We have the machine set up and calibrated by a representative from Hexagon. After he left, the machine has been consistently off by 0.0007" on the calibration sphere and other ring gages. We have calibrated the probes per the manual, but it is still off by 0.0007. We are running a Brown & Sharpe machine with an FDC controller and Leitz probe. Any ideas would be helpful. Thanks!
Not only can the probe qual ball have the wrong diameter, but the probe tip diameter itself may have the wrong diameter. For the probe tip diameter, go to the probe qual window, click on a probe angle in the file, then click on the 'edit' button. Confirm that the probe ball diameter is correct. I've had people change that (unknown to the rest of us) diameter and it can screw things up for quite a while. There is also an error that will pop up if the probe ball DIA is too far from the value entered --- so if it is NOT too far from the value entered (but still not correct) PC-DMIS will not give you an error. If the DIA is not correct, you can change it there, but you should then check the DIA in all probe angles after that.
Not only can the probe qual ball have the wrong diameter, but the probe tip diameter itself may have the wrong diameter. For the probe tip diameter, go to the probe qual window, click on a probe angle in the file, then click on the 'edit' button. Confirm that the probe ball diameter is correct. I've had people change that (unknown to the rest of us) diameter and it can screw things up for quite a while. There is also an error that will pop up if the probe ball DIA is too far from the value entered --- so if it is NOT too far from the value entered (but still not correct) PC-DMIS will not give you an error. If the DIA is not correct, you can change it there, but you should then check the DIA in all probe angles after that.
Recalibrating the tips will update this value based on the ref sphere size anyway.
Does sound like maybe they altered the ref sphere size (possibly to used their own calibrated/traceable one) during the machine calibration, and didn't change it back.
Recalibrating the tips will update this value based on the ref sphere size anyway.
Does sound like maybe they altered the ref sphere size (possibly to used their own calibrated/traceable one) during the machine calibration, and didn't change it back.
Thanks for the input. The reference sphere used in calibration was verified on our FARO arm and came very close(realizing there is some error in FARO arm readings) to what it says on the side of it.
Thanks for the input. The reference sphere used in calibration was verified on our FARO arm and came very close(realizing there is some error in FARO arm readings) to what it says on the side of it.
IS that the same size as it's defined as within PC-Dmis though?
How can you check a reference sphere with a faro arm ?????????
You're looking for about 18µm, and a good arm has a volumetric accuracy about 25µm... If the hexagon tech came with his sphere and change the value of 18µm, you can't see it with an arm.
You should look at the calibration certificate of your sphere. Maybe the diameter is written on the stem ?
Have a good week-end, all, it's friday !!!!!
