Issue link: https://iconnect007.uberflip.com/i/1379105
14 SMT007 MAGAZINE I JUNE 2021 Forsythe: Not exclusively, but mostly these days. Johnson: en we have processes and technol- ogy referred to as "no-clean," which you can leave in place. Forsythe: Some people can leave it in place. Johnson: Some of the reliability labs share that cleaning no-clean is oen the cause of reli- ability problems, by exposing materials that weren't supposed to be exposed. Forsythe: Right. It turns out that doing things badly mostly leads to bad outcomes. For exam- ple, why don't they just leave the no-clean on pacemakers? It's a tough question. Life is in the balance. Now, the soldering people view that example as a vast outlier, but you know what? If you're flying to the International Space Sta- tion, what's your perception of reliability? What about driving an electric car with batter- ies that you don't want to catch fire? I'm not so sure they're very different. e idea that no-clean—le to its own devices is appropriate for every application under the sun—is a concept worthy of a lit- tle scrutiny. e world agrees with us, other- wise we wouldn't be in business. A few water solu bles are the exception to that, but even they're experiencing a lot of issues these days. ey had their day, shall we say, on average. Just like wave solder, nothing ever really dies in the electron- ics industry. I ask all the solder guys, "How much R&D have you put into something people are going to clean?" ey reply, "About zero." If I know I need to clean something, and I'm on that spaceship or need that pacemaker, would I want to use something that's 30 years old? Why would that be attrac- tive? What else do we use that's 30 years old? It's a short list. Johnson: en there are the situational con- cerns with the components that you are clean- ing around. Forsythe: Cleaning is like dating—when it's going well, there's touching. If the cleaner can't touch the soil, it has no chance of removing it. If the cleaner can't touch it with some mechanical energy, it has less chance of removing it. It has some chance, but it's less. If the cleaner can't get there with some temperature, which for most substrates turns out to be the easiest one to make happen, likewise, that makes it harder. Just like when you're doing your dishes at home, try it with cold water and try it with hot water. It's a little easier with the second technique. Because of decreasing standoffs and verti- cal gaps underneath devices, not to mention flush-mounted components, and the general density of things, cleaning absolutely contin- ues to be challenging. Solder people have put most of their R&D investment into no-cleans. Likewise, we in the cleaning world have spent tons of money on R&D trying to make sure we can remove those doggone things. We can and do have data. It all works. However, if you do it poorly, it doesn't work well. Johnson: Right, which then manifests as increased reliability issues. KYZEN's labs are equipped with the latest analytical equipment and staffed with a team of highly trained chemists to provide support to customers worldwide.