Electronics Forum | Fri Jan 21 06:35:51 EST 2022 | stivais
"Manual washing" of a misprint board basically is smearing of printed solder paste all over the board. And trying to remove (wipe off) it afterwards. So for me it would not be any surprise that the solder paste ended up on the pads where it was not i
Electronics Forum | Wed Oct 19 07:44:33 EDT 2005 | davef
When a hole is drilled during board fabrication, it can transfer resin from the base material (eg, FR4 core or prepreg) to cover the exposed edge of conductive material in the wall of a drilled hole. This is called resin smear. Etchback is a control
Electronics Forum | Tue Jun 13 04:20:21 EDT 2006 | Grant
Hi, ok, I have a bit more info after playing further with the profiling. We are getting close, but we don't have enough top side heat I think. The IR lamps just don't give enough, but we can get better connector that should help. But we have anoth
Electronics Forum | Sat Jan 26 21:33:39 EST 2013 | sarason
Looks like you have a carbon black process that isn't quite plating to completion, pin prick size holes have remained in the plating. When dipped in an etchant (ie any acid or H2O) the holes grow and they leak carbon. This may be more of a problem th
Electronics Forum | Thu Oct 23 09:45:05 EDT 2014 | rgduval
Generally, excess solder balls found randomly around the board/parts points to either a dirty stencil during printing, or a stencil/board that is shifting during printing (smearing the paste a little, and causing a dirty stencil. If the apertures ar
Electronics Forum | Mon Mar 13 15:35:32 EST 2000 | Ioan
Stu, it is good you know that there are limitations and you want everything. Wish our designers work like that. So, the limitations we impose are dictated by the rails of the insertion and dispensing machines. Normally a .150" keepout will make a s
Electronics Forum | Mon Mar 13 15:35:32 EST 2000 | Ioan
Stu, it is good you know that there are limitations and you want everything. Wish our designers work like that. So, the limitations we impose are dictated by the rails of the insertion and dispensing machines. Normally a .150" keepout will make a s
Electronics Forum | Thu Jul 03 15:29:46 EDT 2003 | bpan
Hello Jim, We build boards that have traces under the parts all the time. For the most part, we have no problems but on one product we have an 0805 that bridges 2 traces with a very tight seperation and if any solder smears (under the part)we can and
Electronics Forum | Mon Jun 27 09:38:30 EDT 2005 | Bob R.
What problems are the quality people seeing? I hope they aren't expecting a toe fillet. QFNs are typically cut from an array after plating. This leaves exposed copper on the sides of the part. We'll often see smearing from the sawing process that
Electronics Forum | Mon May 01 14:30:14 EDT 2006 | marvindamaniac
I know from previous experiences that off contact printing have helped us reduce bridges and smears under the stencil. I am looking for ANY documentation regarding this topic in order to try to implement a change at our current factory. If anyone ha
