What is fr1,fr2,fr3,fr4,fr5 insulation board

June 14, 2023

What is fr1,fr2,fr3,fr4,fr5 ?

In fact, fr1,fr2,fr3,fr4,fr5 represents the grade, fr1 is the lowest, fr5 is the highest, but the market with more or fr4 this grade, because regardless of the current performance needs and prices are more appropriate. And although the emergence of fr5 grade, but relatively speaking the demand for the product is not so high.
FR4 sheet

FR4 basic characteristics

1.Vertical laminar bending strength A: Normal: E-1/150, 150 ± 5 ℃ ≥ 340Mpa

2.Parallel laminar impact strength (simple beam method): ≥ 230KJ / m

3.Insulation resistance after water immersion (D-24/23): ≥ 5.0×108Ω

4.Vertical layer to layer electrical strength (in 90 ± 2 ℃ transformer oil, plate thickness of 1mm): ≥ 14.2MV / m

5.Parallel layer breakdown voltage (in 90 ± 2 ℃ transformer oil): ≥ 40KV

6.Relative dielectric constant (50Hz): ≤5.5

7.Relative dielectric constant (1MHz): ≤5.5

8.Dielectric loss factor(50Hz):≤0.04

9.Dielectric loss factor(1MHz):≤0.04

10.Water absorption (D-24/23, plate thickness 1.6mm): ≤19mg

11.Density: 1.70-1.90g/cm³

12.Flammability: FV0

The biggest feature of fr4 is the flame retardant and anti-voltage strength is superior, so now many insulation gaskets, transformer room panels are used fr4 board.

FR4 FR5 plate