Robin, I think the question is too generic to answer correctly.

I often hold down anyway I can onto sacrificial plates.
I then program the part to cut all the entities but the first few lines drill thru the part on programmed holes with a tapping size drill into the sacrifical plate.

I then stop the program, remove the part, drill the part holes out from tapping to size, tap the holes in the plate and bolt the part back to the plate.

I then rewind the program and block out / delete the first drilling cycle and carry on with the parts. Any subsequent parts are drilled using the first one as a pattern so I know they will fit the sacrificial plate.

Doesn't apply to all parts as it need some holes in the part or holes into places that don't matter.

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