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Cause (1)
Troubles
Cause (2)
Corrective measures
From the previous page
4. Needle breakage
3-2) Thread tension components
3-3) Influence of heat
3-4) Thread path components
3-5) Position of needle is
improper.
3-6) Setting of needle cooler is
improper.
3-7) Needle is improper
4-1) Position of needle is
improper.
4-2) Hemming binder components
4-3) Thread tension components
2)-A Needle thread tension is
too high (excessively
tightened).
2)-B Tension of thread tension
No. 1 is too low.
3)-A Damage of thread due to
heat
4)-A Threading is wrong.
4)-B Finish of thread path is
improper.
5)-A Height of the needle bar
is improper.
6)-A Air pressure of needle
cooler is too high.
6)-B Direction of air blow is
improper.
7)-A Installation of needle is
improper. (Direction and
insertion are improper.)
1)-A Lateral position of needle
and needle hole of throat
plate is improper.
1)-B Lateral position of needle
and needle hole of
presser foot is improper.
2)-A Edge of fold of hemming
is sewn.
2)-B Sewing is performed in
the state that hemming is
rolled in more than three
folds.
2)-C Sewing quality of the
previous process
(especially, lapping
seam) is inferior.
3)-A Needle thread tension is
too high.
Decrease the tension.
Adjust the tension to such an extent that
thread between thread tensions No. 1 and
No. 2 does not move roughly.
(However, when the tension of thread
tension No. 1 is excessively high, thread
trimming performance is affected. Do not
excessively increase the tension.)
Increase oil amount in the hook.
When sewing at 4,000 rpm or more, install
the needle cooler.
Check the threading according to the
Instruction Manual.
Check the finish of each thread path and
correct with buff when it is improper.
Adjust the height of needle bar according
to 4-(1).
Making as the base the adjustment
procedure described in the Instruction
Manual, in accordance with the conditions
of cloth and thread, perform fine
adjustment according to 4-(21).
• When setting the needle bar
somewhat in the lower position, be
careful of needle thread lock between
needle and needle guard section of
inner hook at the lower dead point of
needle bar.
• When setting the needle bar somewhat
in the upper position, be careful of the
contact of the blade point of hook with
the belly section of needle.
Set the air pressure to the proper one (as
low as possible) according to the
Instruction Manual.
When the air pressure is too high, needle
thread becomes unstable and inferior
product is apt to occur.
Adjust the direction of air blow according
to the Instruction Manual.
Install needle again
Adjust the lateral position of the needle.
Loosen the presser bar bracket and correct
the lateral position of the presser.
It is the aim that the center of needle in
terms of the center of needle hole of the
presser foot is slightly located to the right
side.
Properly correct the lateral position of the
binder.
Adjust by handling so that correct hemming
is performed. (When cloth becomes thicker
than necessary due to inferior rolling,
needle breakage is apt to occur.)
Check the rolled condition of the previous
process.
(When cloth becomes thicker than
necessary due to inferior rolling of the
previous process, needle breakage is apt
to occur.
Decrease the tension.
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