Reason for pinholes in safety capacitors

The outer layer of the safety capacitor is made by encapsulating the epoxy resin and then sintering at 280 °C. The cause of bubbles and pores in the outer seal of the epoxy resin is: the first is the gas in the encapsulant, and the second is the gas inside the safety capacitor chip. Therefore, before the impregnation and encapsulation, the epoxy resin encapsulation material and the safety capacitor chip are vacuum processed.

Since there are many gases in the inside of the safety capacitor chip and the lead wire soldering, the vacuum processing is not good, and the gas expands during the heating and solidification process of the encapsulating material, so that the safety capacitor generates bubbles and pores. If the safety capacitor is vacuum-sealed, it is slowly solidified with the encapsulating material after being left at room temperature for a period of time. The encapsulating material reaches a certain hardness, and is placed in the baking box to be heated and solidified, and bubbles are not easily generated.