Electronics Forum | Wed Dec 19 15:23:32 EST 2007 | arun2382
Hi, How do single pass and double pass stencil printing compare? Is one preferred to the other? Any risks associated with double pass stencil printing? thanks in advance -Arun
Electronics Forum | Thu Dec 20 12:48:03 EST 2007 | arun2382
Thanks for all your comments....my question is answered!
Electronics Forum | Wed Dec 19 16:53:41 EST 2007 | flipit
Double pass printing for solder paste is not needed and will cause defects. Redesign your stencil thickness or aperture sizes, change your paste mesh size or type, go to 45 degree blades.
Electronics Forum | Wed Dec 19 22:39:03 EST 2007 | davef
Search the fine SMTnet Archives for previous discussion, like: http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=48507
Electronics Forum | Thu Dec 20 13:29:27 EST 2007 | slthomas
Ahhhh. Sorry. It's been a crap week and I've got a touch of hair trigger fever. Somebody pour me a Scotch. It's noon somewhere.
Electronics Forum | Thu Dec 20 12:05:46 EST 2007 | realchunks
Not you Steven. Blanket comments like "Double pass printing for solder paste is not needed and will cause defects. Redesign your stencil thickness or aperture sizes, change your paste mesh size or type, go to 45 degree blades." are so way off base.
Electronics Forum | Thu Dec 20 07:50:12 EST 2007 | realchunks
Good to know there are a few smart people left in this industry like Darby. I love how everyone assumes the original poster was only talking solder paste. We use screen printers for five different materials. Some of which we triple print by design
Electronics Forum | Thu Dec 20 08:00:50 EST 2007 | avalancher
Many years ago, we used to double print. The way we did it was with a rubber squeegee set to do a flood stroke, followed by a return cleaning stroke with a metal squeegee. Why?! Well, this was in the days before Laser etch, and because the chem bat
Electronics Forum | Thu Dec 20 10:15:09 EST 2007 | slthomas
Wow, Chunks, condescension becomes you. Not. I think that in this forum when someone mentions *stencil* printing and doesn't specify what material, we tend to gravitate towards a scenario that involves printing solder paste first, then adhesive. If
Electronics Forum | Wed Dec 19 15:32:03 EST 2007 | slthomas
"Any risks associated with double pass stencil printing?" Mostly just too much paste, plus the associated bridging, and your stencil gets dirty quickly. Any gap between the stencil and the board gets filled with paste on the first pass, then migrate
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