Drawing vs 3D CAD Model 1

[Twullf]

I have a model that will have to be cast, but it has some very complex shapes. Using Unigraphics, I am unable to get a radius into a region I KNOW they are going to need it, the program just will not put the radius into it.

So here's my question. The Model will be sent to the customer along with a drawing. If I call out a larger radius on the drawing than they find on the 3D part, will that supersede the model? Or should a notation be included on the drawing to indicate that the larger radius is prefered regardless of what the model shows.

Unfortunately due to the complex geometry of the part the Model has to be provided as well as the drawing.

Thank you for your time,

 

[TWJR]

CAD does not define the part, the purchase order does, by specifying whether drawing or CAD file takes precedence. At least, that's what the lawyers say.

I agree that the model "should" be identical to the drawing, but here we always put a disclaimer on purchase orders stating that the drawing is the criteria for acceptance. The model may be provided, but is reference only.

 

[TheTick]

...we always put a disclaimer on purchase orders stating that the drawing is the criteria for acceptance.

Always wise, but that won't stop the manufacturer from carving away blindly from the CAD. If you can't reconcile CAD and drawing, best to be material-safe on the CAD model.

I've wrestled with stubborn fillets on-and-off for half my life (as many of us have). There is most certainly a brute force solution to getting a fillet in there, even if it means carving the solid up into surfaces and stitching back together. (UG/NX is particularly good for this.)

Also, it is not always the best course to use the design CAD model as the model to be used by the manufacturer. You may want to make a second model specifically for manufacturing. I usually do this and hand them a lobotomized, featureless model so they don't need to wrestle with feature regeneration time, etc.

 

[TheTick]

Again, take a long hard look at the surfaces being filleted and the features generating them. There's probably something to fix. If there are imported surfaces or lofts or sweeps or spline-driven surfaces, look for faces or splines with an excessive number of defining points or poles. UG/NX has some great tools for examining this.

 

[btrueblood]

I don't know why but I REALLY bristle when told that the model geometry is "invalid" by either the machine or some @%%^#$@%#$ programmer. The geometry shown in the OP's picture looks fine to me, nothing invalid about it. What is meant, and if you hold the programmer's head underwater long enough you will get him to admit, is that the 3D modeling software is not capable of solving the geometry.

 

[ewh]

Depends on the industry... my current employer requires parts to be modeled at nominal, with very few exceptions.

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

 

[looslib]

As for sending the part to GTAC, that should be allowed even if your compnay competes with Siemen's in similar areas of industry. GTAC has very strict rules on who can see a part that they receieve froma customer. I know John Baker has said that even he cannot see a part that has been sent to GTAC for help. Non-disclosure agreements are in place between the companies by nature of the license agreement to use NX.

As others have said, try te NX forum, maybe with a portion of your total part and see if someone else with NX can get the blend you need.



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