Electronics Forum | Sun Nov 24 09:54:24 EST 2002 | davef
On a HASL board that has poor wetting on the pad, consider looking further downstream in the process than your assembly shop. For instance, take a look at the bare boards. Look for solder mask bleed onto the pads. This will show-up on the outside
Electronics Forum | Fri May 09 14:40:38 EDT 2014 | hegemon
I might start with the equivalent 4 or 5 mil stencil and 1:1 on the apertures. If voids are too prevalent, then I would tin the pads of the device, remove the solder, and then solder as above. You may have another hurdle, in that the resulting stan
Electronics Forum | Fri Nov 22 05:04:07 EST 2019 | SMTA-Matthew
We have some circuit boards where the solder mask seems clear instead of green on top of some of the tented via pads. No gold deposited during the ENiG process and no solder sticks to it but why is it clear and does it have any correlation to the thi
Electronics Forum | Fri Nov 22 16:19:45 EST 2019 | davef
I'd guess ... + Pads have no solder mask, clear or otherwise. + Pads won't take solder, because you're trying to solder to nickel. + Nickel on the pads is oxidized and is sticking out its tongue at the flux you're using. + Something went south
Electronics Forum | Mon Nov 06 14:21:09 EST 2000 | Kevin
Masking thickness can also play a factor in tombstoning (or the Manhattan Effect). If the pad is 2 mils or more below the surface of the masking this can create a problem. Depending on the thickness of the solderpaste deposition, the solder height
Electronics Forum | Thu Jul 10 09:55:47 EDT 2003 | davef
A reading of the pictures is: A1: Looks like pad [B1] is smaller than the other pads. It�s weird that the pads are such different colors. A2: Looks like pad [B1] is smaller than the other pads. Solder mask opening [B1] is misregistered and seems s
Electronics Forum | Wed Jul 09 16:01:10 EDT 2003 | russ
Mike, the one pad that is "small" definitely appears to be over etching (It looks like it was supposed to be much larger). What is the dims of this little bugger as compared to the Gerber? i would also tend to believe that there probably is some mask
Electronics Forum | Wed Jun 18 20:27:28 EDT 2008 | davef
No, we not sure if your solder mask is LPI. The article we linked was aimed at solder mask application methods. LPI is the most common mask in use today. So, what kind is it? Green tells you nothing. Solder mask can be a variety of colors.
Electronics Forum | Wed Jun 18 08:57:45 EDT 2008 | more_sunshine
thanks for the post... but are you sure that the type of mask i mentioned is photoimageable and as i understood can be removed from desired places (pads/soldering areas) using uv and developer (which i don't know what material is it). and also the
Electronics Forum | Thu Jun 19 04:16:11 EDT 2008 | more_sunshine
actually this is my little problem, i don't know about the material except that it comes in a paste form and it has to be diluted with acetone and it has a green color. i wish that the compounds used to make a solder mask aren't that numerous to be d
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