Plasma activation prior to potting ensures a good hermetic seal, reduces current leakage and provides stronger physical bonding to the device. The protection of electronic or electrical devices by an encapsulating resin is referred to as “potting”. Potting provides electrical insulation and protection from moisture, high/low temperatures, and physical and electrical stress. It can also function as a flame retardant, shock absorber and heat sink. Poor “wetting” of the potting material to the device is common, particularly to low surface energy polymers. This can result in poor bonding and voiding. Plasma activation raises surface energies and ensures good wettability, and more complete flow of resins onto almost all low energy polymer materials, including PTFE, silicone rubber and Kapton®.
In one case study, a major manufacturer of discrete electrical components produced several million potted electrical parts per month. Their defect rate due to ‘leakers’ was as high as 5%. PVA TePla was reduced their defect rate to 0.5% using plasma treatment to improve the bond between the potted compound and the Veloxâ housing. Due to the large volume and small sizes of the components, PVA TePla America developed a rotary basket plasma reactor for this application. The system has been operating reliably for several years with minimal down time.
