composite epoxy material

{{More citations needed|date=February 2022}}

Composite epoxy materials (CEM) are a group of composite materials typically made from woven glass fabric surfaces and non-woven glass core combined with epoxy synthetic resin.{{Cite web|last=Inc|first=ANSYS|title=Characterization of CEM-1 Boards|url=https://www.dfrsolutions.com/characterization-of-cem-1-boards|access-date=2022-01-20|website=www.dfrsolutions.com|language=en}}{{Cite web |last=Andy |date=2023-05-02 |title=Composite Epoxy Material {{!}} What You Need to Know - FR Fabric |url=https://frfabric.com/alkali-resistance/ |access-date=2023-07-20 |language=en-US}} They are typically used in printed circuit boards.{{Cite web|last=admin|title=FR1-FR3, CEM1-CEM3,FR4, Aluminum Flex CCL introductions {{!}} PCB Blog|url=http://caringcircuit.com/blog/ccl-fr1-fr-3-cem-1-cem-3-fr4-aluminum-flex/|access-date=2022-01-20|language=en-US}}

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.{{Cite web|date=2018-03-14|title=Why Is Cem-1 PCB Material still Popular in the Circuit Board Market ?|url=https://www.kingshengpcba.com/pcb-assembly/pcb-and-pcba/|access-date=2022-01-20|website=Printed Circuit Board Manufacturing & PCB Assembly - KingShengPCBA|language=en-US}}
• 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. Its color is white, and it is flame-retardant.{{Cite web|title=CEM-1 PCB|url=https://www.venture-mfg.com/cem-1-pcb/|access-date=2022-01-20|website=Venture Electronics|language=en-US}}
• CEM-4 quite similar to CEM-3 but not flame-retardant.
• CEM-5 (also called CRM-5) has polyester woven glass core.{{Cite web|last=PCB Directory Editorial Team|date=12 July 2019|title=What are Composite Epoxy Materials (CEMs)?|url=https://c-alley.com/|url-status=live|access-date=20 January 2022|website=PCB Directory|archive-url=https://web.archive.org/web/20220120134626/https://www.pcbdirectory.com/community/what-are-composite-epoxy-materials-cems |archive-date=2022-01-20 }}