Offset in CMM

My first inclination would be probe qualification.

You are using more than one head orientation.

If you don't know how to qualify properly, you're going to have error between head rotations.

Lots of threads on probe qualification.

Pick a "Master". It is some build and probably at A0 B0. Use it, if possible, ONLY for qualifying probes.

Measure the qualification sphere with master and say that the sphere has moved, manual hit to locate. Touch the sphere let it run.

All other positions and stylii builds, say NO the sphere has not moved.

If you restart the controller, Master.

If you move the qualification sphere (unscrewing it and screwing it back down moved it), Master.

Qual Master, Yes moved, Manual hit (don't play with DCC hit until you know what you are doing, won't damage anything but taking one hit doesn't hurt).
All other positions and stylus builds, No moved.

If it isn't a disk stylus, DCC + DCC, 25 hits, give it a good spacing off on prehit/retract for qualification.

Thanks for the replay. I think the probe is properly qualified. I did DCC+DCC, 24 hits probe alignment with the first manual touch. The Master is A0B0 orientation because it was used to touch the sphere. The machine took from there and calibrated for the other two orientations. The calibration report indicated perfect deviation.

I don't understand what I am doing wrong.

hi

maybe something simple,
is the correct CAD model used?
Maybe the component is machined incorrectly
wrong raw part?

try checking the component with a steel measure in two places, check whether PLNC and PLNB are really where they should be

Your code in the PDF file looks ok from a distance.
PLNC and PLNB is 0.3 off from nominal, is that because he doesn't hit them correctly?​

Check your part to machine set-up F5 from picture looks wrong to me.

The part is fine, the positions of the features were verified with a calipers.

How did you figure 0.3 distance?

Hi.

the "ACTL" Actuals from PLNC-Y-Value and PLNA-X-Value are 0.3 off.
This is normal if the hit is on the edge of the plane or similar problems. the flatness of these planes should reflect this, should be over 0.3.

if flatness is ok than its odd ^^
The way the program was designed, the difference between the manual values and the DCC values shouldn't actually be big.



Try using only "measured plane" instead of "auto plane" features for manual-Mode, maybe that will work
(I've heard there are problems in some versions if you use auto elements in manual-mode, could be wrong, but is worth a try)​

Alignment A2 should be relative to A1 not STARTUP

A2 =ALIGNMENT/START,RECALL:STARTUP,LIST=YES

it doesn't have to. when i do my dcc alignment i also recall startup

Is this part a machining or moulding and how good are the datum features. Taking PLNA as an example are you just measuring the 1 off small pad area as the datum, from the picture it would appear to show 3 pads that possibly form the datum face if so this could be the cause of the problem with unstable datums defined.

Is this part a machining or moulding and how good are the datum features. Taking PLNA as an example are you just measuring the 1 off small pad area as the datum, from the picture it would appear to show 3 pads that possibly form the datum face if so this could be the cause of the problem with unstable datums defined.

Right?? I'd be measuring a 4 hit plane on each of those pads and then constructing them all together to make one plane