>To Coat or not to Coat that is the Question?Thursday, 23rd August 2012 posted by Kim Munro
When a pcb assembly fails in the field it can have dire consequences. There can of course be a number of root causes for the failure. However if your products are regularly exposed to heat and moisture in particular, it may be worth considering having your assemblies conformally coated to prevent accelerated aging. The coatings themselves differ for various field applications but they all are designed to prevent damage to the pcb assembly from heat, moisture, dust, dendritic growth and some solvents.
Traditionally conformal coatings were applied by using either a dip process (masking off components that did not need to be coated) or by a hand brushing method making the process labour intensive, messy and inconsistent. However in recent years systems have been developed to apply a controlled, consistent amount of coating by the use of robotic spray methods. Kingfield invested in one such system in 2012.
Darren Dooley, Process Engineering Manager commented, “The acquisition of the robotic spray coating system which is operated in line with an IR oven has given us significantly increased coating capacity. We are now routinely coating in excess of 5,000 complex assemblies each month with a much greater degree of consistency and control over the resulting coating thickness and accuracy.
We have the ability to selectively coat, pot and apply coating beads to assemblies of all shapes, sizes and thicknesses to an accuracy of 25 microns thus enabling us to differentiate those parts on the assembly that need to be coated from those that don’t without the need for masking, previously a very time consuming activity. Customers have been very impressed with the repeatability of the process and the productivity improvements we have achieved thus making conformal coating a ‘must have’ rather than a ‘nice to have’ process”.