Analysis of the appearance of metal film capacitance

When using metal film capacitors, I believe you will encounter a lot of problems, such as color changes, printing words are not clear, poor performance and so on.A product will inevitably arise problems, it is important to deal with the attitude of the problem and the speed of processing, timely detection of problems, analysis of the cause of the problem, and improve, is to serve customers.

1) Appearance color change Metal film capacitors are encapsulated by epoxy resin, epoxy resin encapsulation material a component of its color from iron red, iron yellow, red Dan according to a certain proportion of the adjustment, sometimes in the epoxy resin encapsulation after curing the phenomenon of color becomes darker, mainly because the pigment has changed. Iron oxide red is relatively stable, not easy to change. Red Dan heat up to 500 ℃ decomposition into a lead oxide and oxygen, but the oven will not reach such a high temperature, can be ruled out. And the iron oxide yellow is crystalline iron oxide hydrate, it is easy to get out of crystalline water when heating discoloration. Metal film capacitor in the oven heating curing process, close to the electric wire part of the possibility of excessive temperature, electric wire can be directly to the capacitor heating, the temperature is quite high, so it is easy to cause the decomposition of iron oxide yellow pigment, so that the capacitor color.After discovering the situation, we raised the distance between the capacitor and the base plate, and did not make the local temperature too high, solve the problem.

2) Printing Word does not dry The metal film capacitor uses the diluent to cooperate the encapsulation material production, has appeared the problem which the ink does not dry, in addition to the ink quality question, probably is the factory in the preparation diluent the process to add the defoaming agent. Defoamers are volatile, high-boiling organic compounds that reduce the surface tension of liquids and prevent the formation of bubbles or the reduction or elimination of the original foam. At the same time, they can also play a role in the polymer plasticized, it is evenly mixed in the polymer, to weaken the interaction between the polymer molecules, thereby reducing the viscosity, increase the fluidity and so on. When the metal film capacitor in the heating curing, it is easy to precipitate to the surface of the capacitor, so that the marking of ink and product adhesion. As a result, we have reduced the use of defoamers and solved this problem.