Ask The Expert: Mark Rager, Diamond MT, Subcontract Conformal Coating Service house on Key Conformal Coating Material Challenges

“It’s well known in the electronics industry that cleanliness of a Printed Wiring Board (PWB) is crucial to the assembly’s performance and reliability. What many don’t realise is that the cleanliness of the board is also paramount in adhesion of the conformal coating that may be applied to the board later in the process.”

“Almost all coating material suppliers recommend that you clean and dry the boards prior to coating. However, too often cost is a factor when determining if cleaning is needed. What many do not take into consideration is the affects this has on coating.”
“From a conformal coating house’s perspective this is a very real concern due in part to the compatibility issues that often come about when the coating to which the customer has selected does not adhere to the mold release agents, fluxes, oils, rosins (to name a few) that have been left behind in the manufacturing process. This makes the coating house look bad.”

“Further, its known that contamination of circuit boards can bring about severe degradation of insulation resistance and dielectric strength, which is counterproductive to what some of the characteristics/reasons that conformal coating is used for. You would not want to paint your car without preparing the surface? So then why would one want to do this to such critical/sensitive electronics which are being manufactured?”

“In general, the minimal added cost added for cleaning far outweighs the time and money (when added up) associated with the rework/touchup caused by dewetting issues, missed deliveries and aesthetically unpleasing conformal coating caused by touchup to areas that have dewetting caused in part to contamination on the board. Cleanliness of completed circuit boards is, therefore, of vital interest.”

Visit the Nexus Associate Experts Section and read what other experts have to say about conformal coating material challenges.

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Author: nexus3c

A global resource for the Conformal Coating industry providing information, solutions, connections and advice on all areas of Conformal Coating including Conformal Coating Service, Equipment, Materials, Training, Documentation and Consultancy.

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