Designing for Selective Robotic Conformal Coating Processing: Rule 2
Conformal Coating materials are liquids that flow in unpredictable ways on a circuit board due to surface tension affects. These problems with flow can create defects like capillary (scavenging) and unwanted flow into connectors. Therefore, consider the following rule.
Maintain a minimum 2.5mm distance between MUST coat areas and MUST NOT coat areas. If you do, be prepared for production people to attack you with a pitch fork as it may not be possible to prevent the liquid flowing into restricted areas.
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.