Wiring Harness News Jul-Aug 2022 - Page 14


Sealing Electronics With Vacuum Impregnation

Continued from page 1 _____________
be visible , but they are disastrous . Moisture or corrosive agents can seep into the leak path , causing a part to be ineffective , leading to a field failure .
The automotive industry needs vacuum impregnation because specifications often demand that components like fuel pumps , wiring harnesses , or encapsulated coils meet leak requirements to protect them from road salt and moisture , leaks from the transmission or brake fluid , or gasoline .
Most electronic parts must also be protected from heat , whether from an engine manifold or the hot temperatures inside today ’ s high-powered Pentium computers . Heat can cause plastic and metal to fluctuate at different temperatures , loosening the joint and reducing effectiveness .
If one seals a part with a rubber O-ring , it will become brittle and then crack over time . Likewise , if one puts a dollop of silicone around the connectors on the surface , that silicone is exposed to the elements , resulting in expansion , contraction , and thermal breakdown . Even a topcoat has the potential to crack , which opens a path for elements to get in . All these methods can leave excess residue on external surfaces , altering the part ’ s dimensions and impairing conductivity .
What Electronic Parts Can Be Sealed ?
The vacuum impregnation process can be used for sealing all types of electronic components . Traditionally , it ’ s mainly been used for things you might find under the hood of a vehicle , such as a connector , wire assemblies , and wire harnesses . But the drive toward zero fault tolerance has prompted the sealing of parts used in electronic equipment , even in commercial equipment . This includes computer cables , windings for electric motors , and portable wireless applications , where mechanical shock can cause connection failures . The Benefits of Vacuum Impregnation
With electronics , there are three main reasons why vacuum impregnation is used .
1 . Seal Leak Paths : Vacuum impregnation prevents fluids from leaking by sealing the leak paths .
_____________ Continued on page 16