To help electronics manufacturers prevent voids when potting and encapsulating, adhesives specialist Intertronics has produced a white paper. It covers just about every aspect of managing voids including causes, storage, air removal methods, application methods, contamination and shrinkage
Intertronics says that trapped air, or voids (which may not actually contain air), can cause failure in electronics assemblies whether they be micro-encapsulated wire bonds or large potted power supplies. Voids can subvert the very purpose of the encapsulating polymer, by compromising thermal conductivity or electrical insulation. Voids and delamination can also provide pathways for moisture or other contaminants, which can lead to short circuits or chemical damage. Further, bubbles in the polymer weaken its physical structure, allowing greater susceptibility to damage or cracking from physical or thermal shock.
“Formulators of multi-component adhesives, potting and encapsulation materials are careful not to supply products with entrapped air,” said Paul Whitehead, Strategic Accounts Manager at Intertronics. “Entrapped air in a mixed material is usually a processing issue. Voids can be caused by incorrect storage of materials, hand mixing of resin and hardener, not degassing a compound correctly, improper application, air saturation from pressurised feed systems, reaction with contaminants or shrinkage of the compound during cure.”
To help manufacturers identify and address these causes, the Intertronics white paper discusses each step in detail, explaining what manufacturers can do to mitigate the risk. For example, if a process friendly viscosity can be specified, it can simplify potting and encapsulating processes and allow easier mixing, self-levelling and self-degassing. It also discusses the benefits of different mixing equipment, such as planetary centrifugal mixers and the 2-K-DOS Metering, Mixing and Dispensing System.
Intertronics supplies a range of potting and encapsulating materials and supported mixing and dispensing equipment to electronics manufacturers across the UK. The company says that it recognises that every adhesives process is different and that it works with individual customers to come up with the most appropriate solution for a given application. One can download the white paper here.