Electronics Forum | Thu May 07 19:29:40 EDT 2009 | kareal
Hi Davef, Do you means it is natural for tin diffusion to copper trace during SMT process? but I could not detect tin in UHAST T=0 unit, and the tin diffusion was found only in copper trace of C4 cage. Two question: 1) Could you tell me which pr
Electronics Forum | Tue Nov 09 23:52:31 EST 1999 | chartrain
Could very well be your nitrogen diffusers are blocked. These have to be cleaned on a regular basis as well.Cleaning frequency for the diffusers is flux dependent as well as other factors but could be as little as one month of operation. Once the dif
Electronics Forum | Mon Sep 20 16:15:11 EDT 2004 | davef
The activation energy for diffusion for molded with novolac, biphenyl or multifunctional epoxy mold compounds and air are not equal.
Electronics Forum | Mon Feb 27 09:09:36 EST 2006 | davef
Silver on your copper or brass part is a solderability protection. The silver diffuses into the solder and you solder to the base metal, either the copper or brass in your case. Soldering to copper is well known. The issues are soldering to brass
Electronics Forum | Fri Sep 08 08:33:17 EDT 2006 | davef
Raybans or diffusers on lights, yer choice.
Electronics Forum | Tue Feb 26 05:10:17 EST 2008 | adetuc
Thanks for the reply Hege, I calibrate the machines every 3 months and have checked that the board carrier to nozzle parralelism is ok. Have tried many different profile settings using a MOLE for readings but still collapsing on one corner. I did
Electronics Forum | Fri Aug 07 10:53:10 EDT 2020 | bukas
brake paint?
Electronics Forum | Thu Nov 10 20:39:44 EST 2022 | SMTA-64386598
The solderability shelf life of ENIG is related almost entirely to diffusion of O2 through the gold plating. When O2 diffuses through the gold, the underlying nickel is oxidized rendering it unsolderable (with ENIG - you solder to Ni, the gold dissol
Electronics Forum | Thu Apr 02 14:58:49 EDT 2009 | vladig
Hi Peter, Have the plating thickness checked with XRF. If the layer of Au too thin, then Ni can diffuse all the way through it during the first run and the surface won't be perfectly solderable for the second side. it might also have a thin layer of
Electronics Forum | Fri May 01 07:22:56 EDT 2009 | kareal
In my project of flip chip PGA production , I found serious delamination in interface of solder mask and first layer copper trace of substrate after UHAST 96hrs( 130C, 85%RH) reliability test. The delamination are always around one type solder bump,
