Electronics Forum | Fri Oct 28 08:37:06 EDT 2005 | pavel_murtishev
Once again, it isn�t the process problem. It�s machine problem. I�ve tried to change all of the parameters: printing speed, printing pressure, snap-off speed, snap-off distance, etc. No any effect. Defect still exists with different process parameter
Electronics Forum | Mon Nov 17 14:42:02 EST 2014 | tombstonesmt
Sounds like your snap off profile needs adjustment. More than likely there is paste under the stencil being transferred over to the board. Try adding a cleaning cycle after every board to determine if this is the issue. If the solder balls go away af
Electronics Forum | Wed Sep 01 12:58:42 EDT 2010 | scottp
A good paste will print fine up to 5 in/sec or so. They key, as mentioned, is to get the pressure right for a given squeegee speed. If the squeegees aren't giving a clean wipe then you'll see huge variation in print volume which can lead to shortin
Electronics Forum | Thu Apr 30 13:09:53 EDT 2009 | scottp
One factor I see missing is separation speed (or snap off speed). I've run experiments with different pastes where it was the biggest factor in standard deviation of print volume for small apertures.
Electronics Forum | Wed Apr 14 13:39:08 EDT 2021 | SMTA-64387124
I am working with a CM in Taiwan and we are seeing significant differences between the paste printing bon the forward stroke vs the backward stroke. Print parameters are the same (pressure, speed, snap off speed) but there is a significant difference
Electronics Forum | Fri Oct 28 06:59:45 EDT 2005 | Rob
From what I remember there is a "snap off" setting in the AP25, where you can set the separation speed & I think it may also vibrate the board a little.
Electronics Forum | Fri Dec 20 04:07:25 EST 2002 | Roger
Although everything that has been said earlier is sound advice for achieving good printing results, I strongly believe your problem is your manual printer and its inability to accurately control the speed at which the PCB separates from the stencil a
Electronics Forum | Mon Apr 09 13:28:06 EDT 2001 | slthomas
I've been wondering if I was the only person thinking this. There are so many print parameters that are programmable now on new machines (squeegee pressure, height, speed, snap-off settings, cleaning intervals) that the process would (in my oh-so-hu
Electronics Forum | Thu Aug 12 18:43:49 EDT 1999 | Wayne S.
Hello Having a problem with bridging on 20mil pitch qfp, only on the lead groups where squeegee goes over width of apertures. Using MPM sp-200 semi-auto, chem-etch stencil, 9-10mil width opening 100 durometer blade. Getting "tails" on deposits. Trie
Electronics Forum | Thu Aug 12 20:17:12 EDT 1999 | Kelly Morris
| Hello | | Having a problem with bridging on 20mil pitch qfp, only on the lead groups where squeegee goes over width of apertures. Using MPM sp-200 semi-auto, chem-etch stencil, 9-10mil width opening | 100 durometer blade. Getting "tails" on deposi
