Issue link: https://iconnect007.uberflip.com/i/1367446
MAY 2021 I SMT007 MAGAZINE 69 ere's a lot of aspects to what happens through the wave. How long each section of the board is going through the wave—and get- ting that good solder joint—is directly corre- lated to the dwell time. Johnson: Not to sound like an old timer, but back in the day this was generally a static pro- cess, the sort of thing that you would need time to set up. You would have to run through test boards, figure out what the appropriate set- tings were for all of the conditions through the three stages, do a thorough profile, inspect the test boards, and refine the process until that one particular board was dialed in. en, you stuck with those settings, and you had to check the finished product regularly; it was a static process. With the move to factory automation as a general trend, is the WPI doing real-time checking? Moreau: Effectively that's what it's like, it's like running that fixture check through for every production board. e challenge on the wave is doing static vs. dynamic, or more real time. In a reflow oven you are managing based on the control of the zone and what external forces can impact the profile or how it changes. With the solder pot, it's extremely dynamic and somewhat unpredictable, even if you fine tune all of the mechanical settings and manage the height, how you're collecting off the dross, the pump, the temperature of the solder. It's very dynamic so the more frequently you can do that check during production, then you're going to reduce the opportunities for defects. Now what you do is, why not take that to continuous? Let's do that for every sin- gle production board, so that if there is some change, we can put a tolerance around what's acceptable. en if it goes beyond that, we can alarm and prevent other boards from going through when the setup is no longer good. Johnson: at used to be a tactic, right? Espe- cially in wave solder, you would create a toler- ance window, and it would be pretty large, and you would have to make sure that you stayed within that window. Does this give you the opportunity to tighten the tolerance windows? And what is the benefit there to the customer or the OEM? Moreau: Like you described before, you do all these tests, you run profile aer profile, and then you come up with the tolerances, but that's just based on these static measurements. Now imagine I can run for two hours and get the data that took me two to three days to col- lect before. en I make the necessary adjust- ments and can have continuous improvement on the fly, with real-time feedback from WPI. No more time-consuming manual processes; you're getting the real-time feedback so then you can tweak your tolerances as you go start to improve the process and really tighten it down. It not only gives you the value of, yes, I'm getting this data to make sure that my cus- tomers' product is being built correctly, but I have real-time feedback now where I can actu- ally fine tune and improve this process. Johnson: Does being able to fine tune and get more precise benefit the OEM? Moreau: Yes, they have the assurance that the product being built is in a much better con- trolled process, so it's going to reduce the defects, the quality is going to improve, and then you have the traceability. ey have the information that, "Here's what happened in the wave;" not saying at the beginning of the shi, "I checked the machine, and everything was okay," but, "As every one of my boards went through, I know what happened." Johnson: Right, and there's a value there as well, isn't there? Moreau: Yes, and that gives them full trace- ability.