Issue link: https://iconnect007.uberflip.com/i/1526114
SEPTEMBER 2024 I SMT007 MAGAZINE 9 ated an adhesive that "stuck lightly to surfaces but didn't bond tightly to them." Meanwhile, Silver's colleague, Art Fry, was frustrated that the paper scrap bookmarks he used to mark passages would oen fall out. Fry put his problem-looking-for-a-solution and Silver's solution-looking-for-a-problem together, and Post-It Notes™ was the result. Truthfully, quite a lot happens when creat- ing and applying solder paste. As components get smaller, the grit of the solder needs to get finer. Likewise, as BGAs and the like get larger, the solder ball gets smaller to make room for more contact points, requiring smaller solder grit. Even when our components get larger, the solder still gets finer. Where it gets complex, though, is that these divergent parts increas- ingly require different thicknesses of solder paste to bond properly. For stencils, this can be a particular challenge. Meanwhile, solder print technologies—pri- marily dispensing and jetting—are gaining acceptance. e tried-and-true method of sol- der stencils still works, of course. But print- head-based alternatives have made strides. If you've not looked at these pieces of equipment before, now might be the time to do so. It's not lost to me that legend printing, solder mask jet printing, and solder paste printing are all tech- nologies simultaneously on the rise. But changing solder paste, or solder paste application, can cause cascading changes down the line. Changes in the flux formulation can require changes in cleaning, reflow, and virtu- ally everything. Nolan Johnson is managing editor of SMT007 Magazine. Nolan brings 30 years of career experience focused almost entirely on electronics design and manufacturing. To contact Johnson, click here. So, for this issue, we get down to the nitty- gritty of solder paste. Ron Lasky and Adam Murling kick open the door with a discus- sion on current solder trends for printing, and Mike Konrad and Tony Lentz follow right behind with an overview of the technologies. Wolfgang Heinecke of Mycronic gets into the details of jetting, and Sunny Agarwal of Cama- lot Dispensers does the same for dispensing, and Josh Casper debuts in SMT007 Magazine with equipment insights. Neil Hubble and Gary Brist share their most recent research on the increasing importance of surface planarity to the soldering step. Finally, to cap it off this month, we include a paper from Dr. Prabjit (PJ) Singh (IBM, iNEMI) on the electromigration of bismuth in solder joints. Aer all the conversation in this issue on solder granularity, Singh's work shows what happens to the bismuth over time. Whether you're a front office executive, line supervisor, operator, engineer, customer service/sales, or an R&D expert, we've got information you can use on solder print in this month's issue. With luck, we'll have helped foster some creative responses to solder print technology for you. I know you'll enjoy it. SMT007