the process of curing. In order to undergo curing, resins typically contain reactive end groups, such as acrylates or epoxides. ...
. They are typically used in
printed circuit board
A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in Electrical engineering, electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a L ...
s.
There are different types of CEMs:
* CEM-1 is low-cost, flame-retardant, cellulose-paper-based laminate with only one layer of woven glass fabric.
* CEM-2 has cellulose paper core and woven glass fabric surface.
* CEM-3 is very similar to the most commonly used PCB material,
FR-4
FR-4 (or FR4) is a NEMA grade designation for glass-reinforced epoxy laminate material. FR-4 is a composite material composed of woven fiberglass cloth with an epoxy resin binder that is flame resistant (''self-extinguishing'').
"FR" stands fo ...
. Its color is white, and it is flame-retardant.
* CEM-4 quite similar as CEM-3 but not flame-retardant.
* CEM-5 (also called CRM-5) has polyester woven glass core.
See also
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*
References
Composite materials
Electronic design
Fibre-reinforced polymers
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