JUKI SC-956, Инструкция по эксплуатации

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Phenomenon Cause Corrective measures
2. Stitch skipping
①
Clearance between the needle and the
hook blade point is too great.
◦
Refer to " 8-1. Needle-to-hook relation" p.105 .
② Timing between the needle and the
hook is excessively advanced or
retarded.
◦ Refer to "8-1. Needle-to-hook relation" p.105 .
③ Pressure of the presser foot is too low. ◦ Tighten the presser spring regulator.
④
When the needle thread slips out of the
rotary disc.
◦
Refer to "8-1. Needle-to-hook relation" p.105 .
⑤ Improper type of needle is used. ◦ Replace the needle with one which is thicker than
the current needle by one count.
⑥ Synthetic thread or thin thread is used. ◦ Wind the thread on the needle.
⑦
Stitch skipping occurs at the beginning
of sewing.
◦
Use the optional needle clamp wire.
◦ Run the sewing machine under the soft start mode
by 2 to 3 stitches from the sewing start.
⑧ Stitch skips when sewing multilayered
parts of the material. ◦ Use the needle thread guide and precisely adjust
the hook timing.
⑨ Stitch skipping occurs when the materi-
al thickness changes, i.e., from a two-
ply part to a multi-layered part and vice
versa. ◦ Move the presser foot toward the operator.
At this time, be careful not to allow the presser foot
to come in contact with the needle.
3. Loose stitches ① Bobbin thread does not pass through
the forked end of the tension spring on
the bobbin case. ◦ Thread the bobbin case correctly.
② Thread path has rough surface. ◦ Remove rough parts with a fine emery paper or
buff it up.
③ Bobbin fails to move smoothly. ◦ Replace the bobbin or hook with a new one.
④ Bobbin case opening lever provides
too much clearance at the bobbin. ◦ Refer to "8-4. Adjusting the bobbin case
opening lever" p.110
.
⑤ Bobbin thread tension is too low. ◦ Adjust the bobbin thread tension.
⑥ Bobbin has been wound too tightly. ◦ Decrease the tension applied to the bobbin winder.
⑦ The presser foot does not securely
press the multi-layered section of the
material. ◦ Change presser foot with the hinging presser
(B1524512FBE).
(The presser foot with large front and rear
elevation angles is pRefer to rable.)
◦ Retard the hook timing by 2 to 3 degrees.
⑧ Needle eyelet is too small for thickness
of thread, preventing smooth take-up
motion of the thread take-up lever. ◦ Use the needle thread take-up eyelet.
⑨ With respect to tensing of thick
thread, neither needle thread tension
nor bobbin thread tension can be
increased, resulting in production of
isolated idling loops. ◦ Use the needle thread presser.
◦ Use the bobbin thread tension spring t0.3 (2261
2808).
⑩ Isolated idling loops are produced
during the reverse feed stitching. ◦ Retard the hook timing.