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Enough Blame to Go Around
September 4, 2017 | Scott Decker, CID+, UTC Aerospace SystemsEstimated reading time: 2 minutes
The idea for this article began a few months ago when The PCB Design Magazine conducted a reader survey regarding the topic “Whose Fault is that Bad Board?” After some thought, I submitted my answers. After all, I must have some kind of input after over 25 years of PCB design. But still, whose fault is that bad board?
Most of a PCB designer’s job involves placing parts and routing traces on a CAD tool, and then whipping out a set of drawings and Gerber files to send to the fab shop. Some of you even draw the schematics and maybe even do some library work now and then. For me, I’ve done all of that and more over the course of my career. That doesn’t make me a great designer; it just says I’ve done a lot of different things, as I’m sure many of you have too. So when it comes to problems with PCBs, just who is really at fault, and what do you do about it when you have issues, big or small?
As designers, we are typically detail-oriented and most likely perfectionists when it comes to our design work. I’ll admit it: I could clean up routing for days, but I limit myself to an hour or so per layer, as hard as that is for me sometimes. Unless it’s in-our-face obvious, when we try to decipher what happened when we have issues with a board, we tend to look someplace else.
OK, I know what you’re thinking: Don’t go there. We designers make mistakes too. Some of the things I’ve learned along the way came from making mistakes, and as we all know, that’s how you learn. As an example, and I have lots to choose from, once in my early days of design, the drawing checker asked if I could remove the leading zeros from dimensions under one inch. I thought about it. I really didn’t want to do this, because the zeroes are interactive with things on the board. His reply was that if I could possibly do so, then take the leading zeroes off any dimensions under one inch.
Against my better judgement, I did it anyway, and not more than a couple of weeks later, I get a call from the fab shop. It seems they started routing into one of the boards in a six-up panel. After I did a little investigating, I remembered that I changed the frame outline a bit and, you guessed it, the dimension didn’t update. Once I got the panel from the shop, I proudly took it up to the checker and exclaimed, “See, this is what happens when you override a dimension!” His answer was, “I just said to remove them if you could, not that you had to.” So, whose fault was that? His for requesting that I remove them, mine for doing it when I knew I shouldn’t, or me for not remembering I did it or maybe not providing a compelling reason not to? After that, I had a good reason for leaving the leading zeroes alone, no matter what the dimensions are. Lesson learned.
To read this entire article, which appeared in the August 2017 issue of The PCB Design Magazine, click here.
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