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SMT007-Jun2023

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56 SMT007 MAGAZINE I JUNE 2023 It's interesting because it shows the difference in dynamics between batch and inline clean- ers. Batch systems, for the most part, are very self-contained—they wash, rinse, and dry in the same chamber—but they don't turn on the exhaust until they're doing the drying. ose tend to be much more stable. ey don't dri much, and it's a very gradual change over days. Inline systems have air knives at the end of the wash section to "scrape off " the clean- ing material for continued use. at's a value- adder and good for the customer. But now I'm pumping in a few hundred CFM of air with that air knife. What goes in must come out. It would compromise drying if all that moist air were to come out the drying end. Of course, we don't want a cloud of exhaust coming out the input end either. So, the inline system wash chamber dynam- ics of the spray action is somewhere between 40 and 100 PSI (actually doing the washing), and proper exhaust to bal- ance out that air knife input gets you a very dynamic environment. You can be out of your desired constraints in less than an hour. ose automated control systems are worth their weight in gold. More importantly, beyond the substantial chemical savings, you get a rock-solid process. If you're supposed to be at 10% or 12%, you're at 10, not at 11% or 14%; and the corrections are small, not large, gross adjustments. It's kind of like driving your car down a straight highway, lightly touching the steering wheel as you move it back and forth a little bit. e adjustments are quite modest, but it's a big part of reduced consumption and a better process that delivers quality opera- tions. What trends do you see? Are people look- ing for the inline or batch process, or is it still application specific? It tends to be driven by the tempo in the indi- vidual shops. What percentage of your pro- duction requires cleaning? is is not about using no-clean technology, but whether your clients require their assemblies to be cleaned. It is worth remembering that no-clean is actu- ally the only modern technology. Barry, what is your guess about how much R&D money has gone into a solder paste that's not named no- clean in this century? I'm guessing it's a fairly small number. Ev e r y o n e , w h e t h e r they clean or not, uses no-cleans because sol- d e r te c h n o l o g y h a s improved this cen- tury. It performs better and has a better user experience due to the great features the sol- der de velo p er s have invented and brought to market. But it's a case of who chooses to clean and how much of their production requires cleaning. For example, the aerospace segment never really stopped cleaning but isn't known as a high-volume crowd. ey tend to be more batch oriented. Medical devices are changing. Many have gone mass market, such as diabetes implants and other devices employ- ing all kinds of sensors. ose are more oen high volume and inline-oriented, but they can still be cleaned in batch systems. e military tends to like inlines, but they also use many batch cleaners. It's really a function of what you do. Con- tract manufacturers oen use inlines because, of course, they're about bundling business together to gain volume efficiencies. It's not Those automated control systems are worth their weight in gold.

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