JUKI MO-6000G Series Engineer's Manual page 86

Trouble
10. Triangle double chain needle thread stitches
are skipped.
The needle falls to catch the needle thread
loop on the double chain looper, resulting In
the stitch skipping shown below.
~ /
Defectively inter1aced loop
k
Neadleth'1
~ • needle thread axtendu
lo the adjacent stitch.
Case (1)
Double chain looper
Adjustment of looper
Thread tension
Stitch length
Needle guard
Double-chain stitch needle thread guide.
11. Overlocking chain-on thread Is bad. Position of the throat plate
(
Provided that no chain-off trouble occurred ]
when sewing operation was done with
materials set on the machine.
Feed dog
Adjustment of looper
· Thread lension
Case(2)
The chain looper Is too high and too close to the throat
plate, or has bad shapo.
The return is not enough, causing lhe needle to miss
the loop.
The needle thread tension is too low.
The sUtch length Is as small as 1.5 mm or Jess.
A needle guaro Is too high, and catches needle thread
loops.
The needle thread guide is Installed loo high, and it fails
to tense the thread.
The lhroat plate has been improperly positioned
longitudinally, and chain-off thread gets in between lhe
· main feed dog and throat plate, causing defective Chain-
off thread.
The auxmary feed
dog
has scratch.
The auxiliary feed dog Is too high, and Interferes with
chain-off thread. The auxlllary feed dog is too low.
(Lower than the main feed dog t,y more than
o.s
mm)
Adjustment ol loopers for producing chaln-oll thread
without materials requires higher accuracy.
The thread tension is too low.
The needle thread tension
is
too high, causing damaged
balance with other thread tension
Check and Corrective measures
Correct the height of the chain looper by pushing It down
until it cones Into contact with the stopper. Replace the
chain looper having a bad shape.
Refer 10 the related Standard AdjustmenL
Slightly increase the needle thread tension.
Slightly increase the Stitch length.
Adjustment of loopers for producing chain-off thread
without materials requires higher accuracy lhan that with
materials.
Refer
10
the related Standard Adjustment.
Refer to the related Standard Adjustment.
Correctly position the throat plate.
Repair or replace the auxlliary feed dog.
Refer lo lhe pertinent Standard Adjuslment.
Re1er to the related Standard Adjustment.
SlighUy increase the tension.
Check whether the needle thread take-up guide or needle
thread guide Is posllioned too high with consequent
excessive needle thread tension. And ii so, correct it.
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