Electronics Forum | Sat May 12 00:04:36 EDT 2001 | zam_bri
The product I'm running currently consist a mix of 20 mil pitch QFP, 50 mil pitch, 0402, BGA and variable size of connectors from small to big, on OSP finished PCB. Running intrusive reflow with a mix packages is a real headache, esplly when you hav
Electronics Forum | Mon May 14 17:12:20 EDT 2001 | davef
Continuing along the path that Brian took ... IPC-7525 gives design guideline for stepped stencils. It goes something like: * Stepped area SB GT 25 thou from pads located on the greatest thickness of the stencil * Pads in stepped area SB GT 35 tho
Electronics Forum | Sun Sep 27 11:41:13 EDT 2009 | rajeshwara
We are using ST Demodulator QFP in our product which have exposed pad / heatsink from bottom side. Visually or in magnifier the solder joint or fillet looks good but if we touch up the pins with soldering guns , PCB works fine.
Electronics Forum | Tue Dec 14 12:00:34 EST 1999 | Kris Wiederhold
We recently reduced our standard aperture reduction to aid in the reduction of solder on gold defects. Since this reduction in aperture size, we have been experiencing exposed copper at the end of the component pads. The heel and toe joints are per
Electronics Forum | Mon Oct 23 06:51:36 EDT 2000 | fastech6
I have a problem with solder getting into exposed gold pads. What is the best rework procedure for removing the solder and restoring the gold condition of the pad? At the moment, we are also covering the gold pad with kapton tape prior to solder
Electronics Forum | Thu Jul 05 15:13:46 EDT 2007 | joeherz
We've seen non-functional QFNs cured by touching up the toe fillets. Especially with parts that are not plated on the edge/face where you get minimal/no wetting due to oxidation of bare copper. I'm not suggesting that you touch everything up but th
Electronics Forum | Wed Feb 21 21:01:57 EST 2007 | davef
Yes. Heat reduces OSP solderability protection thickness. For instance, many OSP are shot at the end of the first reflow pass and the exposed copper is free to oxidize. If you're speedy, you can pull-off the second reflow cycle before the copper g
Electronics Forum | Mon Sep 28 16:15:57 EDT 2009 | davef
That your solder connections reflow properly when heated with a soldering iron, indicates that that your reflow recipe needs improvement. * Thermocouple the pads that require touch-up and adjust your oven recipe to assure that they reach liquidous+20
Electronics Forum | Fri Aug 20 12:41:20 EDT 1999 | stefano bolleri
| | Yesterday as I was creating a profile on a plastic BGA using Conceptronics freedom 2000 rework station, I happend to discover that I was able to remove solder bridging from a plastic BGA. | | | | This is what I did. | | | | Created a removal pr
Electronics Forum | Tue Mar 14 21:22:41 EST 2000 | Dave F
Bingo!!! By panelizing and adding breakaway rails (as Nancy says), Stuart can pour copper up to his board fab's tolerance from the board edge. Traditionally, he just wants to make sure no copper shows on the edge of the board. Then again, it's his
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