Important FR4 Material Properties
FR4 is a common epoxy fiberglass reinforced laminate, particularly noted for its strength, electrical insulation, и устойчивост на топлина. These fundamental specifications classify it as an excellent electrical insulator, PCB, and aerospace bracket, among other critical precision components. The following are the distinguishing qualities of FR4:
1. Висока диелектрична якост
FR4 has very high electrical insulation, but it is usually preferred in high-voltage applications, with dielectric strength values being very high (more than 19.7 kV/mm). This is essential in printed circuit boards (PCBS), конектори, and switchgear, where signal isolation is a necessity.
2. Топлинна устойчивост
FR4 can be used at 130-150 o C continuous service temperatures with both mechanical and electrical stability. This qualifies it to be used in soldering works and places exposed to intense heat. It has a low heat deflection temperature, which enables it to be used in the manufacturing of industrial and electronics equipment.
3. Стабилност на размерите
FR4 has a low thermal coefficient of expansion (~14 16 ppm/C), and is not subject to warp or distortion due to mechanical or thermal loads. It possesses strict tolerances, hence it is suitable to apply in complex geometries or the assembly of mating assemblies.
4. Механична якост
FR4 has a high compressive modulus with a flexural strength of more than 480 MPa, which makes it very rigid and able to support high loads. It finds its usual application in structural support jobs such as aerospace brackets in space and automotive systems, as well as spacers and backplanes.
5. Устойчивост на влага
FR4 absorbs few amount of water (обикновено <0.1%) and is quite stable under wet or humid conditions. This water resistance serves to safeguard delicate circuits and provides long-term electrical stability.
6. Flame Retardancy
Както подсказва името, Fr (Пламък забавител) 4 has a UL94 V-0 flammability rating, which means that it can self-extinguish in a short course of time without dropping. This feature guarantees safety in places of confined spaces or thermally hot locations such as power panels and transformers.
7. Химическа устойчивост
FR4 FR4 is resistant to acids, бази, и разтворители, so it is used in chemically exposed applications such as labs, battery systems, or industrial control units. It does not diminish to an easily broken condition at all, so long as it is used.
8. Обработваемост
FR4 machines well with proper tooling, although it is abrasive because of the glass fibers. It serves a wide range of post-processing finishes, тесни допустими отклонения, и сложни форми, which makes it helpful in manufacturing custom parts in several industries.
Можем да обобщим тези свойства в следващата таблица：
Имот | Typical Value / Описание | Полза |
Диелектрична якост | > 19.7 kV/mm | Ideal for high-voltage insulation |
Топлинна устойчивост | Up to 130–150°C continuous | Stable in high-temperature environments |
Стабилност на размерите | CTE ≈ 14–16 ppm/°C | Maintains precision under thermal/mechanical stress |
Flexural Strength | > 480 MPa | Provides excellent rigidity and structural integrity |
Поглъщане на вода | < 0.1% | Performs well in humid or wet environments |
Flame Retardancy | UL94 V.-0 rated | Safe for electrical and enclosed systems |
Химическа устойчивост | Resists acids, бази, и разтворители | Suitable for chemically harsh environments |
Обработваемост | Abrasive but CNC-compatible | Allows precise fabrication of complex parts |
