Understanding Calibration Results

I don't usually look at the probe calibration results because I don't really understand what I'm looking at. I'd really like to gain a firm understanding of the data and what it should mean to me.

I've been digging through old threads, and I'm getting closer. What I think I get is that StdDev is the standard deviation of single-point error of the measured sphere for each tip angle. (I was told by another inspector here that that number should be .0002 or less.) I also understand that the MEAS D determines the effective probe diameter for each tip, and is used for probe size compensation.

I don't fully understand the THEO/MEAS XYZ (where the THEO comes from, what the MEAS means), or what is a maximum permissible error. What do you guys look for when you read your calibration results? What do you hope to learn from the numbers? What do you consider to be a red flag?

Parents

TheBradish over 10 years ago

Looks like you're right about that. I just compared the difference in THEO Z for two of my probes (A0B0) and the difference in Z matches the difference in stylus length. I also compared the THEO Z of my master probe to the total length of my Renishaw hardware (using nominals from the Renishaw site) and they match within a couple mm.

From looking at my results, it looks like my probe head might be slightly out of square. But if the qualification routine compensates for that, will it really make a difference? How much is too much? Here are some of my results for a 1x30 tip:

AUTOCALIBRATE/PROBE, PARAMETER_SET=ALL-TIPS-WITH-DEFAULTS, QUALTOOL_MOVED=YES,                           SHOW_SUMMARY=YES, OVERWRITE_RESULTSFILE=YES
BEGIN AUTOCALIBRATE RESULTS FOR PROBE MASTER USING SET ALL-TIPS-WITH-DEFAULTS
Probe file=MASTER    Date=11/17/2014    Time=4:37:04 PM
BALL IN STAND  CENT X35.152186 Y48.827637 Z-37.963942 D0.983550
T1A0B0         THEO X  0.00000 Y  0.00000 Z  5.96535 D0.15748
T1A0B0         MEAS X  0.00000 Y  0.00000 Z  5.96535 D0.15733 StdDev0.00003
END AUTOCALIBRATE RESULTS FOR PROBE MASTER USING SET ALL-TIPS-WITH-DEFAULTS


AUTOCALIBRATE/PROBE, PARAMETER_SET=ALL-TIPS-WITH-DEFAULTS, QUALTOOL_MOVED=NO, 
                          SHOW_SUMMARY=YES, OVERWRITE_RESULTSFILE=NO
BEGIN AUTOCALIBRATE RESULTS FOR PROBE 1MM X 30MM USING SET ALL-TIPS-WITH-DEFAULTS
Probe file=1MM X 30MM    Date=11/17/2014    Time=8:47:47 PM
T1A30B-180     THEO X  0.00000 Y -2.68740 Z  6.03267 D0.03937
T1A30B-180     MEAS X -0.04038 Y -2.68127 Z  6.03372 D0.03874 StdDev0.00006
T1A37.5B-180   THEO X  0.00000 Y -3.27197 Z  5.64207 D0.03937
T1A37.5B-180   MEAS X -0.04254 Y -3.27025 Z  5.64188 D0.03873 StdDev0.00008
T1A37.5B-172.5 THEO X  0.42708 Y -3.24398 Z  5.64207 D0.03937
T1A37.5B-172.5 MEAS X  0.38588 Y -3.24671 Z  5.64099 D0.03874 StdDev0.00008
T1A45B-180     THEO X  0.00000 Y -3.80056 Z  5.17851 D0.03937
T1A45B-180     MEAS X -0.04481 Y -3.80282 Z  5.17663 D0.03874 StdDev0.00007
T1A45B-172.5   THEO X  0.49607 Y -3.76805 Z  5.17851 D0.03937
T1A45B-172.5   MEAS X  0.45315 Y -3.77486 Z  5.17559 D0.03878 StdDev0.00007
T1A37.5B-165   THEO X  0.84685 Y -3.16048 Z  5.64207 D0.03937
T1A37.5B-165   MEAS X  0.80732 Y -3.16749 Z  5.64026 D0.03872 StdDev0.00009
T1A37.5B165    THEO X -0.84685 Y -3.16048 Z  5.64207 D0.03937
T1A37.5B165    MEAS X -0.89041 Y -3.15117 Z  5.64251 D0.03877 StdDev0.00005
T1A37.5B172.5  THEO X -0.42708 Y -3.24398 Z  5.64207 D0.03937
T1A37.5B172.5  MEAS X -0.46934 Y -3.23901 Z  5.64190 D0.03875 StdDev0.00006
T1A22.5B180    THEO X -0.00000 Y -2.05685 Z  6.34362 D0.03937
T1A22.5B180    MEAS X -0.03730 Y -2.04704 Z  6.34485 D0.03880 StdDev0.00007
T1A30B180      THEO X -0.00000 Y -2.68740 Z  6.03267 D0.03937
T1A30B180      MEAS X -0.04040 Y -2.68133 Z  6.03368 D0.03874 StdDev0.00009

