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Materials

Most Commonly Used

CEM-1- Made from paper and woven glass which is impregnated with an epoxy resin, this material is good for punching. Improved electrical and physical properties make it suitable for both consumer and industrial electronics.

CEM-3- A composite made of dissimilar core materials, CEM-3 utilizes nonwoven fiberglass surfaced with woven fiberglass sheets, both impregnated with epoxy resin. Higher in cost than CEM-1, CEM-3 is better suited for plated through holes and has a strong history of use in entertainment, autos and home computers.

FR-2- Good for punching, cheap and flame-resistant, this material can be used in a host of applications where dimensional stability is not required. (i.e. toys and calculators).

FR-4- Constructed of woven fiberglass clothes which are impregnated with epoxy resin or epoxy resin blend, the outstanding electrical, mechanical and thermal properties of FR-4 make it an excellent matrial which can be useful in a wide range of applications (i.e. automotive, computers, servers, industrial applications, telecommunications, aerospace...).

Non-Flame Retardant

G-10 (Epoxy Woven Glass)
XXXPC (Phenolic Cotton Paper)
CEM-2 (Epoxy Cotton Paper/Woven Glass)
CRM-6 (Polyester Woven Glass/Mat Glass)
CRM-8 (Polyester Mat Glass/Glass Veil)
CEM-4 (Epoxy Woven Glass/Mat Glass)

Flame Retardant

FR-2 (Phenolic Cotton Paper)
FR-3 (Epoxy Cotton Paper)
FR-4 (Epoxy Woven Glass)
FR-5 (Epoxy Woven Glass)
FR-6 (Polyester Mat Glass)
CEM-1 (Epoxy Cotton Paper/Woven Glass)
CEM-3 (Epoxy Woven Glass/Mat Glass)
CRM-5 (Polyester Woven Glass/Mat Glass)
CRM-7 (Polyester Mat Glass/Glass Veil)

Base Material Characteristic Awareness

Most of these base materials do comply with the RoHS directive, but another consideration is the properties of the material. There are four essential characteristics to look at in a material.

Coefficients of Thermal Expansion (CTEs)
Decomposition Temperature (Td)
Glass transition temperature (Tg)
Moisture Absorption
Another quality to take into account that deals with the laminate more, is the time to delamination performance.  

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