At MicroCare, we often are asked about cleaning conformal coatings, and the SMTAi Expo in Chicago this week was no exception. Dan Sinclair, MicroCare National Sales Manager, was on a televised panel at the expo discussing the pros and cons of cleaning and conformal coatings.
These materials are very important for PCBs that are expected to operate in a harsh environment. Coatings keep water, dust, salt and dirt from touching delicate components and degrading the performance of the boards. For example, conformal coatings often are used on PCBs that might be near the ocean, outdoors, in aviation, in dusty cities and in dirty factories.
There are two issues associated with conformal coatings. First, they are highly durable — which makes them very hard to remove during rework. Secondly, if the the PCB is not cleaned before it is coated, the coating will not adhere tightly to the PCB and the board will not have the anticipated service life.
Conformal coatings are one of those cleaning situations in which it is very difficult to make precise recommendations because there are many, many different types of coatings.