Reply

TheBradish over 10 years ago

AUTOCALIBRATE/PROBE, PARAMETER_SET=ALL-TIPS-WITH-DEFAULTS, QUALTOOL_MOVED=YES,                           SHOW_SUMMARY=YES, OVERWRITE_RESULTSFILE=YES
BEGIN AUTOCALIBRATE RESULTS FOR PROBE MASTER USING SET ALL-TIPS-WITH-DEFAULTS
Probe file=MASTER    Date=11/17/2014    Time=4:37:04 PM
BALL IN STAND  CENT X35.152186 Y48.827637 Z-37.963942 D0.983550
T1A0B0         THEO X  0.00000 Y  0.00000 Z  5.96535 D0.15748
T1A0B0         MEAS X  0.00000 Y  0.00000 Z  5.96535 D0.15733 StdDev0.00003
END AUTOCALIBRATE RESULTS FOR PROBE MASTER USING SET ALL-TIPS-WITH-DEFAULTS


AUTOCALIBRATE/PROBE, PARAMETER_SET=ALL-TIPS-WITH-DEFAULTS, QUALTOOL_MOVED=NO, 
                          SHOW_SUMMARY=YES, OVERWRITE_RESULTSFILE=NO
BEGIN AUTOCALIBRATE RESULTS FOR PROBE 1MM X 30MM USING SET ALL-TIPS-WITH-DEFAULTS
Probe file=1MM X 30MM    Date=11/17/2014    Time=8:47:47 PM
T1A30B-180     THEO X  0.00000 Y -2.68740 Z  6.03267 D0.03937
T1A30B-180     MEAS X -0.04038 Y -2.68127 Z  6.03372 D0.03874 StdDev0.00006
T1A37.5B-180   THEO X  0.00000 Y -3.27197 Z  5.64207 D0.03937
T1A37.5B-180   MEAS X -0.04254 Y -3.27025 Z  5.64188 D0.03873 StdDev0.00008
T1A37.5B-172.5 THEO X  0.42708 Y -3.24398 Z  5.64207 D0.03937
T1A37.5B-172.5 MEAS X  0.38588 Y -3.24671 Z  5.64099 D0.03874 StdDev0.00008
T1A45B-180     THEO X  0.00000 Y -3.80056 Z  5.17851 D0.03937
T1A45B-180     MEAS X -0.04481 Y -3.80282 Z  5.17663 D0.03874 StdDev0.00007
T1A45B-172.5   THEO X  0.49607 Y -3.76805 Z  5.17851 D0.03937
T1A45B-172.5   MEAS X  0.45315 Y -3.77486 Z  5.17559 D0.03878 StdDev0.00007
T1A37.5B-165   THEO X  0.84685 Y -3.16048 Z  5.64207 D0.03937
T1A37.5B-165   MEAS X  0.80732 Y -3.16749 Z  5.64026 D0.03872 StdDev0.00009
T1A37.5B165    THEO X -0.84685 Y -3.16048 Z  5.64207 D0.03937
T1A37.5B165    MEAS X -0.89041 Y -3.15117 Z  5.64251 D0.03877 StdDev0.00005
T1A37.5B172.5  THEO X -0.42708 Y -3.24398 Z  5.64207 D0.03937
T1A37.5B172.5  MEAS X -0.46934 Y -3.23901 Z  5.64190 D0.03875 StdDev0.00006
T1A22.5B180    THEO X -0.00000 Y -2.05685 Z  6.34362 D0.03937
T1A22.5B180    MEAS X -0.03730 Y -2.04704 Z  6.34485 D0.03880 StdDev0.00007
T1A30B180      THEO X -0.00000 Y -2.68740 Z  6.03267 D0.03937
T1A30B180      MEAS X -0.04040 Y -2.68133 Z  6.03368 D0.03874 StdDev0.00009

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