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APRIL 2018 I FLEX007 MAGAZINE 37 so that's all the Class 2 products. Class 3 stuff is the military, avionics, aerospace, implant- able. That's all going to stay in the United States. In automotive you're going to have shock and vibration, you're going to have extreme temperatures, both high and low, things like that where you wouldn't see that in a cell phone. Cellphone is going to be experienc - ing pretty much room temperature and unless you drop it there's not going to be any shock and vibration. It's a completely different ani- mal between those two. Another thing for automotive is cost. They are trying to shave off everything they can, whereas in high-end commercial they've got a little bit more space because they're providing a premium product and people are willing to pay for the newest electronic widget out there. When you start getting pressed for cost, then you start looking at less expensive materials that can affect the end performance, which you're trying to keep up on the top end also. Matties: So, the strategy for cost is really important. Weldon: That's a good point about the require- ments, because the requirements are different, but there are even standards that are differ- ent, right? So automotive might use IEC. A guy who uses software might use IPC. With auto- motive, you don't have to have UL. There are certain things that are very different. If you're new to automotive, making flex, this is what you need to know. Build according to these specs or these specs. These are things you need to be worried about. These are things you don't need to be worried about. I really like that point, thank you. Matties: When we look at design, I know we talked about PCB designers, but how involved is the system designer in this process? How much influence do they have over the actual parameters? Finstad: Seems like really often the flex is the last thing that gets designed into the system. They get everything else put together but now they've got to hook it up and make a bunch of flex to do it. You end up trying to work with the available space that's left over after every - body else got their portion of the volume. Matties: We hear frequently that things are just thrown over the wall and you have to hammer it in. Freedom CAD probably knows that the best, correct? McCurdy: We see that same thing. It's pretty accurate. I think, too, what we see at times is the use of flex for power applications, and that's probably something that has its own uniqueness because it's done for different reasons but having copper poses a different problem. Finstad: I agree with that. We've looked at replacing a lot of wire harness and cable in automotive with flex and cost is the primary issue but even getting down to what thickness of copper do you use to replace those high current power lines. You're talking 12 volts and 20 amps. That's a big copper trace. And with a cable that's braided it's not much of an issue, but you try to turn that into a flex circuit, what do I do? Do I use two ounces of copper that's three inches wide? What the heck do I run here and then how do I build a circuit around it and make that even remotely cost effective? It gets even more interesting when they say, "Let's run a couple of differ - ential lines right next to it." And, of course, they say that every time. Matties: I think we're pretty close to wrapping up. Andy, is there anything else that we need today? Shaughnessy: I think we covered it. Thank you all for your time. McCurdy: Thanks, everyone. FLEX007

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