Designing for Selective Robotic Conformal Coating Processing: Rule 12 “Coating 3D components is hard work. Why do it?”
When a circuit board surface looks like a scene from a cityscape and is highly 3D in nature, choosing to coat the sides of components is a really difficult process. You will need at least 5 axes of rotation, the process will slow down, quality really goes down and it looks awful cosmetically. If you don’t need it, don’t do it.
Make coating component packages optional. Coating the sides of a 3D device is difficult, especially since the coating is subject to gravity, as well as de-wetting due to mould release agents used in the component fabrication. The plastic or metal package mouldings are almost certainly more resistant to humidity or other forms of water than any conformal coating.
The Rules for Selective Conformal Coating are straightforward. Follow them and you can save money and time in your application process. However, if the Rules are not followed, the resultant circuit board design can challenge even the most sophisticated conformal coating system and its operator to achieve the finish desired.
Click Designing Circuit Boards for Selective Robotic Conformal Coating for further Rules.