Conformal coating should be used when reliability is a concern due the presence of liquid water (condensation), conductive and or corrosive pollution including contaminants from handling, and where dielectric strength needs to be increased for UL trace spacings requirements. Silicones are not vapor barriers, however. ---------- From: TechNet-request To: technet Subject: Fwd: conformal coating Date: Thursday, September 19, 1996 3:49PM On Thu, 19 Sep 1996 13:01:25 -0400 [log in to unmask] wrote: >From: [log in to unmask] (Mark Sattel) >Resent-from: [log in to unmask] >To: [log in to unmask] >Date: 96-09-19 12:40:03 EDT > >Sirs: > >I am presently investigating the need for conformal coatings on our >printed circuit assemblies. Do you have any literature that discusses >the relative merits and disadvantages? To date, our company has >conformal coated 100% of our PCAs. But the cost of masking, spraying, >and unmasking are staggering. My first instinct was to eliminate the >coating except in high heat, high humidity environments. Our operating >environments vary from freezing cold to hot and humid. Any information >that you can supply will be greatly appreciated. I am also very interested in this subject and people's experiences. There's a study being conducted by the circuit card assembly and materials task force of the EMPF (http://www.empf.org) to develope guidelines for the use/non-use of conformal coatings. The study is underway now. I haven't heard of any interim results. Check with them for further details. _________________________________________________________ Gregg Klawson tel: +1.508.880.1822 GTE Government Systems Corp fax: +1.508.880.4316 Taunton, Massachusetts USA email: [log in to unmask] *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************