Electronics Forum | Mon Jul 23 16:21:54 EDT 2007 | mleber
We have used many ways of measuring but all are either messy, inconsistent or time consuming. We have done wet, glass slide dry, etc. We are currently using a kapton tape dot system. Spray the board, remove the dot and measure it, subtract the thick
Electronics Forum | Thu Mar 27 08:05:20 EDT 2008 | davef
Search the SMTnet Archives for threads like: http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=6753 where J Medernach says, "Make sure your supplier uses some sort of process control of coating thickness. If they don't have a photospectromete
Electronics Forum | Mon Jul 23 11:44:40 EDT 2007 | davef
NASA-STD-8739.1, 10.2.3 Thickness Measurements. Thickness measurements shall be made on coupons processed at the same time and under the same conditions as the PWA. The coupon substrate may be any compatible rigid material with a smooth flat surface.
Electronics Forum | Tue Jan 24 21:07:17 EST 2006 | davef
We all genuflect to Graham Naisbitt, a generous contributor to SMTnet. Moisture-curing urethanes may form minute bubbles if the coating is too thick or the coating environment is too humid. So, tell us more about your urethane and the method you u
Electronics Forum | Thu Aug 27 11:35:07 EDT 2009 | davef
There are many possibilities: * Conformal coat is incompatible with surface residue on the board * Conformal coat is incompatible with solder mask on the board * Moisture is out-gassing from the board * Conformal coat is too thick and does not allow
Electronics Forum | Thu Aug 13 19:30:57 EDT 2009 | secura1
I'm new to all this... we have a board with one BGA blue tooth device. one test for the board is an rf test that measure successful packet transmission. we find that we get much lower error rates if we "reflow" the BGA with a heatgun. We do this
Electronics Forum | Sat Sep 25 08:59:59 EDT 2004 | davef
IPC-HDBK-830, Guidelines for Design, Selection and Application of Conformal Coatings says: A conformal coating may have several functions depending on the type of application. The most common are: * Inhibit current leakage and short circuit due to h
Electronics Forum | Tue Nov 25 14:12:17 EST 2008 | mikesewell
I've used handheld ultrasonic gages on silicone in the 4-12 mil range. A coupling agent is needed between the transducer and the material - we used DI water vs. the supplied gel. Fairly straightforward, setup is done off a reference thickness of ma
Electronics Forum | Thu Jul 30 14:13:00 EDT 2020 | emeto
Same line of thinking with Pete here. Why thin board and thick coating? Did you consider to use underfill instead?
Electronics Forum | Wed Aug 27 08:06:43 EDT 2008 | davef
Thick, hard conformal coatings of acrylic, urethane and epoxy have a well documented history of causing solder joint cracks and breaking glass/ceramic and other brittle components. Dissimilar expansion and fairly high surface bond strengths of the ma
