Issue link: https://iconnect007.uberflip.com/i/1243344
80 SMT007 MAGAZINE I MAY 2020 share something now that's my opinion; BOFA hasn't taken a position one way or the other on this, so I want to say it as my opinion and not BOFA's. My background is in the solder- ing industry. I was in that for a long time, and I have always heard people talk about they're worried about the fumes containing some metal. All of the studies I ever had seen con- clude that isn't the case. The fumes are the flux. There's potential, theoretically, that some molecule of the solder could grab on to that flux particle that's being vaporized and you'd get a little bit of that. I haven't seen a study that said that's happening. All of that's to say that the size of the sphere of solder that's used in a solder ball I don't see it having much of an effect on what we're picking up. What has a much greater effect is all of the changes in the chemistry and the types of fluxes. Going to the no-clean flux, you have a lot smaller percentage of solids in that, which are what end up in a lot of that vapor that's caused by it. Because we're going to lead- free solders, they melt at a little higher tem- perature, and industry has kind of typically then said, "Everything needs to be done hot- ter," which then causes a little bit more vapor- ization of that flux material. Or in a lot of hand soldering applications, you get people adding liquid flux to their flux-cored solder that kind of starts counteracting the no-clean that they were using. If you throw enough no- clean flux on something, you're going to need to clean it. Johnson: Does that increase the filtration need, and do you have to go to different filters or move more cubic feet per minute? Mitchell: It would still be the same types of fil- ters. I would not say that it requires additional airflow, it doesn't require a different filter set. It requires the attention to creating that cap- ture area. Johnson: When you go into a customer facil- ity to talk to them about fume capture, how often do you find that the facility is adequately arranged? As far as the physics of setting up smaller solder ball sizes are appearing in some mixtures. Do these changes play a part in what kind of products you need to deliver to elec- tronics manufacturers? Mitchell: I would say in the bigger picture, if I'm hand soldering with lead-free solder or tin-lead solder, how I capture it is pretty much going to be the same. That lead-free solder probably has a no-clean flux on it with low solids, so it's putting out fewer particulates than the old tin-lead solder with 30% solids RMA flux, but I'm still going to capture that the same way. As things get smaller, in one small respect, you could say it makes it a little bit easier because you don't have to try to cover as wide an area. Parts are getting smaller and the boards are not significantly shrinking unless the end-product is a small product like a cellphone or some- thing like that. Johnson: It's the size of the grit that's used in the solder. Mitchell: That doesn't affect what fumes and particulates come off of that. I'm going to AD 1000 iQ laser fume extraction system shown with access door open.