Gene Heskett wrote: > Could one use the resultant laser cut stencil as if it was a silk screen to > apply the solder paste? > That's the idea. > If so, that would certainly cut large hunks of time out of the process once > the stencil was made. However, having the paste exposed to the air while > on the stencil would make me want to figure out a way to flood the area > with GN2 to slow the oxidation that would occur while doing the time > consuming pick-n-place, and on to the reflow oven. No, this is NOT necessary with modern solder pastes. You can leave the paste exposed for hours, and the only problem is the bulk paste dries out. You add a few drops of butanol to get it liquid again.
Some outfits do use nitrogen purge in the ovens, but you need a LN2 dewar for a big oven. Nobody uses special atmospheres for the P&P machine. That would be wildly impractical. Jon ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
