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Author: rorschach
Time: 03/23/01 11:12 PST
This is a reply to message no. 6540 by descon
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Experiences in Eliminating fully detailed Engineering Drawings
I cannot comment on the paperless aspects of this question. But I can share my experiences with drawings that were not fully annotated.

Where I currently work, in the early days, all the drawings were created by the (founding) engineers, they had no drafters at all, and predictably, the drawings were crappy. Missing dimensions, geometry not to scale, unclear tolerances, etc. The machine shops who made the parts more often than not managed to make acceptable parts despite not having enough information to do so. They guessed, and usually guessed right, or they called, got the information, marked it on thier print, and hung on to the marked up print because they knew, we'd never get around to fixing the drawing.

The problem then became that they sometimes didn't use the updated prints when they did get them, they had gotten used to using old recyled prints... and they missed changes then. But when they didn't make a part that would work, the root cause more often than not devolved to bad data, and when that happened, we had to eat the bad part because the machine shop was just doing what they were told.... and when you consider the parts were made out of Inconel 718 and other exotic materials, you can guess how much that was costing us....

The problem got so bad that we were locked into the shops we had started out using, despite the fact they were now too small to handle the workload. Nobody else could figure out how to make the parts from just the print, there was too much "institutional memory" built into our vendor base.

We finally woke up to how much money we were loosing due to bad drawings about two and a half years ago (after about 4000 drawings had been generated!), the dollar figure was staggering... We still have a bunch of bad drawings floating around, even ones on our bread & butter products, but they are slowly but surely being redrawn, to scale, and dimensioned correctly to avoid these sorts of problems. When drawings are ECN'd they are gone through fairly thouroughly to fix these sorts of things... eventually the only drawings left will be inactive/obsolete ones... but it will take a while to get there.

My advice, if this is a "startup" group... It is easier to prevent this kind of debacle to begin with than it is to try and fix it after the fact. If they don't want fully defined drawings for thier parts, then I question thier sanity, because if you do not specify what you want, you deserve what you get!
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