FR-2 (Flame Resistant 2) is a

NEMA The National Electrical Manufacturers Association (NEMA) is the largest trade association of electrical equipment manufacturers in the United States. Founded in 1926, it advocates for the industry, and publishes standards for electrical product ...

designation for synthetic resin bonded paper, a

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 ...

made of

paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distributed ...

impregnated with a plasticized phenol formaldehyde resin, used in the manufacture of

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. Its main properties are similar to NEMA grade XXXP (MIL-P-3115) material, and can be substituted for the latter in many applications.

Applications

FR-2 sheet with copper foil lamination on one or both sides is widely used to build low-end

consumer electronic Consumer electronics or home electronics are electronic (analog or digital) equipment intended for everyday use, typically in private homes. Consumer electronics include devices used for entertainment, communications and recreation. Usually ...

equipment. While its electrical and mechanical properties are inferior to those of epoxy-bonded fiberglass,

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 ...

, it is significantly cheaper. It is not suitable for devices installed in vehicles, as continuous vibration can make cracks propagate, causing hairline fractures in copper circuit traces. Without copper foil lamination, FR-2 is sometimes used for simple structural shapes and electrical insulation.

Properties

Fabrication

FR-2 can be machined by drilling, sawing, milling and hot punching. Cold punching and shearing are not recommended, as they leave a ragged edge and tend to cause cracking. Tools made of high-speed steel can be used, although

tungsten carbide Tungsten carbide (chemical formula: WC) is a chemical compound (specifically, a carbide) containing equal parts of tungsten and carbon atoms. In its most basic form, tungsten carbide is a fine gray powder, but it can be pressed and formed into ...

tooling is preferred for high volume production. Adequate ventilation or respiration protection are mandatory during high-speed machining, as it gives off toxic vapors.

Trade names and synonyms

* Carta * Haefelyt * Lamitex * Paxolin, Paxoline * Pertinax, taken over by Lamitec and Dr. Dietrich Müller GmbH in 2014 * Getinax (in the Ex-USSR) *

Phenolic paper Phenolic paper is a material often used to make printed circuit board substrates (the flat board to which the components and traces are attached). It is a very tough board made of wood fibre and phenolic polymers. It is most commonly brown in co ...

* Preßzell * Repelit * Synthetic resin bonded paper (SRBP) * Turbonit * Veroboard * Wahnerit

Applications

Properties

Fabrication

Trade names and synonyms

See also

References

Further reading