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Can anyone provide some pro's and cons of switching from .0012 relative part accuracy to .0005 absolute accuracy? Experiences with the effects of doing so on merges, cut outs, assemblies, manufacturing models,and any other potentially troublesomeeffects would be great!
Fame and fortune awaits the most compelling response.
Thanks,
R.Swenson
Here's a link to a good discussion on the subject:
http://groups.google.com/group/comp.cad.pro-engineer/browse_thread/thread/7ac7b385bb720124?hl=en&q=jeff+howard+%22accuracy%22
In Reply to Christopher Gosnell:
Where do I start...
All of the tasks you list are affected. For example, we design parts
that are approx 1"x1"x1" to 8"x8"x16" for medical and aerospace
customers, and we set our accuracy to .0001 Absolute when working in
inch units in Wildfire 4 M040.
As far as I can tell, the only reason for playing with the accuracy was
to balance regen time against part 'fidelity'. As you can imagine with
such a large range in part envelopes, we were getting different results
for mold making, feature creation, even machining tool paths when the
part accuracy was set to .0012 relative. Machining 'accuracy' is
another, related issue as well, as is set to .0001 absolute.
Secondly, we do not use 'merge' and 'cutout' for making mold cavities
because these are 'solid' features and will either: 1) fail to complete
the feature, complaining about different accuracies, or 2) Try to
'match' the part accuracies when in TDO (Tool Design Option).
We use Insert | Shared Data | Copy Geometry... in part mode to do mold
cavities, etc. This is because the feature is a surface, and as AFAIK
seems to be 'immune' to the mismatched accuracy gotcha. To cutout the
cavity using the Copy Geometry... feature, select the quilt and Edit |
Solidify... in part mode. Now you have created an external
dependency when doing this, the implications with regards to Interlink,
et.al... I cannot comment on, we don't use it.
Now to do the copy geometry function, you need to make sure that you
have the proper licenses, options and extensions. We have been a long
time user of Pro-E and as such our old licenses rolled over to
'Foundation Advantage' licenses. Because of this, we need TDO, Pro
Assembly (NOT Pro-Assembly-Performance), or Pro Manufacturing floating
options enabled before we have the Copy Geometry... command available.
Again, AFAIK, 'regular' Foundation licenses do not have this limitation.
If you would like more detailed examples, and/or test cases, maybe I can
help...
Christopher Gosnell
TRIGON INC.
FPD Company
124 Hidden Valley Road
McMurray, PA 15317
Here are the responses I received regarding relative vs. absolute part accuracy, names removed to protect the innocent. Thanks to everybody for the valuable feedback!
In general you should experience better results once your parts are maintained at a consistent absolute accuracy. Now the value of the accuracy is dependent on your units and the typical size of your products. For example, I typically run at .01mm and .004in. However, if your products are relatively small (heart defib) you may want to run it slightly tighter .005mm as an example.---------------------------------------------------------------------------------------------
I assume your question applies to starting a new part with absolute accuracy vs. converting an exist relative accuracy part to absolute accuracy.