－
7
－
Phenomenon
cause
corrective measure
4. The tread slps off the
needle upon beng
trmmed.
1
The returnng force of the thread
take-up sprng s too hgh.
2
The tenson of the tenson controller
No. s too hgh.
3
The counter knfe s mproperly pos-
toned.
○
○
the counter knife and the knife
thread guide" p.111
5. The needle thread
cannot be trmmed.
(The bobbn thread
can be trmmed.)
1
The last sttch has been skpped.
(The clearance between the needle
and the hook s too large.)
○
6. Bobbn thread cannot
be trmmed.
(Needle thread can be
trmmed.)
1
The movng knfe fals to catch the
bobbn thread at the last sttch.
(The sttchng ptch of the last sttch
s excessvely large, and the bobbn
thread s not present on the movng
knfe locus.)
○
Decrease the sttchng ptch of the
last sttch. (To approxmately 2
mm)
7. Nether the needle
thread nor the bobbn
thread can be trmmed.
1
The thread trmmng tmng s wrong.
2
The knfe has been damaged.
3
The knfe pressure s nadequate.
4
The movng amount of the movng
knfe s too short.
5
Pattern nput falure
○
Replace the knfe.
○
Increase the knfe pressure.
○
It s necessary to check the thread
trmmng motor operaton.
○
Input the pattern pror to thread
trmmng usng the forward sttch.
8. Thread cannot be
trmmed sharply
1
Thread trmmng tmng s wrong.
2
The knfe pressure s too low.
3
The knfe blade s blunt.
○
the counter knife and the knife
thread guide" p.111
○
Increase the knfe pressure.
○
Replace the knfe.
9. The machne cannot
be powered on.
1
Emergency swtch s n the ON
state.
○
