Removal Methods of Conformal Coatings

Removing Conformal Coatings


Conformal coating must be removed if damaged PCB components need to be replaced, or if there are coating defects to be removed. It is critical to choose the most appropriate method for each type of coating to ensure that the PCB components are not damaged during the removal process.

There are 5 basic methods of removing conformal coating:

Chemical Solvents
They are highly effective at removing liquid-based conformal coatings – acrylic, silicone, and urethane. Acrylic coating is easy to remove due to its low chemical resistance, whereas silicone and urethane coatings require specialised solvents, a longer soak period and brush agitation for complete removal. For precise spot removal, check out our conformal coating remover pen here.
Peeling
Conformal coating is removed by cutting and peeling with a dull knife or blade which is commonly used in thick silicone coatings. It is less reliable than other methods as it can harm the components if precision control is not taken.
Thermal
Conformal coating is gently heated with a thermal parting device until it melts, and the temperature must be kept low to avoid damaging the components. As the fumes emitted can be extremely harmful, proper ventilation is needed. This method works well with most conformal coatings.
Micro-Blasting
Epoxy and parylene coatings are difficult to remove due to their natural durability, hence a micro blaster is often used. It involves using a concentrated mix of fine abrasive powder and compressed air to abrade the coating.
Grinding and Scraping
Conformal coating is removed by abrading the PCB with a sharp knife or a handheld grinder. It is more effective with harder conformal coatings like epoxy, parylene and polyurethane coatings, but it is only used as a last resort because of the severe damage it can cause.

 

Conformal coating removal can be costly and time consuming; thus, it is best to avoid it by preventing PCB components damage and conformal coating defects. In the next post, we will take a look at the common coating defects, its causes and how to prevent it. Stay tuned to find out!