Troubles And Corrective Measures In Br - JUKI LK-1903B Instruction Manual

VII. TROUBLES AND CORRECTIVE MEASURES IN BR
Trouble
(Phenomenon)
1. Thread slips off ① Lenght of needle thread remaining
the needle at
the sewing start.
Or, the machine ② The material flops.
starts sewing a
button from an
intermediate step ③ The wiper does not press the thread.
of button sewing ④ Sewing machine speed is too fast at
procedure.
① The needle hits the edge of holes in
2. Needle breakage
frequently occurs.
② The boss of the needle hole guide
③ The needle used is too thin.
① Length of needle thread remaining
3. The finished state
of the wrong side
of the material is
② The thread catching force of the
extremely poor.
③ If sewing a button of which wrong
① The button is not secured in the
4. The button is not
sewn at the correct
position.
② The leaf spring of the button clamp
③ When using a button of which wrong
Cause
in the needle is too short.
the start of sewing.
the button.
comes in contact with the recessed
part of the feed plate.
in the needle is too long.
wiper is excessive.
side is round-shaped, the stitches
on the wrong side of the material are
entangled to make a lump of thread.
correct sewing position.
excessively works.
side is round-shaped, the thread
e n t e r s t h e s p a c e b e t w e e n t h e
bottom face of the button and the
top face of the boss of the needle
hole guide. As a result, the button is
not fed smoothly.
• Decrease the tension of the tension controller No. 1.
• Adjust the disk floating amount of the tension controller
No. 2.
• Use a needle hole guide with a higher boss.
• Use a button clamp of which lever plate is thinner than
the current one.
• Correct the wiper spring.
• Increase the number of stitches of the soft-start (memory
switch).
(Example : 400 → 400 → 400 → 900 → )
• Adjust the position of the button clamp jaw lever so that
the needle enters the exact center of the holes in the
button.
• Adjust the position of the feed plate so that it does
not come in contact with the boss of the needle hole
guide. If the sewing size is large for the feed plate used,
replace it with the feed plate for medium-size buttons or
for large buttons.
• Change the needle count in accordance with the sewing
product or the holes in the button.
• Increase the tension of the tension controller No. 1.
• Adjust the disk floating timing of the tension controller
No. 2.
• Decrease the pressure of the wiper spring.
• Replace the current button clamp with another one of
which lever plate is thicker than the current one.
• Improve the actuation of the button clamp.
• Correct the button clamp jaw lever spring so that it
increases the retaining force for the button.
• Correct the leaf spring so that it does not excessively
work.
• Replace the current button clamp with another one of
which lever plate is thicker than the current one.
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Corrective measures