Robotics User Manual

4-28
CHAPTER 4 Adjustment
8) If the machine reference value is not within the tolerance range (26 to 74%)
perform the following steps.
WARNING
The Z-axis will slide down when the Z-axis brake is released, causing a hazard-
ous situation.
• Press the emergency stop button and prop up the Z-axis with a support stand
before releasing the brake.
9) With the robot controller's power ON, apply emergency stop on the control-
ler and release the Z-axis brakes. Refer to the "YAMAHA Robot Controller
owner's manual" for details on emergency stop, releasing emergency stop,
releasing the Z-axis brakes and turning the brakes ON.
10) Loosen the set screw (two screws on upper side) fixing the ball screw in Fig.
4-11 (b), and change the phase of the ball screw in respect to the sleeve as
shown below.
When machine reference 5%:
Turn ball screw 180° clockwise looking from above
When 5% < machine reference < 26%:
Turn ball screw 90° clockwise looking from above
When 74% < machine reference < 90%:
Turn ball screw 90° counterclockwise looking from above
When 90% machine reference:
Turn ball screw 180° counterclockwise looking from above
11) Tighten the set screw and fix the ball screw. The tightening torque is 17kgfcm
(1.7Nm).
12) Exit the safeguard enclosure.
13) Confirm that there no workers in the safeguard enclosure, and then release
the controller emergency stop state.
14) After completing absolute reset for the Z-axis, check to see if the machine
reference value is within the tolerance range for absolute reset.
15) Turn the controller power OFF.
16) Install the Y-axis arm upper cover.