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What Rate is World Class for SMT Machines?Board Talk
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TranscriptPhil Welcome to Board Talk. This is Phil Zarrow with Jim Hall. We are the Assembly Brothers, Pick and Place. And we're here to talk about SMT processes and materials, equipment. Jim We're going to have to figure out pretty quick, because this question is about pick performance, it's not pick and place performance. And it comes from R.W. The question is "What rate (in percentage) is considered world class when it comes to pick performance for SMT placement machines? Also, can you define pick performance? Phil I've got to tell you, in the world specifications, I don't know that I've ever seen it broken that way. And going back to your and my respective pick and place days, we used to do things like cycle time, and we say the pick from the same place. I think in terms of performance, you think old R.W. was alluding to accuracy as opposed to speed, but the actual accuracy, and picking the component out of its respective pocket? Jim We're only concerned about the performance of the machine in picking parts out of the pockets of tapes and feeders. And thus the percentage, so what percentage are you successful when you go to pick up a part? And why is this now becoming a question and not one that was asked 30 years or 40 years ago when you and I were working with the prehistoric placement machines? Phil Let's see if I can answer that. 1. We don't have enough specs to worry about, and the salesmen need something else to talk about. 2. R.W. is dropping a lot of components. 3. R.W. is not getting components out of his feeders. Jim I'm guessing, Phil, that the reason is that R.W. is having to deal with very small components - 0201s, maybe01005s. Having worked with 01005s, you know that picking them up becomes a big issue, because they're so small. Phil Seeing them then becomes an issue, let alone picking them up. Plus we all know the other issues attributed to picking them up, getting good release from the pick-up tooling. Jim Yes, but this is confusing. I'm shooting from the hip here, ladies and gentlemen, because pick performance can be affected by the machine. It can also be affected by the accuracy of the part within the pocket of the tape. And again, if we're talking about these real small chips, you can get bill boarding flipped upside down parts. If the machine fails to pick it up because it's bill boarded in the pocket before it even attempted to pick it up, is that the machine's fault? Is that be included in the percentage of failures? Phil My brother's made a very, very good point. It doesn't all aim down to the equipment itself. We're equipment guys, and we always had a bone to pick with component guys. How good is the actual tape and the stuff, the way it's being fed? But to answer the question directly, I don't know of any metric per se. Certainly, you suggested some good ones, Jim, but I don't know of anybody - we're probably giving the Pick and Place guys some really "Hot damn, here's a new one we can out spec 'em on." We know how that works. Jim I don't know. I just know that I've seen it in many people - have talked about the issues about picking these really small parts with perchance the need to use vision to find the part before you pick it up in some extreme cases. What are world class? I honestly do not know. I would assume you'd have to rate it for a given size and style of part. I know a 0201 or an 01005 - I would assume that your success rate, if we say it's the success rate of the pick-up tools to be able to pick parts up from a feeder pocket, then I would assume it would be lower for an 01005, because it's simply harder. You're bound to get more mistakes. But in terms of world class, I don't have any numbers. Phil But I'll tell you what, putting on my six sigma curmudgeon hat here, this is definitely an opportunity for a specmanship on the part of the Pick and Place guys. Jim And everybody understands the difference between placement accuracy at three sigma and placement accuracy at four sigma. We will not go there today. We won't go there. Phil We'll save that for another time. Until that time, this is Phil Zarrow and Jim Hall, Pick and Place. Jim Whatever you do, whether you're picking placing or handling both hats, don't solder like my brother. Phil Don't solder like my brother. |
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