Electronics Forum | Fri May 22 15:37:23 EDT 2009 | 1smtdude
Depending on the material chosen, it's possible to �rework� underfilled components. However, it's far from a production process. Two steps are usually required. First: remove the package from the PCB. Second: remove the residual underfill from the P
Electronics Forum | Wed Mar 31 09:44:12 EDT 2010 | bandjwet
One thing I would suggest right off the top is to go to a paste printing process. This will get first pass yields higher (usually 10+% higher than gel flux). If you are suggesting that you have good collapse everywhere, the profile is adequate (soun
Electronics Forum | Sun Jul 06 10:07:03 EDT 2003 | MA/NY DDave
Hi Sam, Great answers so far. Let me take a stab at a few of your questions. Q1. whether this is named Pososity? I can't tell from your description. Several companies and the IPC have porosity tests to see if the Gold has good coverage of the und
Electronics Forum | Wed Dec 19 18:41:33 EST 2007 | darby
You printer is not solely designed for printing solder paste. This is why some of the options you would never use for paste appear in the menu. You may actually be printing overlays or yes, even t-shirts. This is why you may want to flood/print, prin
Electronics Forum | Tue Apr 22 03:46:19 EDT 2008 | fowlerchang
It is CSP reliability issue, which is the mobile CPU from Spreadtrum. All the tests passed and shipped to customer. They assembly them and tested but failed. After they reflow this CSP with hot air gun, some of the boards passed. We got some board
Electronics Forum | Thu Oct 01 07:03:55 EDT 2009 | davef
We doubt that Humiseal 1A33 is causing opens in your assemblies. We'd guess the opens occur earlier in the process, but are not hard failures. So, you pass your tests. When applied, the conformal coat flows into the gap in the ball crack and insulate
Electronics Forum | Mon Jun 28 22:44:13 EDT 2004 | davef
Q1: What is the most popular PCB finish for lead-free soldering ? A1: We'd guess ENIG Q2: Who drives the selection of the finish, assembler or designer ? A2: A tight circle of recrimination, blame letting, and other human ills that is primarily driv
Electronics Forum | Tue May 26 14:42:55 EDT 1998 | Justin Medernach
| We currently bake plastic SMT parts in accordance with the IPC guidelines for moisture sensitive parts. Because we have double-sided boards that are subjected to either an aqueous or semi-aqueous cleaning process, we do a 24 hour bake at 125 deg.
Electronics Forum | Thu Oct 12 16:55:19 EDT 2006 | realchunks
This type of testing is only done to verify your reflow process. It is destructive testing and should not be performed on product reaching your customer. Solder is only used to provide the electrical connection from part to board. As a metal it is
Electronics Forum | Sun Jan 14 16:35:48 EST 2007 | Austin
I have several boards built at various CM's. We have prototype builds with some JTAG failures on BGA's (1-3 failures with qty 3, 1500 pin BGA's). CM's always claim reflow profiles look good. X-ray does not show bridges and they claim it looks good, b
