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23. TROUBLES IN SEWING AND CORRECTIVE MEASURES
Troubles
1
Thread breakage
2
Stitch skipping
(on the right side of cloth)
Stitch skipping
(on the wrong side of cloth)
3
Hangnail of thread
4
Thread tension defect
5
Fabric yarn breakage
(run)
6
Chain-off thread does not
come out.
7
General sewing trouble
(In case of spun thread
or the like)
8
Broken material occurs
when the material made of
synthetic knit yarn is used.
9
Thread pulling occurs
when thin material is used.
10
The overlapped section
cannot be ridden out.
Causes
Thread path, looper point or spreader
point has a scratch.
Thread tension is too high.
An excessive clearance is provided
between looper and needle.
Timing between needle and looper is not proper. Readjust the timing.
Clearance provided between looper
and needle is too small.
Loop on the right side of cloth is
fallen.
There is a difference in level in the
sewing product.
Sewing needle fails to pierce the loop
on the right side of cloth.
Looper fails to catch thread.
Spreader fails to catch thread.
Looper top or spreader top has a
scratch.
An excessive clearance is provided
between looper and needle.
Spreader fails to catch thread.
Thread is thick for the hook needle.
Thread tension is too high.
Loop on the right side of cloth is too
large.
Loop is excessively tightened.
Thread tension is too high.
Hook needle has burrs.
Chain-off thread is hard to come out
due to the condition of pulling cloth.
Thread tension is too low or too high.
Chain-off thread skips due to rough
motion of thread.
In case large-resistance thread such as
spun thread or the like is used, when
there are many threading portions
such as thread guide and the like, the
change of thread tension increases.
Needle is too thick.
Needle is too thick.
Difference in level is large.
(it is 1.6 mm or more.)
– 52 –
Corrective measures
Polish the scratch using a fi ne
emery paper or the like.
Adjust the thread tension.
Bring up the looper near the
needle.
Readjust the clearance.
Tighten the thread tension.
Adjust the thread take-up thread
guide, right.
Stroke of thread take-up spring is
too small or too large.
Increase the height of the feed
dog.
Turn the needle bar and adjust so that
the sewing needle pierces the center
of loop on the right side of cloth.
Readjust the looper.
Readjust the spreader.
Polish the scratch using a fi ne
emery paper or the like.
Readjust the clearance.
Readjust the spreader.
Use a thick needle.
Adjust the thread tension.
Adjust the thread tension.
Adjust the thread take-up thread
guide, right.
Adjust the thread tension.
Adjust the thread take-up thread
guide, right.
Adjust the thread tension.
Replace the needle.
Handle the cloth so as to lightly
pull it in the rear on the left side.
Adjust the thread tension.
Lower the feed dog.
Decrease the stroke of the thread
take-up spring.
Reduce the change of thread
tension by reducing as few as
possible the threading portions
between thread stand, intermediate
thread guide and arm thread guide.
Make the needle as thin as
possible within the limits of the
possibility of sewing.
Make the needle as thin as possible within
the limits of the possibility of sewing.
Raise the feed dog.
Change the feed timing. (In this
case, please consult our dealers.)
Corresponding
item No.
10
16
16
16
10
12
11
14
16,18
17,18
16,18
17,18
7
10
10
12
10
12
10
7
10
14
11
8
7
7
14
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