FR-2 (Flame Resistant 2) is a
NEMA 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 distribu ...
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 and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a laminated sandwich str ...
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 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 f ...
, 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 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
* Preßzell
* Repelit
* Synthetic resin bonded paper (SRBP)
* Turbonit
*
Veroboard
* Wahnerit
See also
*
Formica (plastic)
Formica Laminate is a laminated composite material invented at the Westinghouse Electric Corporation in the United States in 1912. Originally used to replace mica in electrical applications, it has since been manufactured for multiple applica ...
*
Micarta
References
Further reading
*
Composite materials
Printed circuit board manufacturing
Synthetic paper
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