Electronics Forum | Tue Feb 28 20:56:12 EST 2006 | davef
Here you go ... PCB FR-4 Inspection Manual 1 Introduction This defines the minimum acceptability requirements. It is not intended for use as a performance specification for the Company or procurement. It is based on the requirements of Acceptabi
Electronics Forum | Thu Apr 17 10:44:24 EDT 2008 | rculpepp
I'd suspect contamination also, possibly from the board supplier. Sr. Tech's post mentioned what looks like a blister on the board, in the upper right of the Q19 photo. This could very well be a contaminate from the PWB fab shop. I've seen similar 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 | Tue Jul 15 16:12:23 EDT 2008 | boardhouse
Hi Armynski, I sell for an offshore board house, yes, it is common for offshore board shops to fill vias. The bubble is caused by air entrampment within the hole it self, when heat is applied during Hot air and the via is covered on both sides the e
Electronics Forum | Thu Dec 04 09:49:11 EST 2008 | lazzara55
Dear Steven: Often the recommendations for baking prior to assembly are derived from various J-stds. But J's currently concern baking moisture out of components, and fail to address the moisture issues of the PCB. Because of that, there is the IPC D
Electronics Forum | Fri May 07 00:52:24 EDT 2010 | boardhouse
Hi Derek, just curious of one thing - are the vias within the BGA's the only vias covered or are all vias on the board covered. Just trying to figure out what is making this area different from the rest of the board. Regarding leaching, I do not be
Electronics Forum | Mon Aug 18 15:04:25 EDT 2014 | rgduval
Off hand, I can't recall a "formula" for how long boards could sit in a specific RH environment. I've done a couple of quick Google searches, and can find a bunch of information on the dispersion rate of moisture in various PCB materials, but, nothi
Electronics Forum | Sun Jul 26 07:52:35 EDT 2020 | sync40
Hello to everyone, Have you ever experienced soldermask bubbles inmediately after printed the soldermask itself? (for screen printing method of LPISM). I am not talking here about blistering or any outgassing defects after exposing to high temperatu
Electronics Forum | Fri Aug 29 09:39:08 EDT 2014 | rgduval
I'll try to deal with the issues as you've presented them. 1. Blistering/delamination, shown in photo 2. The most likely cause of blistering/delamination like this is moisture in the boards. The moisture can get into the boards in multiple ways..
Electronics Forum | Wed Jan 05 11:11:09 EST 2000 | Dave F
Hey Pat: My responses are: 1. Does anyone have experience with the shelf life on immersion white tin? If so, how long can the boards be stored without adversely affecting solderability. I've heard one year. No, we don�t, because we turn boards fa
