FR1-FR4

FR1 is basically the same as FR2. FR1 has a higher TG of 130^oC instead of 105^oC for FR2. Some laminate manufacturers who produce FR1 may not produce FR2 since the cost and usage are similar and it is not cost effective for having both.

FR3 is also basically FR2. But instead of phenolic resin it uses an epoxy resin binder.

FR4 (FR = Flame Retardent)is a glass fiber epoxy laminate. It is the most commonly used PCB material. 1.60 mm (0.062inch). FR4 uses 8 layers glass fiber material. The maximum ambient temperature is between 120^o and 130^oC, depending on thickness.

In China FR4 is the most widely used PCB base material, next is FR1 then FR2. But FR1 and FR2 are usually used for 1-layer PCBs because they are not good for passing through holes. FR3 is not recommended to bu ilding multi-layer PCBs. FR4 is the best selection. FR4 is widely used because it is good to make from one- layer to multi-layer PCBs. With only FR4, PCB companies can make all kinds of PCBs, which leaves the management and quality control much easier, and eventually it can reduce the cost!

CEM-1 and CEM -3

CEM-1 Composite material composed of woven glass fabric surfaces and paper core combined with epoxy resin. Primarily used in the printed circuit board industry. Easy punching and excellent electrical properties and higher flexural strength than paper based grades. CEM-1 provides excellent mechanical and electrical properties, and punches well up to .093″.

CEM-3  is very similar to FR4. Instead of woven glass fabric a ‘flies’ type is used. CEM-3 has a milky white color and is very smooth. It is a complete replacement for FR4 and has a very large market share in Asia. It is a kind of flame retardant epoxy copper-clad plate glass material, is generally used in electronics with double sided and multilayer pcb boards. And CEM – 3 is a new printed circuit substrate material developed based on FR – 4. In recent years, CEM-3 is used to replace FR-4 in Japan, even more than the FR – 4 dosage.

Aluminum Metal Core

As Aluminum Metal Core PCB means the base material for PCB is metal, but not normal FR4/CEM1-3, etc, and currently what the metal used are Aluminum, Copper alloy. Aluminum Metal Core PCB are used instead of traditional FR4 or CEM3 PCBs because of the ability to efficiently dissipate heat away from the components. This is achieved by using a Thermally Conductive Dielectric Layer.

Flex and Rigid-flex

Flex and Rigid-flex circuit boards have become increasing popular due to their unique applications. Flex and Rigid-flex circuit boards can do what regular standard rigid circuit boards can not do. They can fold, twist, and wrap around tight/small packaging area.

Most flex circuit boards are being manufactured using “Kapton”, a material developed by Dupont Corporation. This polyimide film based material is resistant to heat, has dimensional stability and a low dielectric constant of 3.6. There are three variants of the Kapton material:

1. Pyralux LF (Acrylic Base Adhesive-not Flame Retardant)

2. Pyralux FR (Acrylic Base Adhesive-Flame Retardant)

3. Pyralux AP (Adhesiveless-for more Demanding high-performance applications)

PCBs By Material

Heavy Copper PCB

FR4 glass fiber PCB

Aluminum Metal Core PCB

CEM 1 CEM2 CEM3 PCB

FR1 FR2 FR3 PCB

Flex/ Rigid-Flex PCB

Rigid PCB

Rogers PCB/ Isola PCB

High TG PCB