PCB Material Classification and Selection
When designing a PCB to factory fabrication, how to choose PCB material?
PCB material classification:
1. According to different materials (the most commonly used classification method)
Paper substrate (FR-1, FR-2, FR-3)
Epoxy glass cloth substrate (FR-4, FR-5)
Composite Substrates (CEM-1, CEM-3)
HDI sheet (RCC)
Special substrates (metal substrates, ceramic substrates, thermoplastic substrates, etc.)
2. Divided by resin
Phenolphthalein resin board
Epoxy board
Polyester resin board
BT resin board
PI resin board
3. According to the flame retardant performance
Flame retardant type (UL94-VO, UL94-V1)
Non-flame retardant type (UL94-HB grade)
The principle of PCB material use:
- For general electronic products, use FR4 epoxy glass fiber substrate
- For the use of high ambient temperature or flexible circuit boards, polyimide glass fiber substrates are used.
- For high-frequency circuits, you need to use PTFE glass fiber substrate;
- For electronic products with high heat dissipation requirements, metal substrates should be used.
Factors to consider when selecting PCB materials:
- Substrate with higher glass transition temperature (Tg) should be properly selected, Tg should be higher than the operating temperature of the circuit
- Low coefficient of thermal expansion (CTE) is required. Because the thermal expansion coefficients of X, Y, and thickness directions are inconsistent, the PCB may be easily deformed, and in severe cases, the metalized holes may be broken and the components may be damaged.
- High heat when required. General requirements PCB can have 250 °C / 50S heat resistance.
- Good flatness is required. SMT PcB warpage requirements <00075mm/mm.
- In terms of electrical properties, high-frequency circuits require materials with high dielectric constant and low dielectric loss. Insulation resistance, voltage strength, arc resistance must meet product requirements.
What are the normal of PCB materials?
King Sun standing FR-4 sheet specifications:
| Material Type | Base Laminate Thickness (+/-) |
| 1 | 0.2+/-0.038mm (Copper H/H,1/1oz) |
| 2 | 0.25+/-0.038mm (Copper H/H,1/1oz) |
| 3 | 0.36+/-0.05mm (Copper H/H,1/1oz) |
| 4 | 0.41+/-0.05mm (Copper H/H,1/1oz) |
| 5 | 0.51+/-0.064mm (Copper H/H,1/1oz) |
| 6 | 0.61+/-0.064mm (Copper H/H,1/1oz) |
| 7 | 0.71+/-0.064mm (Copper H/H,1/1oz) |
| 8 | 0.8+/-0.1mm (Copper H/H,1/1oz) |
| 9 | 0.9+/-0.1mm (Copper H/H,1/1oz) |
| 10 | 1.0+/-0.1mm (Copper H/H,1/1oz) |
| 11 | 1.2+/-0.13mm (Copper H/H,1/1oz) |
| 12 | 1.5+/-0.13mm (Copper H/H,1/1oz) |
Remark:
1) The thickness of the sheet is 0.8mm or less and the thickness of the base copper is not more than 0.8mm.
2) The above sheet thickness tolerance is IPC-4101 CLASS B/L. If the design requires the use of tighter tolerance grade sheets, a “Special Material Order Notice” must be issued to the relevant department for purchase.
3) The above sheet suppliers commonly used by our company are KB (Jianyu), NANYA (South Asia), VENTEC (Tenghui) and SHENYI (shengyi), among which the six specifications of NANYA are 36”x48” , 40”x48. ”, 42”x48”, 36.5”x48.5”, 40.5”x48.5” and 42.5”x48.5”, other suppliers’ specifications are 36”x48”, 40”x48”, 42”x48”,37 “x49″, 41″x49″ and 43″x49”.
4) The base copper thickness of our company is H/HOZ and 1/1OZ. If we exceed this range, we need to issue a “special order notice” to relevant departments.
5) FR-4 sheets with sheet thicknesses other than this range, eg 0.15 ± 0.025mm (without copper),0.1±0.018mm (without copper), 1.9±0.18mm (with copper), 2.3±0.18mm (with copper)
In the company can produce and can be purchased, but ME need to “special materials order book” to the relevant departments.