Designing for Selective Robotic Conformal Coating Processing: Rule 9 “A flat board is a happy conformal coating process”
Many printed circuit boards can become warped in the manufacturing process. Or, they can bend in the conformal coating process if not adequately supported. This means that the surface is not even for the valves to travel across. For processes where the valves are running very close to the surface of the board this can be critical and lead to defects.
The board should be flat and sufficiently rigid to prevent sagging during dispensing or curing, otherwise coatings may flow and pool in unexpected fashions. In particular, heavy boards may need to be palletized to provide sufficient rigidity.
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.