JUKI MO-6000G Series Engineer's Manual page 87

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I
Trouble
12. Problems with double chain stitch chain-off
thread.
Case (1)
Adjustment of loopers
Needle
Guard
Position of the throat plate
Throat plate
Presser foot
M11ln feed dog
Double hooking
Thread tension
Case(2)
Adjustment of the loopers for producing chain-off thread
without materials requires higher accuracy.
The needle guard (C) is
too
high, damaging loops.
The needle comes Into contact with the Iron! edge ol
the needle hole In the throat plate.
Tho lateral position of the throat plate with respect to
the teed dogs Is wrong, causing chain-off to drop In.
j
A
dent exists on the flat part between the rear edge of
the needle hole and feed dog groove.
=:,Oc::::c
l:.
Dent
The rear pressure foot is indented and not flush with
the presser foot sole, so that it cannot hold chain-off
thre11d.
The leadlng edge ol the main feed dog Is too sharp and
cuts chaln•olf thread.
The needle thread 1s not drawn up fully because of the
Insufficient return of the double chain looper or wrong
threading.
If the feed pllch Is too small. the cam timing will be
advanced.
The needle Is bend or chain-odd thread runs back due
to excessive needle thread tension.
Both the needle thread and looper thread tension are
too low.
Check and Corrective measures
Refer to the related Standard Adjustment.
Refer to the related Standard Adjustment.
Correctly posrllon the throa1 plate.
Repair or replace the throat plate, since sueh dent causes
chain-off thread to s6p out.
Replace ii, or correct ii to make
II
flush with
Ille
presser
foot sole.
Buff the leading edge of the main feed dog.
Reier to the related Standard Adjustment for the ,eturn of
the double chain looper. See lhe lh1eadlng digram for
correct threading.
Aelard the cam timing.
Reduce the needle thread tension.
Slightly Increase the both tensions.
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