Offset Plane For Datum

[[Za...]]

I'm having some issues establishing the "Y" datum from this print due to it being an Offset Plane. Is there anybody that can point me in the right direction? I'm aware the picture on the print doesn't match what the CAD looks like in this view, this is due to it being on the other side of the part.

There are only two target points and they are each on different planes.

I've tried a few different things such as creating separate planes/points and recalling them into an Offset Plane, but I get errors and undesirable results for the True Position callout that I need to use it for. Any help is appreciated!

[[To...]]

I can't see the rest of your datum structure but can you just use an RPS Alignment using 3 points on your Z plane, 2 points as described and a point for your X.

[[Za...]]

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This particular part actually has A, B, C, and D datums... and then it has 3 target points for X, 2 target points for Y, and 1 for Z. I've never seen anything called out like this before. I'll attach as much as I can of the print and see if that will help you help me 🙂.

Thanks,

Zach

[[Za...]]

Does this help?

[[Ri...]]

Y should be a Line, not a Plane.

In this case, you can create a formula that pulls the actual of one, and offsets it the nominal value.

I haven't seen this on the secondary datum much, but this is common on the primary datum.

[[Za...]]

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I'm not familiar with how to do that at all. Do you have any references I could look at/follow?

Thanks

[[Er...]]

This may be what they were saying.

Try pulling Y1 into a point and Y2 into a point.
Then take say, Y1 and pull it into a theoretical point. Use a formula to pull the actual value for the offset axis. Add or subtract the BASIC value.
Make a 3d line and pull the theoretical point and Y2.

[[Ma...]]

I would highly recommend using start alignment. I don't believe it wil calculate right direction of offsetted point.

[[Er...]]

I avoid any constructed features in Base Alignments. In training it was stressed the Base Alignment is PRIMARILY for finding the parts consistently. If the program can't do that then all is lost.

It is convenient to use the primary datum scheme for the BA but is not necessary.

When we have two part fixtures with tooling balls I zero on one sphere and orientate to the CMM just using the spheres. Then I create a 3D Best Fit alignment using the spheres and input the coordinates of the tooling balls into the alignment. The reason for the extra step is so I can guarantee Mirror the program. Very frustrating to have the Block Edges making it impossible to use a mirrored program.