Replacing The Θ-Motor (When The Head Revision Number Is A Or Later) - JUKI RS-1 Maintenance Manual

2-1-14 Replacing the θ-Motor (When the Head Revision Number Is A or Later)
When you replace the existing θ-motor with another one, you have to obtain the MS parameters
related to the origin of each axis again. (See Section 2-2 "Readjustment after Replacement of Head
Unit" for the MS parameters to be obtained again.)
When dismounting the θ motor, clean the θ belt. The (white) characters on the belt are detected by
the sensor at the θ origin return. Therefore, if the characters (color) are light, fill the printing area with
a white marker.
Replace the θ motor with the head dismounted from the machine.
For the [★] parts of the work procedures below, also refer to the work contents of "2-1-12 Replacing
the Head Unit (When the Head Revision Number Is A or Later)" and "2-1-13 Replacing the Z-Motor
(When the Head Revision Number Is A or Later)".
1) ★ Remove the head unit.
2) ★ Remove the head SV bracket and Z motor cable stay.
3) Dismount the Z motor together with the Z motor bracket.
4) ★ Remove the T sensor bracket.
5) Remove the θ-motor mounting screws (4 pcs.) to remove the θ-motor assembly.
* Note
At this time, check the positions marked in "black and white" on the motor pulley.
The position of the black mark is that of the motor Z-phase..
The position of the white mark is that where the eccentricity of the pulley is maximum.
When you replace the motor so that the belt or the shaft (Z axis) cannot be rotated, you can
assemble the new motor easily.
6) Assemble the removed parts and the new motor in the reverse procedure.
7) When you assemble the θ motor, note the following:
① Align the black mark with the (white) characters on the belt.
② Align the position of the white mark on the motor with the position (orientation) of the white
mark on the shaft (spline).
The position of the white mark is the position where the eccentricity of the shaft is maximum.
For the positions of the white marks, align the motor and the positions of the two shafts.
By aligning the position where the eccentricity of the motor pulley is maximum with that
where the eccentricity of the shaft is maximum, the offset value is reduced and the
placement accuracy (θ) is stabilized.
8) Adjust the belt tension as described in <Procedure for adjusting the belt tension> below.
9) After assembling the parts and the new motor, obtain the necessary MS parameters again.
Maintenance Guide
2-49