Troubles And Corrective Measures In Sewing - JUKI MEB-3200 Manuel D'utilisation

13. TROUBLES AND CORRECTIVE MEASURES IN SEWING

Phenomenon
1. Sttch skppng
• When changng needle sze
• W h e n k  n d o f t h r e a d  s
affected
• When sewng heavy-weght
materals
2. Sttch skppng at the sewng
start
3. Sttch skppng at eyelet secton
4. Seam splttng at the sewng
end
5. Needle thread breakage

Cause
• The needle s bent. There s a scratchon the
needle. The needle s ncorrectly attached.
• Knd of needle s wrong.
• The clearance between the needle and the
looper s too large.
• The clearance between the needle and the needle
guard s too large or the needle and the needle
guard come n excessve contact wth each other.
• The clearance between the needle and the
looper varies according to the turning angle (0˚,
90˚ and 180˚).
• Improper adjustment of the tmng between the
needle and the looper
• Improper adjustment of the tmng to open/close
the spreader The spreader comes n contact wth
the needle.
• Moton to open/close the spreader s not smooth.
• The clearance between the presser foot and the
needle entry pont s too large.
• Thread tenson s not proper.
• The blade pont of looper has worn out.
• Improper adjustment of the heght of the needle bar
• The looper or the spreader not sutable for the
sttch bte wdth s used.
• Improper adjustment of the clearance between
the needle and the looper
• Improper adjustment of the tmng to open/close
the spreader The spreader comes n contact wth
the needle.
• The needle does not fit the kind of throat plate
(needle sze used).
• Thread which is difficult to make loops is used.
(Hard-to-slde thread or the lke)
• The needle s bent at the thck secton of the
materal and sttch skppng occurs.
• In case of the cut-before knfe, the nsde needle s
bent at the cuttng secton and sttch skppng occurs.
• The length of remanng needle thread at the
start of sewng s too short.
• The left-hand spreader s nstalled ncorrectly.
• The tmng of the rght-hand looper s too early.
• The clearance between the presser foot and the
needle entry pont s too large.
• The looper s bent. There are scratches on the looper.
• Feeding amount of the needle thread is insufficient.
• Looper thread clamp/looper thread presser s
weak and the looper thread comes off at the
start of sewng.
• The clearance between the presser foot and the
needle entry pont s too llarge.
• The cloth is flopping.
• Needle thread loop s too large and falls.
As a result, t s not caught by the looper.
• Needle thread loop cannot be made.
As a result, the looper cannot catch the thread
• The feeding amount of needle thread is insufficient.
• The tmng of the rght-hand looper s too late.
• The openng amount of the rght-hand spreader
is insufficient.
• The gmp s too hard.
• The needle thread tenson s too hgh.
• The needle comes n contact wth the blade pont
of the looper.
• The thread paths n the needle, loopers,
spreaders, throat plate, etc. have become worn
out or contan scratches.
• The thread s too thck or too thn for the needle.
• There are scratches n the needle holeor needle slot.
Corrective measure
• Check and replace the needle.
• Use DO x 558 needle.
• Adjust the clearance at the tme of nsde needle or
outsde needle.
• Check and adjust the clearance.
• Adjust the center of the needle.
• Adjust the tmng wth the sttch bte wdth used.
• Adjust the tmng to open/close the spreader by the
sttch bte wdth used.
• Remove the cloth waste from the spreader. Replace the
spreader wth a new one.
• Check the clearance and properly adjust t.
• Set the thread tenson to the proper value.
• Correct the looper wth ol-stone or the lke, or replace t
wth a new one.
• Check and adjust the heght of the needle bar.
• Replace the looper or the spreader wth a new one
sutable for the sttch bte wdth.
• Adjust the clearance at the tme of nsde needle or
outsde needle wth the needle sze used.
• Adjust the tmng to open/close the spreader wth the
needle sze used.
• Use the throat plate sutable for the needle.
• Decrease the needle thread tenson. Lower the nstallng
poston of thread take-up thread gude 3 .
• Decrease the number of revoluton of the sewng machne.
• Change the needle to a thcker one. Adjust the sttch
base lne offset.
• Re-set the cut space.
• Decrease the needle thread tenson at the tme of
thread trmmng.
• Check the nstallng poston and adjust t.
• Check the tmng between the needle and the looper,
and adjust t.
• Check the clearance and adjust t.
• Check the looper and replace t wth a new one.
• Adjust the feedng amount of needle thread
• Check and adjust the pressure.
• Check the clearance and adjust t properly.
• Decrease the sewng speed of eyelet secton.
Correct the presser foot or replace t wth a new one.
• Lft the nstallng poston of thread take-up thread gude 5 .
• Decrease the needle thread tenson. Lower the nstallng
poston of thread take-up thread gude 6 .
• Adjust the feedng amount of needle thread.
• Check and adjust the tmng between the needle and the looper.
• Check and adjust the openng amount of the spreader.
• Replace the gmp. Check the thread path of gmp.
• Adjust the sewng condtons to obtan an approprate
thread tenson.
• Check and adjust the clearance.
• Check and replace the respectve parts.
• Replace the needle wth a proper one.
• Check and replace the needle.
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