Flag note inside the DRF

[[Ia...]]

Hey guys,

I've never seen this before.

Flag note 3 states: Contour, Trim, and hole locations per : "CAD model file"

This is for all profiles and position call outs. There are no basic dimensions, only reference dimensions.

I'm at a loss on how to measure this with a CMM.

[[SH...]]

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I have seen in my drawing something like this in notes ,not inside a feature control frame. which is specifies that true position is this much unless otherwise specified. This May not be correct , I think you have to use co ordinate in the cad model without any transformation and rotation.

[[Ca...]]

Do you have a CAD model? VERY preferably a customer supplied one? I've never seen a flag note inside an FCF, but this reminds me of some of the lite drawings we have. Those prints have almost no real dimensions on them, and typically have a non-flag note similar to what you described. They aren't inspectable without CAD model support.

Something like: A 3D model and this print are required to inspect this part. Unless otherwise specified, all surfaces to be within .010 true profile when banked on the datums.

[[Ia...]]

I have the model.

Do I treat the positions and characteristics like they aren't referencing datums?

Or

Do I have to make some sort of best fit alignment that contains every aspect of the part?

There aren't any datums specified on the drawing.

[[Da...]]

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Disaster. What you can do is to get as much as information you can about how this part will function and decide and document the datums based on that.

[[Ca...]]

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I've never seen or heard of anything like this. I'd work with your engineering department, and like Dane said, start trying to understand the design intent to the drawing, and go from there.

GOOD LUCK!

[[Ia...]]

Just got an Email back, after asking a thousand questions.

"The trim and contour tolerances are defined, but the data defines the nominal, as designed condition. The dimensions are reference, and the print instructs you to refrence the CAD file for the nominal contours and trims."

I hate this job sometimes.

[[SH...]]

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I think ,this is the beginning of new Era, I love working with CAD models...

[[Jo...]]

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No, that's laziness on engineer's end. Short of laser scan, how to you evaluate profile on ALL of part ? Half the time the 2d views are generated from model and are lacking in information. It is a weekly occurrence where I have to pull a model and give enough information to machine shop to manufacture part. Info missing from drawing.

When I asked our last engineer what to measure, his response was "everything". REALLY ?

[[SH...]]

Maybe that drawing lacking of data,but l strongly believe after ten or twenty years there will be no 2D drawing.

[[Ia...]]

So is there a way to make a "best fit" alignment for the entire CAD model? I know I've seen 3D scanners in polyworks do something similar, but I've never seen it done in Calypso. Maybe using point cloud?

Or could I make a freeform surface that captures everything, and just use that feature to constrain all degrees of freedom?

[[Mi...]]

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Resources -> Utilities -> Geometry Best Fit

This lets you recall most types of features (not sure about 2D and 3D curves) and do a LSQ fit to them. It can take a while to compute for large numbers of features.

[[Ro...]]

Lazy engineering!
When you have a first year designer and a manager who signs off on everything.....

But its to your advantage, you can pick your datums and make them as simple as you wish.
if your exterior surfaces are suspect then find a reamed hole and use that as your datum, pick something that's machined together in the same workholding and offset group and make that your datum.
Whatever makes sense to you.
Just make sure to offer your customer a copy of your program (which they may decline, especially if they don't have a Zeiss of their own) so they cant get upset with your selections.

If your engineers are using the same cad model to program the CNC mills then that's the best because you don't have to deal with someone drawing a model with a nominal of X then changing the number by .010 thou and not updating the model.