JUKI DDL-8000A, Руководство инженера

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Trouble Cause (1) Cause (2) Check and corrective measures
From the previous page
2-3) The needle thread slips
off the needle immediate-
ly after thread trimming.
3-A) Too early cam timing or too late hook
timing causes the moving knife to cut
the needle thread to hold 3 threads
before thread separation.
Slipping of the needle thread from the needle immedi-
ately after thread trimming results from cutting the nee-
dle thread passing though the needle due to defective
thread spreading by the moving knife. In such a case,
Thread chips of 40 mm level exist under the throat
plate or on the underside cover. In this case, delay the
timing of the thread trimming cam.
2-4) Knot tying between the
needle and bobbin threads
is not easy at sewing start.
4-A) The sewing speed at sewing start is
too fast to knot the needle and bobbin
threads together.
Conduct 1 or 2 stitches of soft-start (800 sti/min) at the
sewing start.
3. The thread tension is
inappropriate at sewing
start.
3-1) The tension of the needle
thread is too low at sew-
ing start.
1-A) Bobbin idling causes the bobbin thread
tension at sewing start to decrease.
Adjust the hook thread presser in accordance with 3.-
(9)-7.
1-B) The tensions of the bobbin thread and
needle thread are too low.
Increase the tensions of the bobbin thread and needle
thread.
1-C) The presser or throat plate is inappro-
priate.
Refer to the previous item, [An inappropriate needle,
throat plate, or presser is used. Alternatively, he pres-
sure of the presser is too low].
4. The needle thread is un-
trimmed. (But the bobbin
thread is trimmed.)
4-1) Stitch skipping at the final
stitch occurs.
1-A) The needle is inappropriately mount-
ed.
Mount a needle appropriately and make sure that the
needle is not bent.
1-B) The stroke of the thread take-up spring
is too long.
Shorten the stroke of the thread take-up spring. (5 to 7
mm)
1-C) The hook is inappropriately adjusted. Check for stitch skipping at low sewing speed, and re-
adjust the hook timing (Hasten the timing of the hook.).
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