Electronics Forum: qfp float (Page 1 of 2)

Double Sided Reflow

Electronics Forum | Thu Mar 17 10:30:06 EST 2005 | davef

This happens. You may need to put a dot of chip bonder on the corner of the floating QFP after first pass. What size are the QFP that are moving?

Larger lands in corners

Electronics Forum | Thu Jan 10 18:32:20 EST 2008 | stevek

Our layout guy recently started making land patterns with the corner lands oversized. These are for leadless and various flatpack parts. He claims this is to improve manufacturing. I had seen a few boards with this just as I got out of the CM worl

Floating 144-pin QFPs

Electronics Forum | Fri Nov 13 03:57:41 EST 1998 | Steve Cheung

We are experiencing 'lifting' on one or more sides of a QFP. Poor lead co-planarity has been ruled out by independent tests. Please tell me which of the two remaining failure modes is the most probrable? 1. Expansion of gases in vias underneath devi

MQFP soldering issues - how can I improve?

Electronics Forum | Mon Aug 22 13:28:47 EDT 2011 | scottp

No, don't put weight on it. If the part is really "floating" on the solder and not wetting properly and the solderability looks good on all your other parts then I'd suspect a part problem. Get with the QFP supplier and make sure the Sn isn't too t

QFP soldering issue

Electronics Forum | Thu Jan 08 16:16:09 EST 2004 | Dean

My first concern would be the choice of solder paste you have. There are better chemistries out there that far exceed the capabilities of the 609 2. Yes, the part will partially float on the solder (assuming plastic qfp). Cross sectioning would sho

Re: Floating 144-pin QFPs

Electronics Forum | Thu Nov 19 05:25:07 EST 1998 | karlin

We are experiencing 'lifting' on one or more sides of a QFP. Poor lead co-planarity has been ruled out by independent tests. Please tell me which of the two remaining failure modes is the most probrable? 1. Expansion of gases in vias und

QFP soldering issue

Electronics Forum | Thu Jan 08 15:03:40 EST 2004 | dwzeek

We have an ongoing problem with our QFP144 packages soldering. It has not received much attention until late due to some customer failures. Most of the failures would show up in ESS testing and be repaired. The failure rate is about 2 in 1000 parts f

Re: 8 mil placement, part Deaux!!

Electronics Forum | Fri Sep 11 14:39:02 EDT 1998 | Earl Moon

Thanks to all Earl, Mathew and David for the SMT info. I have one more question. Does anybody have a chart listing the standard, industrial spacings? Perhaps listing in each unit, say XX mils = XX Pitch. Or XX mils = XXmm or something of that n

Re: Floating 144-pin QFPs

Electronics Forum | Fri Nov 13 09:55:08 EST 1998 | Chrys

We are experiencing 'lifting' on one or more sides of a QFP. Poor lead co-planarity has been ruled out by independent tests. Please tell me which of the two remaining failure modes is the most probrable? 1. Expansion of gases in vias underneat

Re: Detecting lifted leads on QFPs

Electronics Forum | Sun May 30 08:50:42 EDT 1999 | Dave F

Yes l know this problem keeps cropping up on the forum but l've missed some of the follow-ups. Our problem is that the lifting only occurs on 3% of production so actually detecting an improvement is difficult. We're actually having to inspect

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