[corndog]

Just starting out here and using a VF2. I'm exploring the VQC page and am able to set tool offsets with the probe on the table and am now moving on to probing the work piece. I'm able to probe X/Y/Z seemingly fine, but I was curious about the offsets the machine recorded. If I manually move X and Y to match what was recorded with the probe, they appear to match up to the corner of the part correctly, but the Z doesn't match up by at least a couple/few inches. I don't remember the exact numbers, but the Z is something like +4.xx when all the way up and about -8.xx when the probe is roughly at the top of the part, but the machine recorded something like -14.xx, is this okay? Is it basically recording where the part is from the bottom of the spindle and not the tip of the probe?

Also, a previous part had been probed and the offset was recorded to G54, but I mistakenly probed to this one to G56. I don't imagine it's a good thing to have multiple work offsets saved this way? I should either delete G54, or copy the info from G56 to G54 and then delete G56?

Finally, is setting the work offset the same as setting the origin? As in, when I draw something up in Mastercam, I should make sure the origin is in the same corner that I probe on the machine?

[RandK]

Pretty short time on my VF also so here's my take: The probe is a tool so it has a length, like all tools, that is calibrated by using the toolsetter and will be positive number. So after probing the z, the work offset should indicate a large negative number indicating the distance from axis zero (spindle plate) to the work surface. Your programs should be using G41 Hxx length compensation so the two add together to locate program z zero.

If you were trying to machine a simple rectangular block drawn in CAD and had a piece of stock clamped in your vise. You would probe the corners to set the work offset to that location but you would want to remove at least a little stock by locating your part origin inside of the stock corners. This can be done by making a manual adjustment to the work offset values.

[Fletch_CNC]

Just starting out here and using a VF2. I'm exploring the VQC page and am able to set tool offsets with the probe on the table and am now moving on to probing the work piece. I'm able to probe X/Y/Z seemingly fine, but I was curious about the offsets the machine recorded. If I manually move X and Y to match what was recorded with the probe, they appear to match up to the corner of the part correctly, but the Z doesn't match up by at least a couple/few inches. I don't remember the exact numbers, but the Z is something like +4.xx when all the way up and about -8.xx when the probe is roughly at the top of the part, but the machine recorded something like -14.xx, is this okay? Is it basically recording where the part is from the bottom of the spindle and not the tip of the probe?

Also, a previous part had been probed and the offset was recorded to G54, but I mistakenly probed to this one to G56. I don't imagine it's a good thing to have multiple work offsets saved this way? I should either delete G54, or copy the info from G56 to G54 and then delete G56?

Finally, is setting the work offset the same as setting the origin? As in, when I draw something up in Mastercam, I should make sure the origin is in the same corner that I probe on the machine?

Yes, the work offset value is the height from machine Z zero.

It doesn't matter how many offsets you have set in the offset page, as long as you are referencing the right one in your program!

Yes, origin in Mastercam and work offset zero are the same thing. You need to set zero on the part the same as you drew it in Mastercam, if you want the part to machine right.

Happy milling!

[corndog]

Thank you very much! Still a little too green to make chips, but I'm getting there.

[Ydna]

To put it another way - your work offset Z value (when probing) is calculated using the machine coordinate for beeping the top of the workpiece, then subtracted down through whatever value is stored in your tool table for the spindle probe. The probe TLO is a positive number, but the control knows to invert it and subtract.
For this reason you can't delete the probe TLO because the control will use an incorrect number for your work offset Z. Fortunately it won't cause a crash, but you'll be machining up in space a couple inches above the workpiece. You'll then need to re-calibrate the spindle probe TLO. I tell people to type it into the "messages" page in case it disappears from your tool table, so you can type it back in.