What is FR-4 PCB?
FR-4 PCB refers to the PCB processed with FR-4 copper clad laminate as the base material. FR-4 is both a name and a standard grade. The name indicates the basic quality of glass fiber reinforced epoxy laminates used in the manufacture of printed circuit boards. The “FR” in the name stands for flame retardant, while the 4 distinguishes the material from the rest of its class. The material of FR4 is a composite structure. The most basic layer of the material is fiberglass woven into a thin cloth-like sheet. Fiberglass gives FR4 the necessary structural stability. This innermost fiberglass layer is then surrounded and bonded by a flame retardant epoxy. This resin gives the material rigidity along with other physical properties.
FR4 is a standard for glass fiber reinforced epoxy compounds defined by NEMA (National Electrical Manufacturers Association). FR stands for “flame retardant” in English and indicates that the material meets the UL 94V-0 standard for flammability of plastic materials. For safety reasons, FR-4 PCBs should all meet the 94V-0 standard. Because when the PCB is short-circuited or overheated and catches fire, it ensures that the fire does not spread and is quickly extinguished. But at present, some PCB manufacturers in the market use non-flame retardant FR-4 production in order to save their cost, which has a great potential safety hazard. JHDPCB promises that all the FR-4 PCBs we produce are made of well-known brands of CCL that meet the 94V-0 standard, to know which materials we can use, please refer to TYPES AND DATABASES OF COPPER CLAD LAMINATE(CCL).
Another important parameter of FR-4 is the TG value, which refers to the glass transition temperature (TG). Typically between 115°C and 190°C, depending on the manufacturing method and resin used. The FR4 PCB produced by JHDPCB has a TG value of up to 280°C. More detailed TG value introduction for PCB production. See HIGH TG PCB.
FR-4 usually uses bromine, a chemical element called halogen that is fire resistant. It replaces G-10, another compound with lower resistance in most applications. JHDPCB can produce lead-free or halogen-free PCBs to meet some boards with environmental protection requirements.
FR4 has a good strength-to-weight ratio. It does not absorb water and maintains a high and good insulating ability in dry or wet environments. In addition, FR-4 has good machining performance, it is easy to do shape processing and can maintain certain rigidity, and the price is relatively low, which is one of the best choices for PCB production.
