Composite epoxy material explained

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.^{[1] [2]} They are typically used in printed circuit boards.^[3]

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.^[4]
• 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.^[5]
• CEM-4 quite similar to CEM-3 but not flame-retardant.
• CEM-5 (also called CRM-5) has polyester woven glass core.^[6]

Notes and References

1. Web site: Inc. ANSYS. Characterization of CEM-1 Boards. 2022-01-20. www.dfrsolutions.com. en.
2. Web site: Andy . 2023-05-02 . Composite Epoxy Material What You Need to Know - FR Fabric . 2023-07-20 . en-US.
3. Web site: admin. FR1-FR3, CEM1-CEM3,FR4, Aluminum Flex CCL introductions PCB Blog. 2022-01-20. en-US.
4. Web site: 2018-03-14. Why Is Cem-1 PCB Material still Popular in the Circuit Board Market ?. 2022-01-20. Printed Circuit Board Manufacturing & PCB Assembly - KingShengPCBA. en-US.
5. Web site: CEM-1 PCB. 2022-01-20. Venture Electronics. en-US.
6. Web site: PCB Directory Editorial Team. 12 July 2019. What are Composite Epoxy Materials (CEMs)?. live. 20 January 2022. PCB Directory. https://web.archive.org/web/20220120134626/https://www.pcbdirectory.com/community/what-are-composite-epoxy-materials-cems . 2022-01-20 .