Potting of AC to DC power module is very important.This process involves not only the protection of AC-DC power modules(waterproof,moisture-proof,dust-proof,anti-corrosion,etc.),but also the thermal design of AC-DC power modules.
Power module potting materials are commonly divided into three categories:epoxy resin,polyurethane and silicone rubber.
Epoxy resin cannot be used for stress sensitive and module potting with patch components due to hardness,and is basically eliminated in the module power supply.However,due to the low cost,this epoxy resin is also applied to a micro-power supply with lower cost requirements.Some domestic poor power supply manufacturers also use this epoxy resin for AC-DC power supply modules,but due to stress problems,this power failure rate is very high,and buyers are suffering.
Polyurethane has been used in China for a period of time,but its hardness is high,it is not convenient to repair,coupled with the price reduction of silicone rubber,the cost performance of polyurethane is not high.Basically,the application is not seen in China.
Now the most used in the power module potting is to use potting silicone to potting.This kind of silica gel is generally 1:1 ratio,easy to operate.It should be designed to pay attention to the thermal conductivity of AC-DC power module when potting.However,the bonding ability is not too strong and can be improved by using a primer.