A Conformal Coating is a protective material that "Conforms" to the varied profile of an electronic circuit assembly. Ideally, it should be UNDER as well as over, the components. The best method of applying a Conformal Coating is by dipping. This method is better able to get underneath devices. Dipping techniques should be: In: < 12 inches per minute so as to ensure that air does not remain trapped beneath components Out: < 6 inches per minute so that the excess material will be pulled off the surface by the surface tension of the material in the tank. Dwell: Only if wound devices are present or where FR2 or paper phenolic substrates are in use. This is to ensure saturation and proper coverage is achieved. Dipping is THE most cost efeective and efficient method of applying any coating material - BUT... The circuit NEEDS to be designed for the coating process. (This is why I posted a question to the Design Forum, to find someone who will include coating as part of the design software, but no-one replied!? Maybe they will now??) Masking is a time consuming pain in the tush and that is why many prefer spraying. If you can persuade your designer to place components that should not be coated, on one side of the assembly, then dipping is cheap, effective and easy. We can dip coat over 200 assemblies per hour using a machine costing only around $12,000.00 You can't achieve these economics with any other method! Paralene is a good product, but the process is worse than dipping: under vacuum (expensive chamber), vapour deposition (extreme masking demands), low volume, long process time. Repair and rework is a major pain in the tush and it absolutely hates being put onto poorly prepared surfaces, dare I say no-clean. Spraying ideally needs to be done in a machine. After all, how do you know someone has coated the board correctly at 9.00am on a Monday morning, 4.00pm on a Friday much less when they have just had a row with their partner?? It becomes necessary to rely on a meniscus around the component shoulder, to seal the underside and good capilarity of the coating to get behind the component legs. Hope this helps Graham Naisbitt ------------------------------------------------------------------ Concoat Ltd Email: [log in to unmask] Alasan House, Albany Park Tel: + 44 (0)1276 691100 Camberley GU15 2PL England Fax: + 44 (0) 1276 691227 -----Original Message----- From: TechNet On Behalf Of Blanchet,Richard Sent: Wednesday, September 24, 1997 5:22 PM To: [log in to unmask] Subject: [TECHNET] FW: [TECHNET] ASSY: Conformal Coating Coverage I've never tried dip coating 1B31 but I heard it does a good coverage if you can control your process steadily. Why don't you consider parylene coating ? With this process, you can cover every areas, however hard to reach they might be. ---------- From: owner-technet To: TechNet Subject: [TECHNET] ASSY: Conformal Coating Coverage