Calibrating the workpiece touch probe

Application

In order to precisely specify the actual trigger point of a 3D touch probe, you must first calibrate the touch probe, otherwise the control cannot provide precise measuring results.

During 3D calibration, you determine the angle-dependent deflection behavior of a workpiece touch probe in any probing direction (option 92).

Description of function

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During calibration, the control finds the effective length of the stylus and the effective radius of the ball tip. To calibrate the 3D touch probe, clamp a ring gauge or a stud of known height and known radius to the machine table.

The effective length of the workpiece touch probe refers to the tool carrier preset.

Tool carrier reference point

You can calibrate the workpiece touch probe with various tools. For example, the workpiece touch probe can be calibrated using an overmilled surface in length and a calibration ring in the radius. This creates a reference between the workpiece touch probe and the tools in the spindle. In this procedure, measured tools and the calibrated workpiece touch probe correspond using the tool presetting device.

3D calibration (option 92)

In addition to calibrating with a calibration sphere, the control also enables the touch probe to be calibrated dependent on the angle. For this purpose the control probes the calibration sphere in a quarter circle in the perpendicular. The 3D calibration data specifies the deflection behaviour of the touch probe in any probing direction.

The control saves the deviations in a compensation value table *.3DTC in the folder TNC:\system\3D-ToolComp.

The control creates a specific table for each calibrated touch probe. In the tool table the DR2TABLE column is automatically referenced to this.

3D-Kalibrierung
3D calibration

Reversal measurement

When calibrating the ball-tip radius, the control executes an automatic probing routine. In the first run the control finds the midpoint of the calibration ring or stud (approximate measurement) and positions the touch probe in the center. Then, in the actual calibration process (fine measurement), the radius of the ball tip is ascertained. If the touch probe allows probing from opposite orientations, the center offset is determined during another cycle.

HEIDENHAIN touch probes are predefined as to whether or how a touch probe can be oriented. Other touch probes are configured by the machine manufacturer.

When calibrating the radius, up to three circular measurements can be taken depending on the possible orientation of the workpiece touch probe. The first two circular measurements determine the center offset of the workpiece touch probe. The third circular measurement determines the effective stylus tip radius. If orientation of the spindle is not possible or only a certain orientation is possible due to the workpiece touch probe, circular measurements are omitted.

Calibrating the length of the workpiece touch probe

  1. To calibrate a workpiece touch probe using an overmilled surface in length:
  2. Measure the end milling cutter on the tool presetting device
  3. Store the measured end milling cutter in the tool magazine of the machine
  4. Enter the tool data of the end milling cutter in tool management
  5. Clamp the workpiece blank
ManualMainIcon

  1. Select the Manual operating mode

  1. Replace the end milling cutter in the machine
  2. Switch on spindle, e.g. with M3
  3. Use the handwheel to scratch the workpiece blank
  4. Setting a preset with milling cutters

  5. Set preset in the tool axis, e.g. Z
  6. Position the end milling cutter next to the workpiece blank
  7. Set a small value in the tool axis, e.g. -0.5 mm
  8. Overmill the workpiece blank using the handwheel
  9. Set the preset again in the tool axis, e.g. Z=0
  10. Switch off spindle, e.g. with M5
  11. Replace the tool touch probe
  12. Select the Setup application
cal

  1. Select Calibrate touch probe
measCalLen

  1. Select the Length calibration measurement method
  2. The control displays the current calibration data.
  3. Enter the reference surface position, e.g. 0
  4. Position the workpiece touch probe close to the surface of the overmilled area
  5.  
    Tip

    Check that the area to be probed is flat and free of chips before you start the touch probe function.

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  1. Press the NC start key
  2. The control performs the probing process and then automatically retracts the workpiece touch probe to the starting point.

  1. Check results
SF_5_Kalibrierdaten_uebernehmen

  1. Select Apply calibration data
  2. The control transfers the calibrated length of the 3D touch probe to the tool table.
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  1. Select Exit probing
  2. The control closes the Calibrate touch probe function.

Calibrating the radius of the workpiece touch probe

  1. To calibrate a workpiece touch probe using a setting ring in the radius:
  2. Clamp the setting ring on the machine table, e.g. with clamps
ManualMainIcon

  1. Select the Manual operating mode
  2. Position the 3D touch probe in the hole of the setting ring
  3.  
    Tip

    Make sure that the stylus tip is completely recessed into the calibration ring. This causes the control to probe with the largest point of the stylus tip.

  4. Select the Setup application
cal

  1. Select Calibrate touch probe
measCalCircle

  1. Select Radius measurement method
RadiusKalibrierring

  1. Select Setting ring calibration standard

  1. Enter the diameter of the ring gauge

  1. Enter the start angle

  1. Enter the number of touch points
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  1. Press the NC Start key
  2. The 3D touch probe probes all required touch points in an automatic probing routine. The control calculates the effective stylus tip radius. If probing from opposite orientations is possible, the control calculates the center offset.
  3. Check results
SF_5_Kalibrierdaten_uebernehmen

  1. Select Apply calibration data
  2. The control stores the calibrated radius of the 3D touch probe in the tool table.
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  1. Select Exit probing
  2. The control closes the Calibrate touch probe function.

3D calibration of workpiece touch probe (option 92)

  1. To calibrate a workpiece touch probe using a calibration sphere in the radius:
  2. Clamp the setting ring on the machine table, e.g. with clamps
ManualMainIcon

  1. Select the Manual operating mode
  2. Position the workpiece touch probe centrally above the sphere
  3. Select the Setup application
cal

  1. Select Calibrate touch probe
measCalCircle

  1. Select Radius measurement method
RadiusKalibrierkugel

  1. Select the Calibration sphere calibration standard

  1. Enter the diameter of the sphere

  1. Enter the start angle

  1. Enter the number of touch points
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  1. Press the NC Start key
  2. The 3D touch probe probes all required touch points in an automatic probing routine. The control calculates the effective stylus tip radius. If probing from opposite orientations is possible, the control calculates the center offset.
  3. Check results
SF_5_Kalibrierdaten_uebernehmen

  1. Select Apply calibration data
  2. The control stores the calibrated radius of the 3D touch probe in the tool table.
  3. The control shows the 3D calibration measurement method.
measCal3d

  1. Select the 3D calibration measurement method

  1. Enter the number of touch points
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  1. Press the NC Start key
  2. The 3D touch probe probes all required touch points in an automatic probing routine.
SF_5_Kalibrierdaten_uebernehmen

  1. Select Apply calibration data
  2. The control saves the deviations in a compensation value table under TNC:\system\3D-ToolComp.
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  1. Select Exit probing
  2. The control closes the Calibrate touch probe function.

Instructions for calibration

  • In order to be able to determine ball-tip center misalignment, the control needs to be specially prepared by the machine manufacturer.
  • If you press the OK button after the calibration process, the control accepts the calibration values for the active touch probe. The updated tool data then becomes immediately effective, and it is not necessary to repeat the tool call.
  • HEIDENHAIN only guarantees the proper operation of the touch probe cycles in conjunction with HEIDENHAIN touch probes.
  • If you want to calibrate using the outside of an object, you need to pre-position the touch probe above the center of the calibration sphere or calibration pin. Ensure that the probing points can be approached without collisions.
  • The control saves the effective length and effective radius of the touch probe in the tool table. The control saves the touch probe center offset in the touch probe table. The control uses the TP_NO parameter to link the data from the touch probe table with the data from the tool table.
  • Touch probe table tchprobe.tp