The entire title suggests it should be in the CAD/CAM forum but the question I have doesn't really relate to any particular software, so here goes.
Suppose you model a part, which is part of an assembly that may not physically change. As your machining the parts, it is determined additional material removal is required for a better fit, therefore you make a change to your CAM program. Do you then go back and make your model match what would be the output from the machining operation, then redo your CAM programming, for future use? Or just leave everything as is and change if an actual modification is called for down the road?
I'm still trying to nail down the exact meaning of what you are driving at here ?
My interpretation of what you wrote is kinda like this.
Jay writes:
"Suppose you model a part, which is part of an assembly that may not physically change. As your machining the parts, it is determined additional material removal is required for a better fit, therefore you make a change to your CAM program"
Apologies for length, (just wanted to nail down the situation... / bugging me/ knowing away at me lol).
My interpretation of what you wrote is:
1. You can't change the model for the part (that needs adjusting) because it's part of a CAD assembly representation. I.e. the part you are cutting in "computer/math space/CAD" directly fits with adjoins abuts or is fitted to other parts as a sub component in a larger CAD representation of potentially 9 or more other parts? [Well two or more at least]. So if you change the dimensions on one part then therefore one would have to change the dimensions and tolerances on all the other contacting components?
OR are you saying it doesn't matter cuz the final dimensions are smaller / were oversized, just remove more material on the one part so it won't affect the other parts in the assembly (kind of thing?)
2. It sounds like the issue you may be having might stem from CAD errors of representation VS set up and machining errors... VS. hard coded CAM won't have CAD translation/geometric errors?
3. It's not clear if the changes you are having to make are from Errors in CAD, natural errors that might happen if you are trying to achieve really close or difficult to achieve tolerances? Without knowing the tolerances or reason or source of change / error it's hard to make an explicit call here, although I obviously agree with everything said so far.
4. Are the changes to make the thing "Work" just plane old design errors?
Maybe I'm way over thinking this but from the wording of your post ^^^ These things came immediately to mind.
The question you pose is interesting to me as most machinists seem to focus on absolutely busting their arse to deliver on that one component or part in the best way they can. But
@Jay Fleming what your question poses here is more about how a machinist (perhaps in a prototype environment) might be responsible for multiple parts working together...
That's very different. Kinda crosses the line between machinist and project engineer IMO.
[Mild anecdote: As a more naeive designer 25 years ago (still kinda wet behind the ears) I gave out institution's head machinist a very well executed assembly drawing, and he looked at me as if this was a major insult and I had given him a steaming turd. So he had to explain that he could ONLY work off single part drawings/CAD drawings etc. We became (eventually became) BFFs... But still underscores the incredible focus that a lot of machinist's have for the ONE part and I have to be honest that
most designer's think in terms of assemblies and systems of parts working together].
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Long story short: scratching my head seems like you have to attach or maintain the physical changes as a separate step (interim working attached annotated document) before things go back up stream so that the designers or engineers can decide how things need to be altered. If its really close/difficult tolerance stuff that is causing problems between CAD representations and physically cut surfaces
it could take Three or more iterations for the CAD model and final machined surfaces to converge with each other YKWIM? Not to get super bureaucratic about it all but kinda depends on what the organization is and what procedures either constructive or
obstructive that may exist to iron out all those kind of wrinkles.