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

13. TROUBLES AND CORRECTIVE MEASURES IN SEWING

Phenomenon
1. Stitch skipping
• When changing needle size
• W h e n k i n d o f t h r e a d i s
affected
• When sewing heavy-weight
materials
2. Stitch skipping at the sewing
start
3. Stitch skipping at eyelet section
4. Seam splitting at the sewing
end
5. Needle thread breakage
66
Cause
• The needle is bent. There is a scratchon the
needle. The needle is incorrectly attached.
• Kind of needle is wrong.
• The clearance between the needle and the
looper is too large.
• The clearance between the needle and the needle
guard is too large or the needle and the needle
guard come in excessive contact with each other.
• The clearance between the needle and the
looper varies according to the turning angle (0˚,
90˚ and 180˚).
• Improper adjustment of the timing between the
needle and the looper
• Improper adjustment of the timing to open/close
the spreader The spreader comes in contact with
the needle.
• Motion to open/close the spreader is not smooth.
• The clearance between the presser foot and the
needle entry point is too large.
• Thread tension is not proper.
• The blade point of looper has worn out.
• Improper adjustment of the height of the needle bar
• The looper or the spreader not suitable for the
stitch bite width is used.
• Improper adjustment of the clearance between
the needle and the looper
• Improper adjustment of the timing to open/close
the spreader The spreader comes in contact with
the needle.
• The needle does not fit the kind of throat plate
(needle size used).
• Thread which is difficult to make loops is used.
(Hard-to-slide thread or the like)
• The needle is bent at the thick section of the
material and stitch skipping occurs.
• In case of the cut-before knife, the inside needle is
bent at the cutting section and stitch skipping occurs.
• The length of remaining needle thread at the
start of sewing is too short.
• The left-hand spreader is installed incorrectly.
• The timing of the right-hand looper is too early.
• The clearance between the presser foot and the
needle entry point is too large.
• The looper is bent. There are scratches on the looper.
• Feeding amount of the needle thread is insufficient.
• Looper thread clamp/looper thread presser is
weak and the looper thread comes off at the
start of sewing.
• The clearance between the presser foot and the
needle entry point is too llarge.
• The cloth is flopping.
• Needle thread loop is too large and falls.
As a result, it is 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 timing of the right-hand looper is too late.
• The opening amount of the right-hand spreader
is insufficient.
• The gimp is too hard.
• The needle thread tension is too high.
• The needle comes in contact with the blade point
of the looper.
• The thread paths in the needle, loopers,
spreaders, throat plate, etc. have become worn
out or contain scratches.
• The thread is too thick or too thin for the needle.
• There are scratches in the needle holeor needle slot.
Corrective measure
• Check and replace the needle.
• Use DO x 558 needle.
• Adjust the clearance at the time of inside needle or
outside needle.
• Check and adjust the clearance.
• Adjust the center of the needle.
• Adjust the timing with the stitch bite width used.
• Adjust the timing to open/close the spreader by the
stitch bite width used.
• Remove the cloth waste from the spreader. Replace the
spreader with a new one.
• Check the clearance and properly adjust it.
• Set the thread tension to the proper value.
• Correct the looper with oil-stone or the like, or replace it
with a new one.
• Check and adjust the height of the needle bar.
• Replace the looper or the spreader with a new one
suitable for the stitch bite width.
• Adjust the clearance at the time of inside needle or
outside needle with the needle size used.
• Adjust the timing to open/close the spreader with the
needle size used.
• Use the throat plate suitable for the needle.
• Decrease the needle thread tension. Lower the installing
position of thread take-up thread guide
• Decrease the number of revolution of the sewing machine.
• Change the needle to a thicker one. Adjust the stitch
base line offset.
• Re-set the cut space.
• Decrease the needle thread tension at the time of
thread trimming.
• Check the installing position and adjust it.
• Check the timing between the needle and the looper,
and adjust it.
• Check the clearance and adjust it.
• Check the looper and replace it with a new one.
• Adjust the feeding amount of needle thread
• Check and adjust the pressure.
• Check the clearance and adjust it properly.
• Decrease the sewing speed of eyelet section.
Correct the presser foot or replace it with a new one.
• Lift the installing position of thread take-up thread guide
• Decrease the needle thread tension. Lower the installing
position of thread take-up thread guide
• Adjust the feeding amount of needle thread.
• Check and adjust the timing between the needle and the looper.
• Check and adjust the opening amount of the spreader.
• Replace the gimp. Check the thread path of gimp.
• Adjust the sewing conditions to obtain an appropriate
thread tension.
• Check and adjust the clearance.
• Check and replace the respective parts.
• Replace the needle with a proper one.
• Check and replace the needle.
Page
9
9
47
47
-
45
49
49
30,50
16,40
45
45
45,64
47
49
w61
16,31
.
24,25
9
23,33,37
31,40
48
45
30,50
45
31
52
30,50
25
50
31
.
16、
.
31、40
31
45
49
12、32
16、31
47
9、47、48
9
9