Electronics Forum | Thu Apr 22 20:26:39 EDT 1999 | Dave F
| | On various PCB's after building processes,such as reflow, flowsolder and wash. The soldermask on the PCB's have become discoloured, like a 'marble' effect all along the solder side of the board, it is lighter in contrast than normal, although whe
Electronics Forum | Fri Jun 07 11:39:33 EDT 2019 | gregoryyork
I feared so. The only thing to be done is to tell the PCB manufacturer to increase the Thermal cure so dont set the oven to 150C but to 170C and actually measure the middle board and once it hits 155C then give it an hour cure from then. Also insist
Electronics Forum | Fri Jun 07 05:08:08 EDT 2019 | gregoryyork
Does look like delam, if its that bad and the board looks like its HASL finish or Silver, it could also be porous absorbing the chemistries of HASL or Nitric from the Silver which will greatly encourage ECM or poor SIR figures or just simply eat the
Electronics Forum | Wed Mar 19 08:38:13 EDT 2014 | davef
I can't picture much of what you're saying, not for nothing, I'm just not connecting. During assembly, solder mask can affected by heat and chemicals. Typically this would be during: * Soldering * Cleaning I will tell you this: Not to defend assem
Electronics Forum | Tue Mar 25 13:55:05 EDT 2014 | horchak
Ok lets put it this way. If the PCB house used a high quality mask and properly applied it to a properly cleaned surface and properly cured it, then as Dave stated above there are only two things that can destroy it. Excessive heat and overly aggress
Electronics Forum | Fri Nov 18 12:09:37 EST 2022 | jauregui
Hello friends! Is there a method to remove cured soldermask? Area is localized, intent is to solder SMDs parts. Boards are populated. Typically, we use an exacto knife with some risk of course but these boards are pricy and it's alot that needs
Electronics Forum | Thu Jul 14 19:12:40 EDT 2005 | sync40
Hi. In the past years I had made dozens of PCBs but now I am trying to get a professional finishing on them. The main problem is oxidation of the copper traces. Basically I use the silkscreen method to make the pattern in both layers and then etch. L
Electronics Forum | Mon Jun 25 03:52:24 EDT 2012 | awtm
Our Customer had detected tarnished pad on ImAg PCBA and had conducted several SEM-EDX test at the soldermask below some of the chip resistors. High concentration of sulfur was found and it can be significantly reduced after further chemical cleaned
Electronics Forum | Thu Jan 28 20:00:54 EST 1999 | Dave F
| Okay, | | Another question, if the soldermask in not cured, then it is washed will water ingress (from wash or ambient ) play havoc with capacitance or dielectric of PCB. I mean will my crystal and clock circuits start "Y2K'n" on me. OR will my P
Electronics Forum | Mon Apr 12 19:28:26 EDT 1999 | Tom B
Netters, When I reflow a PCB there is a discoloration of silkscreen and mask. It appears if Profile is too hot! But I dont think so, maybe I'm wrong? 1. Kester 293 no clean 2. 2.1 C/s for 30s to 150 C 3. .5 - .7 C/s for 60s to 185 C 4. 1.5 C/s u
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