Electronics Forum | Fri Apr 12 17:22:47 EDT 2002 | davef
First, splitting hairs on parlance. * Conformal Coating. A thin electrically nonconductive protective coating that conforms to the configuration of the covered assembly to provide environmental and mechanical protection. * Solder Mask. Coating mate
Electronics Forum | Sun Sep 28 17:14:53 EDT 2008 | ronsou
small pads like 0402 tend to get hot quite > easily. looks like excessive heat is your problem > here. pads are wetted, component leads are not. > this means solder paste flux on top layer was > exhausted before entering in reflow. your profile
Electronics Forum | Thu May 26 16:41:00 EDT 2011 | scottp
Here's what I do: - Test Surface Insulation Resistance (we're in the high reliability market and use a test significantly harder than IPC's). I also test SIR in combination with other assembly materials like conformal coatings and wave solder flux
Electronics Forum | Fri Mar 17 07:51:49 EST 2000 | Peter Barton
John, I have had previous experience of immersion silver coated PCB's in place of HASL coated type using no-clean processing with little or no problem at all. All of the process parameters were left unchanged. There is a very minor difference in th
Electronics Forum | Thu Feb 17 11:38:53 EST 2000 | Steve Thomas
We appear to have solved a major reflow process problem (poor quality joints on a 20 mil QFP100...excessive solder left on the lead leg, not much left for a joint) with a design change to the board. We gave ourselves considerably more room for a hee
Electronics Forum | Sat Feb 12 09:08:47 EST 2000 | Sal
Experiencing a problem with a 208 PBGA device. I am achieving good wetting with the exception of one ( damn) pin on the outer corner.I have a really good profile but the worrying thing is that it is so inconsistant. Once this open pin failure is dete
Electronics Forum | Fri Jan 12 16:35:00 EST 2001 | Steve Thomas
I've got a question: Can a joint look good externally, even under 45X magnification, and not be mechanically and/or electrically sound? I thought that if the wetting angles were sufficient, there's no discoloration from extreme thermal distress, or
Electronics Forum | Fri Dec 15 08:00:57 EST 2000 | Pete B
John, We regularly wave solder electroless silver finished boards (Alpha Level)with mixed SMD and through hole parts and do not have any problems. We have changed a number on PCB's from HASL to electroless silver, mainly for the benefits at SMD whe
Electronics Forum | Mon Nov 06 09:38:55 EST 2000 | Dean Stadem
We have seen this problem several times. It always goes back to pad solderability, very seldom does it have anything to do with ball size. If there is no evidence of wetting on that pad, but all of the other pads did solder, you need to ask yourself
Electronics Forum | Fri Oct 27 10:35:36 EDT 2000 | Chris
We are having problems soldering this motorola part(XPC860TZP50B5). After reflow, some of the balls appear to be sitting on the reflowed paste rather than wetted to it. We reviewed parts and found oxidation on many. We have four other BGA's, from oth
