#### Ring Calibration

Ring calibration is good for measurements in the XY plane (if the probe is pointing in Z).

1. Press the Probe soft key from the Main screen.

2. Press the Ring Calibration soft key to display the Ring Calibration screen.

3. Follow the on-screen instructions then click the Confirm soft key to complete the procedure or press the Return soft key to return to the previous screen without saving.

Parameter Definitions:

- Tip Diameter (Probe/Nominal) - Provides the nominal diameter of the probe tip. The Measured value is updated when calibration completes.

- Diameter (Ring) – Specifies the diameter of the Calibration/Qualification ring.

- XYZ (Ring/Center) - Specifies the top surface center location of the qualification ring in relation to the Work Offset location. The Z value will be used to compute the probe Z offset with the last point on the surface. This value should be 0,0,0 if the ring was accurately positioned at the Work Offset.

- Feed Rate - Sets the speed in millimeters per minute (or inches per minute) that the probe will travel during probe calibration.

- Prehit Distance - Specifies the distance from the theoretical hit location to which the probe will move before taking a hit. This is used during probe calibration. This is in millimeters or inches.

- Work Offset - Specifies the Work Offset at which the qualification ring is located. Choose Machine to move relative to Machine coordinates.

Navigation Bar Soft Keys for this Screen:

| Find Center Selecting this soft key will cause the software to take sample hits to find the center of the ring before measuring the ring for calibration. |  |
|  |  | View Calibration Report Select this soft key to view the available calibration report.

Calibration Process:

1. Select a Work Offset to use for the calibration. The default is the Machine work offset.

2. Input the Diameter and Center Location for the Calibration/Qualification ring. The user may identify the location center coordinates using the description at the bottom of this page

3. Input the other parameters described in the Parameter Definitions section above.

4. Jog the probe to a position near the center of the ring.

5. Click on the Execute soft key . NC Gage automatically takes 4 hits on the qualification ring to determine the center of the ring. After the center of the ring is more accurately determined, the bore of the ring gage is measured with 36 hits and the top of the ring gage is measured with a single hit.

Note: The four point measurement sequence is skipped if the Find Center sequence was performed and the probe has not moved after finding the ring center. In this case the ring gage bore is immediately measured with 32 hits followed by the single hit measurement of the ring gage top. - no longer need according to Chuck's e-mail of 08.04.2011

6. Once calibration has completed, the measured values are updated. Press the Show Details soft key to view the Tip Offset details or the Confirm soft key to save the calibration results and return to the Main screen. You are now ready to measure features using the calibrated probe.

Note: The Tip Details can also be viewed by selecting the Show Details check box.

Locating XY:

- With Spindle Rotation - If the NC Machine supports spindle orientation (M19Sxxx), then the XY position of the ring may be found with the Find Center apply function in the Calibration screen. This function rotates the spindle for each point so that runout of the probe tip is not a factor.

Locating Z:

- Insert a reference tool of known length into the spindle.

- With a feeler gage of known thickness, jog the tool down over the top of the ring until the feeler gage has resistance when moving between the ring and the tool. Use the smallest jog increment when close to the ring.

- The ring top surface Z is then equal to machine Z minus the feeler gage thickness minus the reference tool length.

The following is the specific feature path and logic built into NC Gage:

- Read position of probe in center of ring.

- Ring measurements will occur at Z value of read point.

- Estimate XY center of ring to be read position point.

- Set prehit radius = Ring Radius - probe radius - prehit distance.

- Set target radius = Ring Radius + prehit distance.

- Set safe height = read position Z value + 25 mm.

- Measure ring with 36 points from 0 to 350 degrees.

- Move to safe height.

- Move in safe height to a point that is Ring Radius + 2* probe radius in +X direction from ring center.

- Measure straight down, target height is same height as ring points.

- Return to safe height.