PCB Tech - Knowledge and standards for printed circuit boards

PCB board knowledge and standards:

At present, there are several types of copper clad laminates widely used in China, and their characteristics are as follows: the types of copper clad laminates, the knowledge of copper clad laminates, and the classification methods of copper clad laminates.

Generally speaking, according to the different reinforcing materials of the board, it can be divided into: paper base, glass fiber cloth base, composite base (CEM series), multilayer multilayer board and special material base (ceramic, metal core base (common aluminum substrate), etc. ) Five categories.

If classified according to the different resin adhesives used in the board, the common paper-based CCI. There are: phenolic resin (XPc, XxxPC, FR-1, FR-2, etc.), epoxy resin (FE-3), polyester resin and other types. Common glass fiber cloth base CCL has epoxy resin (FR-4, FR-5), which is currently the most widely used type of glass fiber cloth base. In addition, there are other special resins (with glass fiber cloth, polyamide fiber, non-woven fabric, etc. as additional materials): bismaleimide modified triazine resin (BT), polyimide resin (PI), Diphenylene ether resin (PPO), maleic anhydride imine-styrene resin (MS), polycyanate resin, polyolefin resin, etc.

At present, the main standards of substrate materials are as follows:

1. National standards: China's national standards for substrate materials include GB/T4721-47221992 and GB4723-4725-1992. The copper clad laminate standard in Taiwan, China is the CNS standard, which is based on the Japanese JIs standard and was formulated in 1983 release.

2. International standards: Japanese JIS standards, American ASTM, NEMA, MIL, IPc, ANSI, UL standards, British Bs standards, German DIN and VDE standards, French NFC and UTE standards, Canadian CSA standards, and Australian standards AS standards, FOCT standards of the former Soviet Union, international IEC standards, etc.; suppliers of PCB design materials, common and commonly used are: Shengyi \ Kingboard \ International, etc.

PCB circuit board board introduction: according to the brand quality level from bottom to high as follows: 94HB-94VO-CEM-1-CEM-3-FR-4

The detailed parameters and uses are as follows:

94HB: ordinary cardboard, not fireproof (the lowest grade material, die punching, cannot be used as power supply board) 94V0: flame retardant cardboard (die punching) 22F: single-sided half glass fiber board (die punching) CEM-1: single Face glass fiber board (must be drilled by computer, not die punching) CEM-3: double-sided half glass fiber board (except for double-sided cardboard, it is the lowest end material of double-sided board, simple double-sided board can use this material, which is better than FR -4 will be cheaper 5~10 yuan/square meter) FR-4: double-sided fiberglass board

1. The classification of flame retardant properties can be divided into four types: 94VO-V-1 -V-2 -94HB

2. Semi-cured film: 1080=0.0712mm, 2116=0.1143mm, 7628=0.1778mm

3. FR4 and CEM-3 are all plates, fr4 is glass fiber board, cem3 is composite substrate

4. Halogen-free refers to the base material that does not contain halogen (fluorine, bromine, iodine and other elements), because bromine will produce toxic gas when burned, which is environmentally friendly.

5. Tg is the glass transition temperature, that is, the melting point.

6. The circuit board must be flame-resistant. It cannot burn at a certain temperature and can only be softened. The temperature point at this time is called the glass transition temperature (Tg point), and this value is related to the dimensional durability of the PCB board.

The PCB factory should have the ability to provide customers with fast and expedited precision PCB samples, as well as mature circuit board production and manufacturing technology.