Electronics Forum | Thu Jun 16 09:13:46 EDT 2005 | russ
We use a 5 mil for 16mil pitch QFPs, Make sure that the stencil has been polished. Type 3 paste. We have used lead free no-clean, lead no-clean, and water soluble lead pastes for these packages. We set the printer for a slow stroke .7 in/min. wi
Electronics Forum | Thu Jun 16 22:14:51 EDT 2005 | davef
16 thou pitch parts: Use a 5 thou laser cut electropolished stencil with 0.008"x0.045" apertures and type 3 solder paste. Bridges Connecting or Partially Connecting Adjacent Leads or Lands * Excessive solder paste * Excessive component placement pre
Electronics Forum | Wed May 17 13:48:37 EDT 2006 | dwelch123
I'm having trouble printing leads on a fine pitch part. The lead is only .008". I'm using a DEK 265 with metal squeegee and using WS200 multicore solder paste.The stencil is laser cut and polished. I've experimented with different pressures and diffe
Electronics Forum | Thu May 18 10:20:55 EDT 2006 | slthomas
Russ asks good questions and I think Chunks pretty much nailed it. Aspect ratio (aperture width/stencil thickness) s/b 1.2 minimum (I like 1.5 if I can get it). If your aperture width = lead width (.008"), yours is 1. Tough to get consistent paste r
Electronics Forum | Fri Oct 18 09:27:53 EDT 2013 | dontfeedphils
I believe it's mostly worn off through cleaning solvents and the slight abrasion during the under stencil cleaning process. I couldn't say whether or not it's ever in a state that would allow it to transfer to the PCB though.
Electronics Forum | Mon Oct 14 10:53:28 EDT 2013 | emeto
0.5 if you use electroformed stencil or > 0.8 if you use laser cut. 2. Always use fresh paste 3. Uses the right printer parameters for your paste(for example Alpha likes fast release of the stencil from the board - in DEK this is called separation s
Electronics Forum | Fri Oct 18 08:54:18 EDT 2013 | emeto
Hege, the Nano coating goes on the opposite of the squeegee side of the stencil. I don't know if the cleaning paper is able to remove it little by little with the time, but I never refreshed my stencils with Nano coating and they work just fine. How
Electronics Forum | Tue Oct 22 09:20:31 EDT 2013 | swag
Yes, car rims (and brass tubas)! You finally helped me get to the bottom of this expensive issue. We fired the culprit. It's the same guy that was using the ultrasonic stencil washer to clean car parts on night shift. It might be snake oil, I don
Electronics Forum | Thu Oct 28 11:50:11 EDT 2010 | phase1
We are having a little trouble with what appears to be a crystalization between our fine pitch parts. The problem appears after a a thourough wash of the pcb when dry. It looks like lead wiskers/haze between the joints.We are using water soluable lea
Electronics Forum | Thu Sep 07 10:45:46 EDT 2006 | vicknesh28
Yes solder is reflowing on the pad but doesnt wick up the lead. Solder paste is sufficient. It just forms a saddle like appearance beneath the failing lead. The failed lead doesnt get reflowed at all. What puzzles me is how can hundreds of leads wet
