Factors affecting the electrical strength of nema fr4 board

Nema fr4 board is widely used in many fields, but it does not mean that the performance of the Nema fr4 board is very good, and there will be no problem when it is used. For example, when in use, the electrical strength of fr4 glass epoxy is affected to a certain extent, resulting in the effect is not very obvious. In order to reduce the occurrence of this phenomenon, let's understand the factors that affect the electrical strength of fr4 fiberglass, so as to pay more attention to it in future use.

(1) Sample thickness: When the fr4 fiberglass sheet is very thin, the breakdown voltage is proportional to the thickness, that is, the electrical strength has nothing to do with the thickness. When the thickness of the fr4 fiberglass sheet increases, it will make it difficult to heat dissipation, and impurities, bubbles and other factors will reduce the electrical strength.

(2) Temperature: The electrical strength of fr4 glass epoxy decreases with the rise of temperature above room temperature.

(3) Humidity: If moisture enters the fr4 glass epoxy, electrical strength will be reduced.

(4) Voltage action time: For most insulation boards like nema fr4 sheet, electrical strength decreases with the extension of voltage action time. In the test, the voltage boost speed is fast, the electrical strength is high, and the voltage action time of the step boost or slow boost is long, which can better reflect the existence of defects such as thermal effect and the air gap in the material. Therefore, in the general test method, it is stipulated that the shock type pressure boost method is not adopted, and the method of continuous pressure boost or step-by-step pressure boost is adopted.

(5) Mechanical stress or mechanical damage: The electrical strength will be reduced after the fr4 glass epoxy sheet is subjected to mechanical stress or mechanical damage. Laminated product sample processing should be as far as possible to avoid strong damage.

(6) Sample: Sample can not be polluted, thin nema fr4 insulation board sample can not be wrinkled. This will reduce the breakdown voltage.

(7) There is water or carbon in the transformer oil: If the breakdown of the fr4 fiberglass sample is to be tested in transformer oil, the transformer oil should meet the standard requirements. For a long time, the transformer oil will absorb moisture and have many breakdown residual charcoal, which will make the sample breakdown voltage reduced. Transformer oil should be timely handled or replaced.

Through the above factors affecting the electrical strength of the fr4 fiberglass, I believe that everyone has a certain understanding. This requires us to pay more attention in the daily operation, so as to ensure that the electrical strength of the nema fr4 board will not be affected.