Electronics Forum | Mon Feb 21 18:13:23 EST 2005 | gpaelmo
As davef states above, you would like to have flat surfaces below 25 mil. We are a contract manufacturer also and we've done thousands of 15 mil QFP's with HASL finish with no problems. Your success will depend on quality of PCB supplier providing th
Electronics Forum | Tue Feb 22 10:44:12 EST 2005 | Dougs
when you talk about stencil design, what would you recommend for aperture size on fine pitch if the customer insists on hasl finish on fine pitch devices? i usually use a 10% reduction on everything we have been using ( 16mil pitch and upwards and 0
Electronics Forum | Sat Oct 07 04:02:50 EDT 2000 | C.J. Long
Good morning, All: I am from PCB shop and one of our customer is experiencing solder bridge on 16 mil pitch QFP( immersion gold finish). Land width requirement is 8 +/- 1 mil measured over top of of land and our mean is 7 mil. Bottom land width is 8
Electronics Forum | Thu Jul 15 18:07:04 EDT 2004 | dwanzek
This has been a tough one to date. Any ideas will help. Problem definition � random QFP144 part not soldering all leads. Percentage fallout is about 1-5% of boards. Usually leads, one or more, on trailing side to the direction of travel does not wet
Electronics Forum | Wed Sep 18 12:31:16 EDT 2002 | dragonslayr
My suggestion is to conduct a Design For Manufacturing (DFM)study on the assembly in question. Pay particular attention to the pad sizes, component lead dimensions and satisfy yourself that those two factors are correct. Given that pads match compone
Electronics Forum | Wed Sep 18 12:35:56 EDT 2002 | stepheno
Fourth - > back to design of PCB. Are there solder dams of > mask between the pads? If yes, that helps. If > not, pay close attention to stencil aperture > width and be sure that the aperture deposits less > paste by 1-2 mils per pad, centered o
Electronics Forum | Tue Feb 15 11:48:30 EST 2000 | Steve Thomas
Thanks for your responses, gentlemen. I'm really just looking at options, and frankly, being a novice at this stuff I'm looking for the info. required to make a semi educated decision. You, kind sirs, are my educators. And that probably scares m
Electronics Forum | Sat Sep 23 15:13:40 EDT 2000 | Francois Racine
Hi Sophia, I`m responsible of SMT line and we solved this problem with a complete automatic solder paste printer machine. In the past we had problem with off alignment and solder height too.... at that time we used a semi-auto printer machine and w
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 | 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
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