–57 –
Troubles
Causes
Checking
Corrective measures
Needle thread is not
caught.
Bobbin thread is not
caught.
Tension of the bobbin
thread is too high.
Knife pressure of the
waiting knife is too high.
Thread is not cut sharply.
Presser foot drops from
cloth at the time of thread
trimming.
Stitch skipping at the last
stitch.
Most advanced position
of the moving knife is not
obtained.
Top end of the moving
knife is broken or has
burrs.
Most advanced position
of the moving knife is not
obtained.
Check the routing of bobbin
thread.
Top end of the moving knife
has broken or been
scratched.
Check the height of moving
knife.
Presser foot drops from
cloth at the time of thread
trimming.
Adjust the tension of bobbin
thread.
Refer to "(18) -3) Knife pressure".
Refer to Causes “Thread cannot
be trimmed” and “Thread remains
uncut after trimming”.
Perform thread trimming on cloth.
Refer to “(7) Needle-to-hook
timing”
Refer to "(16) Reverse feed
c y l i n d e r a n d c o n d e n s a t i o n
cylinder".
Refer to "(18) -5) Most advanced
position of the moving knife".
Replace the moving knife with a
new one.
Refer to "(18) -5) Most advanced
position of the moving knife".
Correctly thread bobbin thread.
Replace the moving knife with a
new one.
Adjust the height of moving knife.
Perform thread trimming on cloth.
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