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What is the IPC Definition for Uncommonly Harsh?
Board Talk
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TranscriptPhil Welcome to Board Talk with Phil Zarrow and Jim Hall of ITM Consulting, the Assembly Brothers. Today we are coming to you from high atop Mount Rialto at the ITM elegante ballroom. Jim, what is our question today? Jim Well, interesting, it is about specs and regulations. It comes from S.M. What is the IPC definition of uncommonly harsh? IPC 610 and other documents define class three to include products where the end use environment may be uncommonly harsh. Does anyone have guidelines for how uncommonly harsh may be defined.
Boy, this is interesting a question about harshness coming from a guy whose initial are S&M. Getting to S&M's question, uncommonly harsh. To the best of our collective knowledge, which you could probably fit in a coffee cup, I do not believe that 610 calls out an actually definition of harsh. Now understand that other generalized specs in other portions or corners of the industry such as automotive, other industrial applications like downhole drilling things like that, they probably do have sets that define harsh or define the environment. But looking at the general term uncommonly harsh, and looking at the items that you mentioned. Well, let's take a look at it, Jim. Temperature ranges and ramp rates potential for being uncommonly harsh. I don't think so, not with regard to 610 the actual joint. It might deal with flux residue. There you might get into something. But that's not what 610 is about. We're talking about joint integrity. So I don't think that a temperature range or ramp rate, thermal cycling would definitely have an affect. And again, what it is going through there. But I don't think an actual range that way. Jim, what do you think? Jim Well, as you said if it is subject to thermal cycling. Basically 610 is defining the physical structure of the joint, what it looks like, how big the fillets are and so forth. The biggest impact that it is defining is mechanical stress. Thermal cycling is a big source of temperature stress. So yes, temperature range could be indirectly creating stresses which might be considered uncommonly harsh. The other thing that jumps out at me, Phil, is vibration levels. Yes, many of the specs that you talk about, military, automotive and so forth, define very specific levels of vibration and other shock mechanical stresses that they test too. I think that goes back to the idea of IPC specs. They are the starting point from which you base your specific needs for your specific product and its specific environment. What is uncommonly harsh may be different for different products. Phil There is a limit to how generic specifications can be. And we have discussed this many, many times. You can't look to them basically as Holy Scripture all of the time. You have to look at your own application and conditions, certainly your manufacturing situations, and things like that. So yeah, I totally agree with my brother here on this. Be very, very careful. You have to really examine, the application is what really defines it. You can't always keep a generic definition. Jim The other bullet point is sunlight uncommonly harsh. Not relative to a 610 solder joint evaluation. But other IPC specs that talk about solder masks maybe that might relate there, or a moisture, humidity and chemical type. Once again if we are talking about some of the IPC specs that relate to printed circuit board fabrication and its materials, those factors might be considered uncommonly harsh relative to the materials once again of laminates, coatings and so forth. Phil Very good. I think we covered it. Hopefully gave some direction on that one. We are here to help. We try. You have been listening to Board Talk, Phil and Jim. Whatever you do, whatever kind of environment you are using your application in... Jim Don't solder like my brother. Phil And don't solder like my brother. |
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