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The basic raw materials for PCB's, are actually dielectric substrates that have been clad with copper foil and are available in a
variety of materials and thicknesses. Selecting the right material depends on the electrical, thermal and mechanical operation that
the application demands. The ambient temperature is in most cases a very important factor. In the table below the demands per
industry are shown. The most commonly known material FR4, a substrate based on a glass/epoxy composite, will be suitable for most
applications.
| Worst Case Environments |
| Cat. |
USE | Min Temp |
Max Temp | Service |
| 1 | Consumer | 0°C | +60°C | 1-3 Yrs |
| 2 | Computer | -15°C | +60°C | ~5 Yrs |
| 3 | Telecomm | -40°C | +85°C | 7-20 Yrs |
| 4 | Civ Aircraft | -55°C | +95°C | ~10 Yrs |
| 5 | Industrial | -55°C | +55°C | ~10 Yrs |
| Auto Pass Cmp | -55°C | +55°C | ~10 Yrs |
| 6 | Mil Gnd/Ship | -55°C | +95°C | ~5 Yrs |
| 7 | Space | -40°C | +85°C | 5-20 Yrs |
| 8 | Mil Aircraft | -55°C | +95°C | ~5 Yrs |
| 9 | Auto Engine | -55°C | +125°C | ~5 Yrs |
Some more detailed information on raw materials:
FR4 (FR = Flame Retardent)is a glass fiber epoxy laminate. It is the most commonly used PCB material. 1.60 mm. FR4 uses 8 layers
og glassfiber material. The maximum ambient temperature is between 120° and 130°C, depending on thickness.
Same as FR4, but the maximum ambient temperatures are between 140° and 170°C.
FR2 is a paper materials with a phenolic binder. It is UL 94-V0.
FR1 is basically the same as FR2. FR1 has a higher TG of 130°C instead of 105°C for FR2. Some laminate manufacturers which produce
FR1 will not produce FR2, since cost and usage are similar and there is no advantage for having both.
FR3 is also basically Fr2, but instead of phenolic resin it uses an epoxy resin binder. The basic layer is paper. It is not
suitable for Plated Through Hole.
CEM-3 (CEM = Composite Epoxy Material) 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 Japan.
CEM-1 is a paper based laminate with one layer of woven glass fabric. It is not suitable for Plated Through Hole.
G10 is out of fashion now for standard PCB's. it is woven glass fabric with a different epoxy from FR4.
It is only UL 94-HB. The main usage nowadays is for thin watch circuit, since it's very punchable.
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