JUKI МН-481 Instruction Manual page 38

Troubles
5 Set position of the frame thread eyelet
is not suitable.
6 Position of the thread take-up lever is
not suitable.
7 Throat plate does not fi t.
4. Needle breakage 1 Needle is bent.
2 The timing of the needle motion with
that of needle is not correct.
3 Position of the presser foot is wrong.
4 Motion of the needle guard is not ad-
equate.
5 The tension of needle thread is too
high.
6 Thickness of the needle is not suitable.
5. Puckering 1 Thread tension is too high.
2 Timing of the looper thread take-up is
wrong.
3 Thread paths are not smooth.
4 Pressing force of the presser foot is too
much
5 Needle
6 Throat plate.
6. Puckering 1 Presser foot
2 Pressure of presser foot
Causes
– 28 –
Corrective measures
™ Try to lower the position.
Refer to "25. POSITION OF THE FRAME
THREAD EYELET".
™ Try to push it up.
Refer to "24. POSITION OF THE THREAD
TAKE-UP LEVER".
™ Replace it with other throat plate which has
larger needle hole.
™ Replace it with a straight needle.
Refer to "6. ATTACHING THE NEEDLE".
™ Adjust the timing.
Refer to "17. ADJUSTING THE FEED TIM-
ING".
™ See if the hole of presser foot, hole of throat
plate and loop guide plate are placed in the
center of needle.
™ Check the position and timing of the motion of
the needle guard.
Refer to "22. MATCHING THE MOTION OF
THE NEEDLE GUARDS WITH THE LOOP
GUIDE".
™ Loosen the tension.
Refer to "9. THREAD TENSION".
™ Replace it with a suitable needle in accordance
with the quality and weight of the sewing ma-
terial.
Refer to "6. ATTACHING THE NEEDLE".
™ Reduce the thread tension, especially the
looper thread.
Refer to "9. THREAD TENSION".
™ Set the timing to a little earlier.
Refer to "23. POSITIONING THE LOOPER
THREAD TAKE-UP".
™ Polish the thread path with lapping agent on
thick thread #8.
™ Tighten the adjusting screw.
Refer to "12. ADJUSTING THE PRESSER
FOOT".
™ Use a fi ner needle.
™ Use a throat plate designed for fi ne materials.
™ Ratio of differential feed; Apply 1:0.7 ratio for
gathering.
™ Use a sliding type presser foot.
Refer to "12. ADJUSTING THE PRESSER
FOOT".
™ Reduce the pressure.
Refer to "12. ADJUSTING THE PRESSER
FOOT".