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Cylinder probe calibration issues

Hello all.
I have been having an issue with a custom cylinder probe for a while now. A forum friend of mine has previously helped me, but I don't want to bother him yet AGAIN. The cylinder probe is a 3mm (dia) x 13mm (length from tip to thread shoulder) with a 20mm extension. I had to tear the probe down a couple of days ago because another job came up. Well, I'm back on the job that needs that probe so I built it again. When I calibrated it this time, it comes up w/ the error "measured probe diameter exceeds limits". The 3mm cylinder checks anywhere From 3.290mm to 3.330mm. For some reason it's NOT calibrating around the equator of the sphere. In all honesty, I guess it doesn't really matter for THIS job, since I only need the probe to check in the Z direction. But what IF I ever need this probe to check diameters? I'm screwed. I contacted Hexagon back in May of last year when we first bought the probe because it wasn't in the drop down menu. I was on the phone for 2 or 3 days with the guy, and he had control of my computer. NEVER could get the probe to read diameters correctly. I finally gave up because I only needed the Z direction. Here is the usrprobe file. Can anybody PLEASE help me? Thank you in advance.

ITEM:TIP3BY13MM_CYL_PART_268 M2
EffectiveWorkingLength 13.0
begintip
ribcount 10
color 80 80 80
cylinder 0 0 0 0 0 -2.5 3
cone 0 0 -2.5 3 0 0 -5.5 2.0
color 80 80 80
cylinder 0 0 -5.5 0 0 -7.5 2.0
cone 0 0 -7.5 2.0 0 0 -9.0 3.0
cylinder 0 0 -9.0 0 0 -12.8 3.0
cone 0 0 -12.8 3.0 0 0 -13 2.8
sphere 0 0 -11.5 3.0
hotspot 0 0 -11.5 0 0 1 3.0 3.0 shank
endtip


Probe file=3X13 CYL PROBE +20 Date=2/8/2024 Time=1:46:41 PM

T1A0B0 THEO X 0.000 Y 12.000 Z 213.075 D 3.000
T1A0B0 MEAS X -0.058 Y 11.961 Z 214.065 D 3.290 StdDev 0.002

Measured probe diameter error exceeds the limits.
T1A0B0

Parents Reply Children
  •   As I've mentioned before, there is a 1mm offset being introduced to the length from somewhere.  The THEO length is 13.075mm.  The first time you calibrate after resetting the tip, The MEAS length is set to the same as the THEO and PC-DMIS uses that length to drive the tip around the cal sphere.  It then updates the MEAS length to what was actually recorded during the calibration which is where your 1mm offset gets added in.  The next time you calibrate, PC-DMIS uses the updated MEAS length to drive the probe around the sphere and it tries to take hits 1mm higher up.  Because it is a flat bottomed cylinder, rather than a sphere, the corner of the cylinder hits higher up the sphere and the diameter shows out.

    .

    This can ONLY happen if one or more of the components making up your probe build has a different physical length than the one that is defined.  You have previously told me that you've measured your cylinder component and that it has the correct length, what about other components - extensions, probe module, indexing head, adaptors between the head and the Z ram?  Have you looked at the results for all of your other probe builds to see if any of those have differences between their THEO and measured lengths?