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4. TROUBLES AND CORRECTIVE MEASURES
Troubles
Causes
Correctve measures
Page
1. Needle thread break-
age
1. Thread tenson at parallel secton
s too hgh.
2. Pressure or stroke of thread take-
up sprng s too large.
3. There s a burr or scratch on the
blade pont of hook.
4. Hook tmng s not proper.
5. There s a scratch on the thread
path.
6. Attachng needle s wrong.
7. Needle s too thn.
8. Needle tp s damaged.
™
Decrease the thread tenson at paral-
lel secton.
™
Decrease the tenson of thread take-
up sprng or decrease ts stroke.
™
Buff the blade pont of hook. Or, re-
place the hook.
™
Adjust agan the hook tmng wth tm-
ng gauge.
™
Polsh the thread path wth sand pa-
per and buff t.
™
Adjust agan the drecton, heght,
etc.
™
Replace the needle wth a thcker one.
™
Replace the needle.
p.59
p.90
p.88
p.30
p.30
p.30
2. Needle thread slps
off.
1. Needle thread trmmer opens too
early.
2. Whp sttchng s not formed at the
start of sewng. (Tenson at the
start of sewng s too hgh.)
3. Threadng needle thread s wrong.
4. Speed at the start of sewng s too
fast.
™
Delay the openng tmng of the nee-
dle thread trmmer.
™
Decrease tenson at the start of sew-
ng. (Sewng data
)
™
Thread properly agan.
™
Set the soft-start functon. (Memory
swtch data
to
)
p.89
p.63
p.30
p.77
3. Wobblng at parallel
secton
1. Thread tenson at parallel secton
s too low.
2. Bobbn thread tenson s too hgh.
3. Pre-tenson s too low.
™
Increase the thread tenson at paral-
lel secton.
™
Decresase bobbn thread tenson.
(Purl sttchng : 0.05 to 0.1N )
™
Increase pre-tenson.
p.59
p.31
4. Wobblng at the start
of sewng
1. Thread tenson at parallel secton
s too low.
2. Poston of needle thread trmmer
s too hgh.
3. Stroke of thread take-up sprng s
too large.
™
Increase the thread tenson at paral-
lel secton.
™
Lower the needle thread trmmer to
such an extent that t does not come
n contact wth the presser.
™
Decrease the stroke of thread take-
up sprng.
p.59
p.89
p.90
5. Needle thread ap-
pears on the wrong
sde of materal at
bar-tackng secton
n dumplng cond-
ton.
1. Bar-tackng thread tenson s too
low.
2. Bobbn thread tenson s too hgh.
3. Number of sttches of radal shape
s too many.
4. Tenson at the end of sewng s too
low.
™
Increase the bar-tackng thread ten-
son.
™
Decresase the bobbn thread tenson.
(0.05 to 0.1N )
™
Decrease the number of sttches.
(Sewng data
)
™
Increase tenson at the end of sew-
ng. (Memory swtch data
)
p.59
p.31
p.76
p.77
6. Stitches float.
1. Bobbn thread tenson s too low.
2. Bobbn thread comes off bobbn
case.
™
Increase the bobbn thread tenson.
™
Perform proper threadng the bobbn
case.
™
Take care that the wndng amount of
bobbn thread s not excessve
p.31
p.31
p.50
7. Sttch skppng
1. Button hole s small n terms of the
sze of presser.
2. Materal flops because of lght-
weght.
3. Attachng needle s wrong.
4. Needle s bent.
5. There s a burr or scratch on the
blade pont of hook.
™
Replace the presser wth a smaller
one.
™
Delay the hook-to-needle tmng.
(Lower the needle bar by 0.5 mm.)
™
Adjust agan the drecton, heght,
etc.
™
Replace the needle.
™
Buff the blade top of hook. Or, re-
place the hook.
p.88
p.30
p.30
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