Can I adjust my datum?

[[Ra...]]

Can I adjust my datum?

This part is 13”x19”, and I was planning to clamp it again on the table. However, I noticed that Datum A will be at the back of the part. In order to check the true position, I need Datum A, but I won’t be able to scan this area.

What solutions are available?

I was considering clamping the part vertically, but that may cause other issues.

Thank you,

[[Ma...]]

I woul avoid this aproach.
Rather you would scan table prior to clamping or take rest of unused table to form (A).

Or you can make new program where you will scan table and place origin on table and point close to center of part.
Then in your program you will load stored alignment and make theoretical plane with that alignment - edit nominals to zeros for that plane and use that as primary in your alignment and Z origin.

[[Ra...]]

Thank you, 

[[Da...]]

I have a part with this issue coming soon, and we will have an inspection fixture to allow access to the backside datum A. I also have a screw-hole plate on the CMM, and 2 of these ~250mm high uprights, which I will clamp the fixture to standing up. Oh, and I'll also have to measure holes with a Ø.035", and already have some 0.5mm tips ready. It's gonna be fun...

On smaller parts, I've used my Renishaw mounting kit to stage a part on 3 separate skinny 150mm risers, then probe the bottom from2 or 3 different directions, avoiding the uprights.

Edited January 10