JUKI LU-2810 Series Engineer's Manual page 76

海外講習会用121122 LU-2810(-7)_EM
WARNING :
Turn �FF the power before starting the work so as to prevent accidents caused by abrupt start of the sewing machine.
Trouble
7. Irregular stitches
8. Loose stitches at the time of corner
stitching
Adjustment of the thread take-up spring
o
Cause
7-1) Stroke of the thread take-up
spring is improper.
7-2) Thread paths have been
poorly finished.
7-3) Bobbin fails to move
smoothly.
7-4) Bobbin thread tension is too
low.
7-5) Bobbin has been wound too
tight or too weak.
7-6) Direction of setting bobbin is
reverse.
8-1) Needle thread on the stop-
ping side is drawn out more
than is necessary.
Decrease the tension of the thread take-up spring and decrease the stroke of the spring to improve irregular stitches.
Checking
1-A) Check the stroke of the
thread take-up spring.
2-A) Check the finish of the re-
spective thread paths.
3-A) Check the change of bobbin
thread tension.
5-A) Check the state of bobbin
winding.
6-A) Check the setting.
1-A) Check the stroke of the
thread take-up spring.
1-B) Check the hook timing.
Corrective measures
Adjust the thread take-up spring to move to ap-
proximately 1 mm from the initial position when
hook draws thread maximumly.
Finish with a fine emery paper or buff.
Replace the bobbin or the hook with new ones.
Increase the tension of the bobbin thread.
Decrease or increase the tension applied to the
bobbin winder.
Properly set the bobbin.
In crease the stroke of the thread take-up
spring.
Retard the hook timing.
Use the optional walking foot. (Top divided type)