FR4 Materials In PCB Manufacturing

What is FR-4 laminate & FR-4 PCB?

FR4: FR4 is a standard defined by NEMA for glass reinforced epoxy laminates.

FR refer to “Flame Retardant” and means that the material with the UL94V-0 standard for the flammability of plastic materials. If the 94V-0 code available on all FR-4 PCBs. It ensures that the fire does not spread and goes out quickly when the material burns. And 4 distinguishes this material from other similar materials. FR4 material is a composite material structure. The most basic layer of the material is fiberglass, which is woven into a thin cloth surface.

FR-4 PCB: FR-4 print circuit board refers to the PCB processed with FR-4 copper base material. FR4 is the most common grade of dielectric material used to manufacture circuit boards. This material also common used in single-sided, double-sided, and multi-layer PCBs.

What are the fr4 material properties?

1. Flame Retardant:

Chemicals used in materials to prevent or delay the spread of fire are called flame retardants. FR4 substrate has excellent thermal, mechanical and electrical properties, making it an ideal choice for various electronic applications. Flame retardant laminates and prepregs are widely used in various manufacturing processes and produce predictable results.

2. Good Electrical Performance:

The electrical characteristics of PCB material are very important for signal integrity and impedance consideration. They specify the speed at which the electrical signal travels through the material and how much charge can be retained in a given volume. The following table lists some important electrical characteristics and their typical values.

3. Hygroscopicity Is Good:

Hygroscopicity is the ability of PCB materials to resist water absorption when immersed in water. It is given by the increased percentage in the weight of the circuit board substrate due to water absorption under controlled conditions. The moisture absorption of FR4 material is as low as 0.10% after putting it in water for 24 hours.

FR-4 Material Types and FR4 properties.

Standard FR4: As the name suggests, it is standard FR-4 with heat resistance of about 140℃to 150℃.

FR4 with high Tg: This type of FR-4 has a high glass transition temperature (TG) at 180℃.

FR4 with high CTI: The relative tracking index is above 600 volts.

FR4 without copper laminate: Suitable for insulating boards and board supports.

FR4 G10: A glass fiber and resin laminated composite material, which has the characteristics of insulation, corrosion resistance and wear resistance.

What Should Be Paid Attention To When Purchasing FR4 PCB?

Flame retardant. For safety reasons, FR-4 PCB shall comply with UV 94V-0 standard. Because when the PCB is short circuited or overheated and catches fire, the fire will go out immediately without causing fire.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

Another important parameter of FR-4 is the TG value. Which refers to the glass transition temperature (TG). The range is between 115°C and 190°C, the higher the TG, the higher the temperature that the FR-4 PCB can withstand. The FR4 PCB produced by JHDPCB has a fr4 material properties TG value of up to 280°C. More detailed TG value introduction for PCB production. 

FR-4 PCB thickness. Common fr4 pcb board thickness ranges from 0.6-3.0mm, such as fr4 0.8mm, fr4 1.0mm, fr4 1.6mm, fr4 2.0mm. The thickness of fr4 pcb board less than 0.6mm is called ultra-thin FR-4, and the thinner the fr4 pcb, the more difficult it is to produce.

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