What is FR-4 Epoxy Fiberglass Sheet? 

A. FR-4 Epoxy Fiberglass Sheet :

FR-4 (or FR4) is a grade designation assigned to glass-reinforced epoxy laminate sheets, tubes, rods and printed circuit boards (PCB). FR4 is a composite material composed of woven fiberglass cloth with an epoxy resin binder that is flame resistant (self-extinguishing).

"FR" stands for flame retardant, and denotes that safety of flammability of FR4 is in compliance with the standard UL94V-0. FR-4 is created from the constituent materials (epoxy resin, woven glass fabric reinforcement, brominated flame retardant, etc.) by NEMA in 1968.

FR-4 Epoxy Fiberglass Sheet is a popular and versatile high-pressure thermoset plastic laminate grade with good strength to weight ratios. With near zero water absorption, FR-4is most commonly used as an electrical insulator possessing considerable mechanical strength. The material is known to retain its high mechanical values and electrical insulating qualities in both dry and humid conditions. These attributes, along with good fabrication characteristics, lend utility to this grade for a wide variety of electrical and mechanical applications.

B.FR-4 Epoxy Fiberglass Sheet features:

Good mechanical workability.

Good heat resistance and moisture resistance.  

In high temperature electric performance is stable.

Higher mechanical properties and dielectric properties.  

In the middle temperature with high mechanical properties.

C.FR-4 Epoxy Fiberglass Sheet applications:

Used in mechanical, electrical and electronic high insulation structure parts.  

Used in high-performance electrical insulation requirements.

Chemical machine parts.

General machines parts and gear, generators, Pads, base, baffle.

Generator, transformer, fixture, inverter, motor

Electric insulation component.