Electronics Forum | Tue Aug 22 11:23:40 EDT 2000 | Dr. Ning-Cheng Lee
Plating houses seem to exhibit various results. Unacceptable Ni oxidation levels appear to be related to poor Pd plating processes. Ni oxidation can occur at 3 process stages: 1) prior to the Pd being applied (Ni already oxidized) 2) during the p
Electronics Forum | Wed Jun 07 11:25:23 EDT 2000 | Dave F
In the portion of Chapter 1 on Flip Chips, Ken Gallio states (1.8.2.1) "tin/lead solder leaching or dissolving gold and form metal compounds, called dendrites, that greatly reduce joint reliability because of high brittleness." What is the compositi
Electronics Forum | Thu May 10 15:48:12 EDT 2001 | kp
Good morning, We are presently using a couple surface mount parts on our circuit boards. We send the boards out of house to have the SMD parts placed. I have been told that the apertures for the stencil for each SMD are not to be 1:1 with
Electronics Forum | Thu May 24 19:19:20 EDT 2001 | davef
Try: * Poor looking solder connections * Good looking solder connections * Reliable solder connections Look to Ch 5 of "Manufacturing Techniques For Surface Mounted Assemblies"; RJ Klein Wassink & MMF Verguld; Electrochemical Pub; ISBN 0-901150-30-4
Electronics Forum | Tue Jul 03 22:18:33 EDT 2001 | davef
Assuming that you are talking about voids in solder connections: * Consider voids on the surface of your solder connection a defect. * Consider voids that you can't see to be a process indicator. See A-610C, 12.4.8 for authoritative guidance.
Electronics Forum | Mon Jul 23 20:28:17 EDT 2001 | davef
We run both NC and OA flux, although the majority of our product is run on OA. For application not requiring uBGA, we find the benefits of NC elusive, at best. What? .... Your customer recognizes that initially the NC res in non-ionic, but sticky.
Electronics Forum | Wed Jan 26 21:16:28 EST 2000 | Dave F
Mark: It sound like one or more of the following is happening: * Previous heat cycles (ie, reflow, reflow, wave) are degrading the surface protectant * Wire solder flux doesn't have enough stomp to burn through the corrosion. That poor ol' stuff
Electronics Forum | Mon Jan 31 21:11:09 EST 2000 | Dave F
Dave: Find: "Comprehensive Surface Mount Reliability Model Covering Several Generations of Packaging and Assembly Technology", by J. Clech et.al. IEEE Trans on Comp. Hyb. and Manuf. Tech. Vol. 16, No. 8 Dec. 1993, p.949. It listed cycle to failure
Electronics Forum | Fri Jan 14 16:48:40 EST 2000 | Steve Thomas
O.K., folks, I know this is a loaded question, but I've been asked to find the answer, sooooo: What is an acceptable defect rate in ppm for a surface mount process, assuming that each component has the potential for one defect. This would include de
Electronics Forum | Wed Jan 05 06:55:48 EST 2000 | Mark Alder
Please go into s.m.t.net archives 19/2/1999 and have alook at the suggestions I received.I have found them to be fairly accurate and work pretty good.Lazer cut stencils also made a significant improvement.The adhesive I used was AMICON D125F3 from Em
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