Table of Contents
Advertisement
Trouble
① The needle is bent.
3. The needle often
breaks.
② The needle strikes the intermediate
③ The needle is too thin for the
④ The position of bird's nest
① The counter knife is dull.
4. Threads are not
trimmed.
② The difference in level between
③ The moving knife has been
④ The last stitch is skipped.
⑤ Bobbin thread tension is too low.
(Bobbin thread
only)
⑥ Flopping of cloth
① Timing between the needle and
5. Stitch skipping
often occurs.
② The needle is bent.
③ Length of needle thread remaining
① The needle thread tension is not
6. The needle thread
comes out on the
wrong side of the
② The tension release mechanism
material.
(Poorly tensed
③ The needle thread after thread
seam)
④ Number of stitches is too few.
⑤ The material is separated from
⑥ Thread slips off the tension
① Stitch skipping at the 1st stitch
7. Thread end of
the 1st stitch
② Needle used and thread used
comes out on the
right side of the
material.
③ Intermediate presser is not
Cause
presser foot.
material.
reducing mechanism is poorly
adjusted. As a result, the moving
knife interferes with the needle.
the needle hole guide and the
counter knife is not enough.
improperly positioned.
the hook is not correct. The
clearance provided between the
needle and the hook is too large.
after thread trimming is too long.
(In the case of stitch skipping
within the 2nd to 10th stitch from
the beginning of sewing)
high enough.
fails to work properly.
trimming is too long.
the throat plate. As a result, the
material sways and the thread is
pulled up.
controller.
are thick in terms of the inner
diameter of the intermediate
presser.
properly positioned in terms of the
needle.
Corrective measures
○ Replace the bent needle.
○ Correct the position of the intermediate
presser foot.
○ Replace it with a thicker needle according
to the material.
○ Adjust the position of moving knife before
it trims the thread. (1.1 ± 0.1 mm)
○ Replace the counter knife.
○ Increase the bend of the counter knife.
○ Correct the position of the moving knife.
○ Correct the timing between the needle
and the shuttle.
○ In crease the bobbin thread tension.
○ Lower the intermediate presser height of
the last stitch.
○ Correct the positions of the needle and
shuttle.
○ Replace the bent needle.
○ Reduce the thread take-up spring
pressure or increase the thread tension
applied by the thread tension controller
No. 1.
○ Increase the needle thread tension.
○ Check whether or not the tension disc No.
2 is released during bar-tracking.
○ Increase the tension of the thread tension
controller No. 1.
○ Decrease the tension of thread take-up
spring.
○ Turn OFF the thread clamp.
○ Use the concave type feed plate that
allows the material to come in close
contact with the throat plate.
○ Decrease the stroke of the intermediate
presser.
○ Increase the thread tension of the tension
controller No. 1.
○ Adjust the hook timing faster by a 1/2
stitch.
○ Increase the inner diameter of
intermediate presser.
○ Adjust the eccentricity between
intermediate presser and needle so
that needle enters in the center of
intermediate presser.
– 153 –
Page
18
24
136
136, 1 38
132
23
132
18
23,24
23
23
24
26
136
23
132
157
132
Advertisement
Table of Contents
