Requirements and precautions for silicone potting of switching power supplies
Time:2024-07-29
Views:217
As a device composed of electronic components, switching power supplies must consider many aspects during the use and installation process. Similarly, the same is true for silicone potting of switching power supplies. So what are the requirements for glue filling of switching power supplies? In response to this issue, the editor will introduce it in detail.
Requirements for silicone potting of switching power supplies
1. Waterproofness. The silicone potting tightly wraps the entire electrical part of the product and completely isolates it from the outside world; no water, water vapor, acid, alkali, or salt can reach the circuit components, which can improve the waterproof, moisture-proof, and corrosion-resistant capabilities. Therefore, the glue you choose must have good fluidity. If the fluidity is not good, how can it penetrate deeply and completely seal? In addition, the bonding force must also be available, otherwise it will be useless if it is separated from the components after long-term alternation of hot and cold after potting, and the product life performance will also be affected.
2. Thermal conductivity. The power supply is a power product, which is to converts, controls, and outputs energy to the outside. To conduct the heat of the device as quickly and as much as possible, the glue is required to have good thermal conductivity.
The life of the electrolytic capacitor in the power supply is reduced by about half for every ten-degree increase in temperature, but you cannot add a heat sink to it; when the temperature of the transformer and inductor is high, many parameters are changing, and the whole design becomes more difficult, so you can‘t add a heat sink to it. The waterproof power supply needs to be sealed as a whole, and the thermal conductivity of air is very low, mainly relying on convection and radiation. But convection is impossible, and the components are all stuffy in the box. Therefore, filling with glue with good thermal conductivity can be equivalent to placing each component outside to dissipate heat, which not only increases the life but also simplifies the design.
2. Insulation strength, this is easy to deal with. Basically all glues are not conductive, but it should be noted that the curing reaction of epoxy AB glue is not complete and may be slightly conductive locally. There is also sand mixed in it for saving, which is hard to say. First, whether your sand has been processed by dehydration and other processes, or whether your sand will have some other elements that interfere with curing; whether the AB agent ratio is reasonable, whether the mixture is fully uniform, and whether other conditions are met.
4. Environmental protection requirements, generally have been certified. It depends on whether the provided products are consistent with the certified ones. There is still a lot of price difference between environmentally friendly and non-environmentally friendly materials.
5.There are many other parameters, you have to test them yourself. The main thing is that your supplier should be constant, his supply should be stable, and the process should be stable. Otherwise, the discreteness is too large.
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