Electronics Forum | Wed Nov 10 16:19:51 EST 2010 | davef
The 5 thou standoff of your SOIC is probably the minimum. We wouldn't be surprised to see 10 thou. With this, you could have maybe a 6 thou gap between printed solder paste and the bottom of the heat slug. So, you're expecting the rabbit ears of p
Electronics Forum | Wed Jul 27 17:01:14 EDT 2005 | Dreamsniper
Issue: At 60'C test PCB Fails. Operator did simulation. Use of Heat Gun to heat up the BGA to 60'C while PCB is powered and running. At 60'C BGA fails. When pressed system is back which means that something becomes open. Sent BGA for SEM and found t
Electronics Forum | Mon Jan 15 11:21:48 EST 2007 | davef
Contractor mantra: * Profile is good * Boards are bad On profiles, the key question is: where did you take the profile? We�d guess cracked connections are giving the intermittent test results when pressing on the components. You use acoustic micro
Electronics Forum | Tue Jun 01 07:26:55 EDT 2004 | johnwnz
Alistair, your paste deposit is controlled by a few things: Stencil thickness Squeegee pressure Squeegee speed Print gap in 99 out of 100 applications for paste printing you would have a print gap of 0 i.e. on contact printing where the PCB is in fu
Electronics Forum | Mon Feb 05 17:18:53 EST 2001 | davef
Wha, Nellie!!! Delamination & Blistering IPC-A-600D Although it may occasionally occur because of a severe process breakdown, delamination and blistering occurs as a result of an inherent weakness of the material. Either condition represents a brea
Electronics Forum | Thu Oct 15 14:23:31 EDT 1998 | Earl Moon
| I have a problem with measling on our PCB's. We saw it on our FR4 PCB's at final assembly yesterday. Is this a defect from the board vendor or something we did in our assembly process when building the PCA's (thru hole). Could the wave solder ma
Electronics Forum | Mon Jun 08 11:39:28 EDT 1998 | Earl Moon
| How do I mechanically/visually inspect BGA devices when they are soldered to a PCB for possible solder, or other, defects as a first step before part removal and further analysis? I have had board failures due to poor soldering--I think? I can pr
Electronics Forum | Wed May 07 21:20:53 EDT 2008 | davef
Causes of Delamination ["Quality Assessment of Printed Circuit Boards" Lund, Preben; Bishop Graphics 1985 0137450354] The reason for delamination is epoxy starvation in the glass cloth layers or an incomplete curing of the base material. It has been
Electronics Forum | Wed Apr 05 22:31:51 EDT 2000 | Dave F
Robert: Out of curiosity, by "BT" do you mean: � Bismaleimide triazine, the stuff used to increase the tg of resins used in some BGA interposers. � British Telecommunications plc, the guys with bad teeth. � BrookTree, the RAMDAC supplier, that�s par
Electronics Forum | Thu Jun 25 14:41:07 EDT 1998 | Earl Moon
| Alright gentlemen and ladies of the forum, I again seek knowlage on what is probably a well known fact. I have spent a good part of the morning with various IPC standards and weighty tomes such as the Electronic Packaging and Interconnection Handb
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