Electronics Forum | Thu May 29 17:19:51 EDT 2008 | dyoungquist
On 0402s we use 20x25 mil pads with a 15 mil gap between the pads on the pcb with ENIG finish, 5 mil stencil with a 1:1 aperture (20x25 mil) and SAC305 lead free solder paste. We very rarely see any tombstoning on 0402s using this setup.
Electronics Forum | Fri Oct 17 22:36:35 EDT 2008 | arosario
Hi All, We just started build a new product and I am encountering many non-wet rejects in our new product. I need help on what should I look into to improve our Yield. Please see below back ground 1. We are using DEK Infinity as printer. 2. We are mo
Electronics Forum | Fri Oct 24 13:21:12 EDT 2008 | evtimov
Hello Bong, I would make one test only. Make one batch using the problem part from a different vendor. That will answer your main question. For me the part is causing all your problems. If it is possible, change it. Last time having problem like you
Electronics Forum | Tue Dec 21 12:28:27 EST 2010 | wrongway
I know when we used them we had problems when one pad is 7 mils tall nest to a flat pad one lead touches the pad the lead next to it isnt touching anything so then have an open I don't see how anybody dosnt have problems with it that use quad flatpa
Electronics Forum | Fri Jul 06 13:44:15 EDT 2007 | shrek
Krikies! seems like a head-scratcher if I may say so me-self. I would say the other ogre is right, that surface finish will play a big factor in your solder joint's grain structure or how shiney 'tis. Non-HASL bearing finishes will typicaly exhibit
Electronics Forum | Tue Apr 24 02:56:12 EDT 2007 | chrispy1963
If the PCB you are using is a HASL pad finish and is a leaded assembly, we use homeplate pads with a 5 mil stencil. If the circuit has Enig finish and is PB-Free then we use 1:1 apertures with a 5 mil stencil Either method should provide no solde
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 | Thu Aug 12 22:38:44 EDT 1999 | Dave F
| Hello | | Having a problem with bridging on 20mil pitch qfp, only on the lead groups where squeegee goes over width of apertures. Using MPM sp-200 semi-auto, chem-etch stencil, 9-10mil width opening | 100 durometer blade. Getting "tails" on deposi
Electronics Forum | Tue Dec 21 11:49:33 EST 2010 | remullis
1st the buyer shouldn't control the process based on cost. Let them buy stuff and stick to that. 2nd, I do think leveling in th HASL process is important. If you have high spots on pads for fine pitch your wiping away more of that aperture than othe
Electronics Forum | Tue Dec 21 04:09:49 EST 2010 | johanhuizing
0.5 and 0.4 mm pitch, we think we could get problems with the solderpaste stencil. Also some board have keypads and then we have do do partial gold and I think that will not reduce the costs
