JUKI DDL-555-4 - Page 35

Troubles
Causes Corrective measures
Page
3. Isolated
I) Sewing hook is defective.
0 Replace the sewing hook.
22
idling-
2) Adjust the sewing hook.
o Increase the sewing hook
loops stroke.
("Baloon- 3) Needle is too thin.
o Use a thicker needle.
17
stitch")
4) Feed dog teeth does not Jut
o Increase the height of the
21
out enough from the throat feed dog.
plate surface.
5) Presser foot is not suitable.
o Use a feed dog which has a
wider needle slot and a
larger relief angle on its
bottom face.
6) Needle thread tension is
o Increase the needle thread
16
too low. tension.
7) Tension of the thread take-
o Increa.se the spring tension.
16
up spring is not enough.
4, Wobbling
1) Bobbin thread tension is
o Reduce the bobbin thread
16
or waving too high. tension.
stitches. 2) Needle is too thin.
o Replace the needle.
17
3) Thread is too thick.
o Replace the thread.
17
4) The recess of the needle does
o Insert the needle in the
17
not face to the correct direc correct direction.
tion.
5) Needle bar thread guide.
o Use a .smaller
thread guide.
S. Idle
1) Inclination of the feed dog
o Raise the
front part of the
21
stitching.
is
not proper.
feed dog (front-up position).
2) Presser foot is not suitable.
o Refer to the above 3-(5).
3) Position of the feed dog is
o Move the feed dog closer to
the
not proper. operator.
4) Thread tensions are not
o Reduce the thread tensions.
16
proper.
6. Loose
1) Needle thread tension is
o Increase the needle thread
16
stitch. too low. tension.
2) Bobbin thread tension is
o Reduce the bobbin thread
17
too high. tension.
3) Thread is too thick for the
o Change the combination of
17
needle.
the needle and thread.
4) Thread take-up lever excessive
o Move upwards the thread
25
ly takes up the thread. guide (A) on the arm.
5) Feed timing is too early.
o Delay the feed timing.
20
6) Feed dog teeth does not jut
o Slightly increase the height of
21
out enough from the throat
the feed dog.
plate surface.
7) Thread does not smoothly
o Polish the surface of thread
pass through the sewing hook,
paths.
throat plate, tension discs.
thread take-up or other thread
paths.
o Increase the spring tension.
16
8) Tension of the thread take-up
spring is not enough.
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From the library of: Superior Sewing Machine & Supply LLC