Electronics Forum: soldering problems with qfn (Page 8 of 36)

QFN84 Solder Printing Issue (QFN with Inner LGA Pad)

Electronics Forum | Fri Dec 01 09:29:36 EST 2017 | kojotssss

Hello. We have a problem with QFN type. Component is elevated. Stencils are reduced. Vias is without holes. What are the solutions to fix the fault. Look at the photo. Attachment: https://drive.google.com/open?id=1OIgaXUz2yoKP3fWZg2rUsrmZMBWidk6_

problem with vapor phase

Electronics Forum | Wed Jul 10 14:29:27 EDT 2013 | isd_jwendell

You wouldn't have a very good profile if you went straight from room temp to vapor temp (_-). The chamber should preheat the board before using vapor to melt the solder.

problem with vapor phase

Electronics Forum | Mon Aug 12 15:56:13 EDT 2013 | pjchonis

Vapor phase soldering systems by Asscon are characterized by special designed heating modules. The thermal mass of the heating modules is designed so that a completely delay-less and direct regulation of the heat/flow/energy transfer to the soldering

Voids with LGAs

Electronics Forum | Fri Jan 18 12:34:14 EST 2013 | duchoang

Yes, I have. think I have pretty good reflow profile. We use Lead-Free,No-Clean,SAC305 Solder Paste. The problem is at LGA design.The pad size is alot bigger than BGA. They are totally flat and do not have balls/spheres which melted and collapsed thr

Problem with conformal coating

Electronics Forum | Wed Feb 23 22:38:28 EST 2005 | davef

We: * Cure 1B73 according to spec in a heat box, like a Blue-M * Clean nozzles [one set in use, one set being cleaned] in thinner in a bronson ultrasonic cleaner * Haven't evaluated coatings in years, but would do it according to J-STD-001C, Reqmnts

Problem with flux

Electronics Forum | Thu Aug 20 14:52:40 EDT 2009 | davef

Armando: We're guessing that the white residue is on the laminate also. We believe that the residue has something to do with your low residue flux and water. It could be: * Water contamination in the flux. * Poor selection of preheat temperature that

Board with immersion Tin

Electronics Forum | Mon Nov 25 07:58:27 EST 2002 | Yannick

Hi, I made a board wich I plated with immersion Tin, I tought it should be the same result as we had with tin lead but we ran into a weird problem. WE use a 63/37 no clean paste and on the Board with Immersion Tin the solder just make a ball ON

Gold Flash with QFN28 problem

Electronics Forum | Dan |

Thu Mar 30 08:58:20 EST 2006

Problem with shielding component

Electronics Forum | Tue Jan 09 13:01:17 EST 2007 | stepheniii

Not unless it's a case of "the only difference is..." What I mean by that is more than once I've been told the only difference in a new rev is one component or one change. But the truth was that was the only reason for the change, and in fact there

Re: coating with no-clean?

Electronics Forum | Thu Jan 13 15:19:51 EST 2000 | Dave F

Hey Jack: It's certainly "do-able." Conformal coating adhesion testing was done as part of the "Evaluation of Low Residue Soldering for Military and Commercial Applications: A Report from the Low Residue Soldering Task Force," published by Sandia Na


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