Service Home How To Procedures UMC C-Axis Z-Pulse & Trip-Flag Clocking - AD0486
Last updated: 10/12/2020

UMC C-Axis Z-Pulse & Trip Flag Reorientation

AD0486

UMC C-Axis Z-Pulse & Trip Flag Clocking - AD0486

Reorientation Procedure

1

  • STOP: Only certified service personnel should perform this procedure. Reorientation of Z-pulse or Trip-Flag will require laser calibration to populate compensation tables with new, correct, values.
  • First, home the B and C-Axis. The platter should be flat in the XY plane and the T-Slots running parallel to the X-Axis.    

2

  • Now, rotate the B-Axis +90° and remove the C-Axis bottom cover.

3

  • Uninstall the encoder hub by removing the 4 screws mounting the encoder hub to the taper-lock. 

4

  • Next, remove the 6 screws mounting the C-axis taper-lock.

5

  • Reposition the trip-flag so that it is positioned as shown. This keeps the sensor from being tripped when the platter is in home position.
  • Once trip-flag is in proper position, reinstall the 6 mounting screws and torque to 30 in-lbf making sure the parts stay in the orientation shown, and the part stays flush to the face of the gearbox shaft.

6

  • Next, use a magnetic field viewer to verify the Z-Pulse location on the encoder ring. Mark it’s location with a permanent marker if it has not been marked already.

7

  • Mount and loosely install the encoder ring assembly assembly so that the Z-Pulse is in positioned as shown. Do not torque yet.

8

  •  Check: With the encoder hub now loosley installed on the taper lock, and the UMC C-Axis in the home position, the following components should be in the orientations shown:
  1. Z-PULSE ENCODER RING
  2. HOME PROX SENSOR
  3. HOME FLAG
  4. ENCODER READ HEAD

9

  • Check and document the runout on the OD of the scale encoder ring hub, as shown in the photo, and adjust as necessary. It must be 0.0005" or less. Now, torque the 4 bolts of the encoder hub to 30 in-lbf.

10

  • Loosen the 2 bolts mounting the encoder read-head and slide it away from the encoder ring.
  •  Then, use an indicator to find the high spot on the OD of the encoder ring.  
  • Mark this high spot with a marker. 
  • Then, rotate the C-Axis so the high spot is positioned as shown
    • Note: Trip-flag and Z-Pulse position do not matter for this step.

11

  • Set the gap between the scale ring and read head as shown [1]  using the apporpriate mylar shim. Do not use a metal shim.
  • Torque the two read head mounting bolts to 20 in-lbf.
  • After torquing, double check the gap with the shim to be the read head has not shifted.
 
  • Reinstall the C-Axis bottom cover being sure no tools, shims, etc. have been left in the casting.
  •  Note: Due to re-clocking of the Z-Pulse and Trip-Flag you will have to set a new tool change offset and update compensation table values for the C-Axis. This will require laser calibration.