Electronics Forum | Mon Nov 12 09:37:17 EST 2007 | russ
You need to perform process a capability study prior to putting these controls into place. Cleaning a stencil after each pass will get ugly, solvent residues remaining in apertures etc. 2D inspection is good. Change paste every hour will get very
Electronics Forum | Sat Aug 04 07:44:25 EDT 2007 | davef
Thermal cycle* * Requirements for and troubleshooting of poor barrel fill => Hole fill
Electronics Forum | Wed Sep 05 08:10:45 EDT 2007 | davef
Questions are: * Do not judge the quality of a solder connection by the shineyness or color of the solder connection. Do you have smooth and unform flow, no pitting, and good wetting to the lead and the pad? * What is the temperature of the leads of
Electronics Forum | Tue Jan 13 22:43:11 EST 2004 | davef
We have seen this in reflowed parts, where there is flux res collected in the dimple in the solder, where the lead 'presses' in the solder. Generally, we attack this as a thermal issue: * Thermal pads sucking the heat away from the leads. * Leads no
Electronics Forum | Mon Feb 02 05:08:37 EST 2004 | heccles
Anybody seen problems with potted trimpots and reflow soldering - specifically poor wetting as a consequence of lead contamination from the potting compound. Regardless of reflow profile used (MIL -STD -202) cannot get a good joint formed ! If you us
Electronics Forum | Thu Jan 02 08:04:06 EST 2020 | philc
You might want to try baking the LED's in an oven for 24 hours prior to build. We keep our LED's in a humidity cabinet all the time, as we have noticed poor solderability if they are left out for too long. This may be even more important when buying
Electronics Forum | Mon Jul 30 21:07:35 EDT 2001 | davef
So, yer loosing parts between place and reflow? That would seem to say yer: * Paste has lost tackiness [check the fine SMTnet Archives for a sample test.]. * Really not placing the parts that you think yer placing. * Knocking the parts out of place
Electronics Forum | Thu Mar 31 19:52:50 EST 2005 | davef
We agree with Russ that you're talking palladium instead of platinum. Your wetting problem likely is not the Pd-Ag surface layers, but the underlying metal or nickel to which you need to wet. Either a base metal is: * Contaminated and poorly wettabl
Electronics Forum | Thu Sep 06 16:58:40 EDT 2007 | gregoryyork
are you sure it isnt down to an hygroscopic contaminant causing the problem.I've only ever seen it once or twice in gold,really quite unusual.Its not too much gold brightner or similar residue.If it can be cleaned off then it shouldnt be there so it
Electronics Forum | Wed Sep 05 07:07:25 EDT 2007 | mun4o
hi, I have a big problem with soldering uP QFP144 package.All components in PCB are small, only this chip is big and I can't make good temperature profile.Solder joints of other components are shining and with good wetting, but in QFP leads solder j
