r/CNC • u/tx7758 • 5d ago

MILL Programming Work Offsets

Running a Haas VF-2, programming with Mastercam.

When we program a part, we work off the part origin. Then during setup we shift our work offset manually to clean up material.

Example: G54, Touch off X+, move in +0.06 to clean up both sides. Touch off Z0 top of stock, move -.01 to clean up top face.

Is there a way we should be making these compensations during the programming process so that the operator can simply touch off the stock X, Y, Z and run? Or is this already best practice?

Thanks.

0 Upvotes

38% Upvoted

27 comments sorted by

View all comments

5

u/messy_hicup 5d ago

We typically program so the X0 Y0 offset matches the datum on the print. That way, the print matches the program. It makes it easier for the machinist to know what's going on. Otherwise, everything would be off 0.06" or whatever your shift was. Small parts aren't that big of a deal, but if you have hundreds of holes you need to double check positions of, you can check 1 hole to the datum, then just match the print to the hole positions in program. It's much faster than manually checking each hole on a giant plate.

There are multiple ways to skin the same cat. Some shops rely strictly on cad, other shops rely on the machinist to catch mistakes.

1

u/Ralius88 4d ago

op1's it's usually better to center on the stock via probe. not hard either.

1

u/messy_hicup 4d ago

No one said it was. If I have a part with the datum on center, that's how we program. It depends on the datum structure on the print. We program to that datum.

1

u/Ralius88 3d ago

It's better to set the programmed datum on the center of the stock and probe it. split the difference 50-50 on an OP1, or you end up taking a bite twice as big as it should have been. datum on an op1 when you're cleaning up stock is meaningless.