The Conformal Coating Process: An In-Depth Review
Posted by Sean Horn
Wednesday, April 11, 2012 10:21
@ 10:21 AM
Conformal Coating Process – Phase 1 – Prior to Parts Arrival
Once we receive a purchase order from a customer, all of the pertinent information such as drawings, specifications, and special instructions are given to the quality department from our marketing team to create custom work instructions for that particular part. If the material to be used has not yet been determined, we work with the customer to determine the best material for their application.
Conformal Coating Process – Phase 2 – Coating Processes
After the work instructions and other administrative tasks have been completed, the parylene coating production process truly begins in our shipping department. Once all of the items have been unpacked, they are then routed to incoming inspection. Here, parts are counted to verify quantity against the customer purchase order and packing slip, as well as inspected to verify that no damage occurred to the assemblies prior to arrival at Diamond-MT. After incoming inspection, assemblies are then ready for individual processes. For example, if cleaning or cleanliness testing were required, it would be performed at this time. Once any unique processes have been completed, the products are then routed to masking. Masking is done in accordance with the customer’s drawings and requests for coating keep-out areas. Once completed, the parts go into masking inspection to verify compliance with the customer’s masking drawing.
After parts pass masking inspection, they are then to be coated. The coating is applied via spray, dip, or brush. Once the coating has been applied, the PCB’s have the masking material removed using great care not to damage the conformal coating applied. The assemblies are then routed to the touchup room, where areas damaged by de-mask are repaired and coating is added to other areas of the board that were initially covered by masking. Sometimes areas of the board need to be covered by masking to ensure connectors don’t flood, but the leads of the connector need to be coated. This is remedied in the touchup rom.
Once touchup is complete, a 100% coating inspection is performed to ensure that the coating is in accordance with the customer’s drawing. After the boards pass coating inspection, the coating is then fully cured to the manufacturer’s specifications. After cure, all parts are subject to a final inspection, then finally packed and shipped in the boxes they came in. This is usually a five business day evolution, but can be completed quicker on a negotiated basis.
Conformal Coating Process – Phase 3 – Post Coating Follow-up
Our marketing team is in very close contact with our customers after the coating process to make sure the coating is exactly as the customer requires. If any changes are necessary to our process, our quality department will work hand in hand with the customer to make sure that the end product is exactly what is needed.
Photo courtesy of the U.S. Army