Issue link: https://iconnect007.uberflip.com/i/1389320
JULY 2021 I SMT007 MAGAZINE 17 ere's no shortage of cleaning chemistries or equipment. It's a matter of experienced operators and engineers setting up the wash profiles to give themselves the best chance to do the best job possible with that chosen set of materials. I just got back from a customer site, verifying two wash processes; you just make a couple little tweaks on these things, and it can have a huge impact on cleanliness. Whether you're building a true no-clean pro- cess, or you're washing it off, it's just knowing how to get to that cleanliness point. Johnson: How does someone get the expertise needed to get clean boards? Camden: e same way my kid learned to ride a bike; you just keep doing it. I mean, you fall off, you hurt yourself, and yet you keep going. If you're lucky enough, you've got a mentor within your facility there. Short of that, there is an abundance of online articles and videos on how to clean a board, and you can join groups like SMTA and IPC. A lot of people get this experience aer they've done it really wrong, and it can be fairly expensive; that's trial by fire right there. ere are a lot of different ways to do it depending on how much effort they want to put into it. Johnson: What does an assembler really need to know right now to make reliability better? Camden: ey need to know that cleanliness and the entire assembly process is important. ey need to know that the quality depart- ment is something they should never short- change on. To know how clean your boards need to be at the very last spot before they're shipped out, you need to know how to mea- sure and monitor how clean that board is, and you've got to know how to do all your home- work. Like I said, the J standard, the WP-019, is a very good reference for what they need to know to set their cleanliness criteria for their own products. at's the thing they've needed to know all along. Nobody knows your board like you do, so you need to be doing your own cleanliness testing. I've never been an advocate for a one-size- fits-all. Even as I sit here at a failure analy- sis lab, we have our own recommended limits that work for most of our customers, but never would I ever say these numbers will absolutely work for your board. We say, "is should work for you, but you've got to do some testing to determine if it will or will not work." Every CM has come to that conclusion, and now they're trying to determine how best to get to it and follow the new IPC guidelines. Contract manufacturers don't follow IPC standards out of the goodness of their heart; the standards are called out in a contract somewhere. e big CMs certainly work with IPC, but they only follow these guidelines because they're asked to by their customers. Johnson: Do you expect to see reliability in the assemblers' environment change over the next three to five years? What's over the horizon? Camden: I see better in-house testing capabili- ties for testing live product. I think companies will go to more testing right aer manufactur- ing, and they will test larger lots in an environ- mental chamber to really put some moisture onto their boards that determines what the quality and reliability is. I think there will be a better eye on how to qualify live product and not just test boards. Contract manufacturers don't follow IPC standards out of the goodness of their heart; the standards are called out in a contract somewhere.