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rotary table autocalibration?

jleond
Does anyone use some kind of script, subroutine, program or wahtever for rotary table autocalibration? The table is firmly bolted to the granite, but still moves a few ten thousandths from time to time, this causes erroneous or suspicious results of diameters when the table is used for these purposes. What I'm looking for is to streamline the calibration process and automate it as a probe and RT calibration routine.

Thanks.
  • Just create a prog starting by IGNOREROTAB/ON, which measure the rotary calibration sphere in different locations (the rotary turns in the CMM alignment)
    Then, create a plane from sphere centers, and a circle from them also.
    The circle gives XYZ, the plane IJK.
    Then use the Setrotabdata function.
    Hope this helps.

    SETROTABDATA

    This function sets the center or vector to the new input value: SETROTABDATA(<PARAMETER>,<NewValue>[,


























    ]) This function works in the following configurations:• Single rotary table• Dual (independent) rotary tables• Stacked rotary tablesCENTER• "CENTER",<NewValue> - Sets the rotary table's XYZ center to the new value.• "CENTER",<NewValue>,"V" - Sets the XYZ center for rotary table V in a dual-table or stacked-table configuration to the new value.• "CENTER",<NewValue>,"W" - Sets the XYZ center for rotary table W in a dual-table or stacked-table configuration to the new value.Examples:ASSIGN/V1=SETROTABDATA("CENTER",NewValue)V1 is a return code (1=success, 0=failure). ASSIGN/V1=SETROTABDATA("CENTER",NewValue,"V")V1 is a return code (1=success, 0=failureASSIGN/V1=SETROTABDATA("CENTER",NewValue,"W")V1 is a return code (1=success, 0=failure).VECTOR• "VECTOR",<NewValue> - Sets the rotary table's IJK vector to the new value.• "VECTOR",<NewValue>,"V" - Sets the IJK vector for rotary table V in a dual-table or stacked-table configuration to the new value.• "VECTOR",<NewValue>,"W" - Sets the IJK vector for rotary table W a dual-table or stacked-table configuration to the new value.Examples:ASSIGN/V2=SETROTABDATA("VECTOR",NewValue)V2 is a return code (1=success, 0=failure).ASSIGN/V2=SETROTABDATA("VECTOR",NewValue,"V")V2 is a return code (1=success, 0=failure).ASSIGN/V2=SETROTABDATA("VECTOR",NewValue,"W")V2 is a return code (1=success, 0=failure).Another way, less accurate, consists in measuring the calibration sphere (if it's stay in place) as a sphere, calculate the deviations from GETQUALTOOLDATA("xyz", "sphere_name") and aplly the deviations to the rotary center (I assume that the vector doesn't change, which could be logical...)
  • in reply to JEFMAN
    Thanks Jefman!

    Is it possible that the repeatability of the home position affects the calibration of the rotary table?
  • in reply to JEFMAN
    Yes, the home position is not always repeatable - especially on older machines where it is a magnetic switch rather than a mark on the reference scale. This is why it askes if the calibration sphere has been moved or the machine home position been updated when calibrating probes. In extreme cases it can also cause problems loading / unloading to a probe rack.
  • Hey , what kind of rotary table do you have? Make and model?
  • Another important parameter to take into account is the thermal compensation.
    Select "compens axes only", (turn of the compensation of the part).
  • From 2019R1 :
    Added option IGNOREROTAB/CALIBRATION. With this option, users will be able to calibrate rotary tables using measurement routing. This function was mainly added to support the rotary table that use error compensation map. But it can be used with tables that use or do not use error compensation.
  • in reply to vpt.se
    Is a RPI QSL 600 Grade 1 Rotary Table
  • in reply to JEFMAN
    Yes, that is what I also found in the help files, thanks.
  • Have you considered using a tool setter or a touch probe for your calibration routine? They can help ensure more precise measurements and streamline the process as well.
  • Hi there! It sounds like you're having some trouble with your rotary table, and you're looking for ways to automate the calibration process.
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