Electronics Forum: after (Page 41 of 656)

PAD come off from PCB after Rework

Electronics Forum | Wed Apr 19 09:07:44 EDT 2006 | russ

Many times a pad that has no signal trace going to it will come off. It does happen from heat and time as noted before. Somtimes even the best rework person will remove them. If this can not happen in your situation I would recommend that you use

Baking planars after new BGA placed.

Electronics Forum | Mon Aug 14 20:37:03 EDT 2006 | davef

JEDEC defines packaging, matrix trays, tape and reel, and like whatnot. You need to be searching ANSI and IPC. Find these documents: * ANSI/J-STD-020, Moisture/Reflow Sensitivity Classification for Plastic Integrated Circuit Surface Mount Devices *

QFN - FCT failed after reflow

Electronics Forum | Wed Feb 07 09:37:48 EST 2007 | billyd

Had the very same thing happen the first time we used the small QFNs. The aperture for the thermal pad in the center needs to be cut in a grid form, either squares (with around a 10 mil spacing between openings) or circles, like a BGA pattern. Too mu

IC marking unclear after pass reflow

Electronics Forum | Mon Mar 31 09:16:41 EDT 2008 | davef

What is changing the marking on the part? * Is flux residue coating the part to change the the way light reflects from the part surface? [Run a board with tape on the part, then remove the tape prior to AOI] * Is the heat of the oven changing the mar

IC marking unclear after pass reflow

Electronics Forum | Tue Apr 01 12:12:43 EDT 2008 | jdengler

On our machine we have found that some IC's require a different light for inspection based on the manufacturer. Have you tried other lighting options? You may need to talk to the AOI manufacturer to see if there is something the machine may be able

IC marking unclear after pass reflow

Electronics Forum | Wed Apr 02 13:56:03 EDT 2008 | slthomas

So your golden board isn't a valid representation of your production material. I don't use AOI but it sounds like either you need a vendor that can guarantee the same part marking appearance as you originally programmed to (not likely) or you need a

IC marking unclear after pass reflow

Electronics Forum | Wed Apr 02 15:35:27 EDT 2008 | jdengler

Our AOI machine can save various views of the same part number since we all know that different manufacturers will mark parts differently, some manufacturers vary their own marks. We get parts from the same manufacturer but different date codes that

No-clean, water-based flux residues after wave...

Electronics Forum | Tue Feb 03 13:53:41 EST 2009 | allwave

The spec for all PCB suppliers is "solder mask over bare copper using LPI on external layers (green)". The flux we use is No clean 270WR flux (AIM). As far as process parameters, like I mentioned before, same parameters for several suppliers, only on

No-clean, water-based flux residues after wave...

Electronics Forum | Tue Feb 03 15:23:21 EST 2009 | gregoryyork

Hi George This is down to the different cure temperatures used during PCB process. No problem with the flux or your settings You should be seeing a waxy greasy oil like substance on the dirtier board. Or the resist has absorbed the flux residues not

No-clean, water-based flux residues after wave...

Electronics Forum | Wed Feb 04 16:33:40 EST 2009 | davef

Your specification for all PCB suppliers of 'solder mask over bare copper using LPI on external layers (green)' is broad and open to the use of material from many possible LPI suppliers by your board fabricator. In at least one case, it appears that


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