Mitsubishi PLK-E1008H, Technical Manual

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8. BAD SEWING CONDITION & ITS CAUSE AND REMEDY
[NOTE] Please fix the troubles during the sewing machine operation with referring to the
following instructions.
Beside, if the trouble conditions are not coming under these classification, please
contact the sewing machine dealers nearby.
Bad condition Cause Remedy
Ref. page
& Item
Poor thread quality Use better quality thread ----
Tight upper thread tension Adjust thread tension 6-6
Strong thread take up spring
Adjust thread take up spring
properly
7-13
Upper thread is thicker than
needle size
Change needle to suitable size ----
Damages on shuttle hook or
driver
Change them new ones or grind
them with buffing wheel or grind
stone
----
Damages inside presser foot
needle hole Change it new one or grind it with
buffing wheel
----
Needle touches with presser
foot needle hole
Move presser foot position 7-7
Needle and shuttle hook are
not in proper timing
Adjust the timing 7-2
Slow down sewing speed 6-5
1.
Upper thread
breakage often
happens
Thread melts with needle
heat
Use silicon oil ----
Thread tension discs are not
opened at trimming
Adjust thread tension release 7-8
Thread take up spring swing
is too much Adjust thread take up spring’s
swing stroke
7-13
Needle size is bigger than
thread size
Change needle to suitable size ----
Needle and shuttle hook are
in bad timing
Adjust the timing properly 7-2
Adjust wiper cylinder position 7-9-3
Adjust thread puller stroke 7-9-1
Adjust upper heater position 7-9-4
Thread tail from needle is
very short after trimming
Adjust adjusting plate position 7-13
2.
Upper thread is
pulled out from
needle
Bobbin thread tension is too
tight Loosen bobbin thread tension
spring
6-6
Thread take up spring swing
is too small Adjust thread take up spring’s
swing stroke
7-13
Adjust wiper cylinder position 7-9-3
Adjust thread puller stroke 7-9-1
Trimmer equipment position
is not correct
Adjust upper heater position 7-9-4
3.
Thread tail from
needle is too
long after
trimming
Bobbin thread tension is too
loose Loosen bobbin thread tension
spring 6-6
7-13
Trimmer function is canceled Resume trimmer function
Control
unit
Trimmer switch is off Put on the trimmer switch 6-4
Heater knife is aging Change the heater knife 7-9,10
Skip stitching happens at
trimming
Adjust synchronizer position 7-14
4.
Trimming is not
functioned
Preheating time is short Adjust the preheating time 6-3
Bad condition Cause Remedy Ref. Page
5. The hook position is deviated Set the needle stop position to the 5-5
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