Finish CAD and Rough machine part

[Nasejhmoob]

I need help on how to best approach this...I have a finish print with a finish CAD model, but I am to program it to the rough state. When I align everything to the CAD Model, my nominal match the prints, but when I run the Rough part, it doesn't match anymore. My question is how do I change my numbers so that I can use this program to check the rough part? Should I change my theoretical to match the rough theoretical? or how should I go about using a finish cad to program for a rough part? Thanks in advance!

[UKCMM]

There are a number of things you can try.

Get a rough CAD model made.
Adjust the finish CAD nominal
Do not use the CAD and just program from print.
Use the finished CAD model nominal but adjust the tolerances to allow for the rough machine

[bigtallanddopey]

If you know there is 2mm of extra material on you can also add that thickness to your features and keep the same vectors etc.

[Nasejhmoob]

There are a number of things you can try.

Get a rough CAD model made.
Adjust the finish CAD nominal
Do not use the CAD and just program from print.
Use the finished CAD model nominal but adjust the tolerances to allow for the rough machine

Rough CAD model out of the option
How do I adjust finish CAD nominal? Pro-E before loading the CAD Model?
How do I adjust the tolerances to allow for the rough machine? Should I used offsets in my alignments?
I can program without CAD, but there are some holes at a compound angles that I like the cad model for

[UKCMM]

To use tolerances to allow for stock you use +/+ and -/- tolerances so.

If the CAD nom is 25.000 and the rough size need to be 25.4 /25.5 then the plus TOL is 0.5 and the minus TOL is entered as - 0.4 not 0.4.

If the Cad nom is -25.000 the plus TOL is entered as -0.4 and the minus TOL as 0.5

[Nasejhmoob]

If you know there is 2mm of extra material on you can also add that thickness to your features and keep the same vectors etc.

I like to know if I need to include that on my alignment. Example, if I know that finish has .015" less material on X+ axis, can I just make the offset in my alignment X translate at -.015?

[VinniUSMC]

If you know that there is supposed to be a specific amount of material left on the rough part, then you can use the Auto-feature "Thickness" option, set to THEO and put in the material offset. If the rough material is more of a suggestion (ie "leave .010 to .030 material) then this won't work so well.

I'd guess that you're not expected to treat this as a finished part, but that this is just a machining in process verification? If it is, you might be better off using whatever finished features you do have as you alignment, in order to report out those machined features to themselves, and then the rough sections to the finished features. That would require some more communication with engineering/machining to see what is actually needed at this point.

[2013_junkie]

Whenever I'm in this situation I just transform the cad model. So say we are leaving .030" on the face that im picking up, I just transform the model so the trihedran is sitting .030 above the model. Only disadvantage is when you pick points on that face you'll have to adjust the points from .030 back to 0

[Nasejhmoob]

Whenever I'm in this situation I just transform the cad model. So say we are leaving .030" on the face that im picking up, I just transform the model so the trihedran is sitting .030 above the model. Only disadvantage is when you pick points on that face you'll have to adjust the points from .030 back to 0

I was just thinking about the same thing after I post this question. Can I possibly transform my CAD model to match the rough part's origins? I will try this today and find out if the nominal falls into place with rough nominal.

[2013_junkie]

It always works perfectly for me, and in my opinion is the easiest route to go.

[Nasejhmoob]

I transform the cad model to match my rough nominal and everything fall into place nicely. Thanks everyone!