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Trouble
12. The bird's nest at the start of sew-
ing is big.
13. The situation of crossing over the
multi-layered section of the mate-
rial is imperfect.
14. Needle thread breakage at the
start of sewing
15. Faulty thread trimming (The nee-
dle and bobbin threads are not
trimmed.)
Cause (1)
12-1) The remaining length of
needle thread after a thread
trimming is long.
13-1) The height of a feed dog is
low.
14-1) The needle thread presser
device is put on.
15-1) Wear of the cutting portion
of a thread trimming knife or
loop spreading knife
15-2) The amount of engagement
between their cutting portions
is insufficient.
Cause (2)
1-A) Thread is cut by the needle
thread caught under the press-
er and because needle thread
presser device is put on.
Check and corrective measures
By strengthening the first thread tension, short-
en the remaining length of needle thread after
a thread trimming.
Lengthen the pitch of one needle at the start of
sewing to make the needle thread to be tucked
under the presser.
For example, make a reverse stitch to be a
condensed stitch and set the number of nee-
dles to one needle in order to enlarge a pitch.
At the time of passing over the multi-layered
section of the material, raise a feed dog with
the custom switch.
The needle thread is made easy to pass
through by losing the presser.
P161 is changed from 0 to 1, the presser at
the start is slightly lifted to facilitate removal of
needle thread. (P165: Presser lifting operation
time is set to 20 or more when the thread is
held.)
It is replaced by a new knife.
The amount of engagement between them is
adjusted with an eccentric pin.
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