Meaning
Processing methods that apply a low-pressure environment to a liquid material prior to curing remove trapped air bubbles that could compromise the physical or electrical properties of the finished part. Performing vacuum degassing on potting compounds before they are dispensed onto a printed circuit board ensures a dense, bubble-free insulation layer that has high dielectric strength. This process is executed in a sealed chamber connected to a high-capacity vacuum pump.
Bubble Elimination
Air bubbles trapped in a cured resin can act as thermal barriers or lead to electrical breakdown under high voltage. Subjecting the liquid mixture to a vacuum causes these bubbles to expand and rise to the surface, where they burst.
Viscosity Interaction
The effectiveness of the process is influenced by the viscosity of the compound, with highly viscous materials requiring longer cycle times or higher vacuum levels. Heating the mixture slightly can reduce the viscosity, which speeds up the removal of the trapped gases.
Dispensing Quality
The use of degassed materials is critical for ensuring consistent volume dispensing in automated assembly lines. Any remaining air pockets can cause the dispensing system to deliver an incorrect amount of material, which can result in incomplete coverage of the electronic components. This variation can lead to hotspots or areas that are vulnerable to moisture ingress.
Implementing this preparation step ensures the uniformity and long-term reliability of the potted assemblies.
