Service Home How To Procedures C Axis - Grid Offset - Adjustment - ST - SL
Last updated: 06/29/2023

C Axis - Grid Offset - Adjustment - ST - SL

ST/SL Lathe - C Axis - Grid Offset - Adjustment

1

Remove the enclosure panels in the order shown.

2

Disconnect the air supply [1] to the actuator block for the C axis.

3

Install the air regulator and cutoff valve on the actuator air supply hose.

Connect the air supply and set the regulator.

 Note: For an SL Lathe, set the air pressure on the regulator to 45 PSI. For an ST Lathe, set the regulator to 85 PSI.

Go into DEBUG mode.

Change Parameter 517 C GRID OFFSET to 0.

[ZERO RETURN] the C Axis.

Set Parameter 278:26 C AXIS DRIVE to 0.

Set Parameter 498:3 C AXIS DISABLED to 1.

4

Type M19 in MDI mode.

Press [CYCLE START].

5

Open the cutoff valve to engage the actuator block.

6

The C-axis gears must engage correctly. Use an inspection mirror to see the gears engage. Turn the C-Axis motor with your hand. Turn the motor gear until the gears align. Turn the C-Axis motor gear until they engage.

Press [POSIT].

7

 Note: On an ST-40, you cannot rotate the gears with your hand. Put a flat-head screwdriver through the hole. Use the screwdriver to turn the motor. Turn the motor until the gears align.

8

Navigate to the Pos-Raw Dat 1 data page.

Record the value in the C AXIS ACTUAL column. For Sigma-1 motors, the value is between +/- 1260. For ST-40 and larger with Sigma-5 motors, the value is between +/- 50400. For all other Sigma-5 lathes, the value is between +/- 10080.

9

Set the value in Parameter 517 C GRID OFFSET. Use the recorded value in the C AXIS ACTUAL column.

For this example, the value is 261.

10

Release the air from the actuator block.

11

Set Parameter 498:3 DISABLED to 0.

12

[ZERO RETURN] the C Axis. The value in C AXIS ACTUAL is 0.

13

Open and close the cutoff valve to engage the actuator block. The value in C AXIS ACTUAL must stay at 0.

14

Remove the air regulator and cutoff valve from the air supply tube for the actuator.

Connect the air-supply tube to the actuator block for the C Axis.

15

Set Parameter 278:26 to 1.

16

Type M154; M155; M99; in MDI mode.

Press [CYCLE START].

If the adjustment is correct, the machine orients the spindle and correctly engages the c-axis. If an alarm occurs, make sure the grid offset is correct. And examine the pulley for the spindle encoder.