JUKI MEB-3200 Engineer's Manual page 121

Phenomenon
4. Stitch skipping near to top of eyelet
5. Seam splitting at the sewing end
6. Needle thread breakage
7. Looper thread breakage
8. Needle breakage
* When sewing heavy-weight materials
* When sewing heavy-weight materials with
cut-before knife
* Without needle thread clamp
9. Stitches at the straight section of the
buttonhole are not uniform.
Cause
4-1) The clearance between the presser foot and the needle
entry point is too llarge.
4-2) The cloth is flopping.
4-3) Needle thread loop is too large and falls. As a result, it is
not caught by the looper.
4-4) Needle thread loop cannot be made.
As a result, the looper cannot catch the thread
5-1) The feeding amount of needle thread is insufficient.
5-2) The timing of the right-hand looper is too late.
5-3) The opening amount of the right-hand spreader is
insufficient.
5-4) The gimp is too hard.
6-1) The needle thread tension is too high.
6-2) The needle comes in contact with the blade point of the
looper.
6-3) The thread paths in the needle, loopers, spreaders, throat
plate, etc. have become worn out or contain scratches.
6-4) The thread is too thick or too thin for the needle.
6-5) There are scratches in the needle holeor needle slot.
6-6) The needle size is not suitable fot the kind of throat plate.
7-1) The looper thread tension is too high.
7-2) The installing position of the left-hand spreader is
incorrect.
7-3) Refer to "5. Needle thread breakage" for details on other
causes and corrective measures.
8-1) The needle interferes with looper, spreader, etc.
8-2) The clearance between the needle and the looper varies
according to the turning angle (0˚, 90˚ and 180˚).
8-3) 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.
8-4) The height of the needle bar has been improperly
adjusted.
8-5) When the stitch bite width is narrowed, the needle guard
does not work on the outside needle side. (When
32040107 is used.)
8-6) The needle does not fit the kind of throat plate (needle
size used).
8-7) The needle bends at the thick section of the material
and stitch skipping occurs.
8-8) The needle bends at the cutting section of cloth cutting
knife and stitch skipping occurs.
8-9) Needle thread is depressed by the presser foot at the
start of sewing.
8-10) Material comes in contact with the needle tip after
sewing.
9-1) The left- and right-hand sewing pitches at the straight
section are different from each other.
9-2) The left- and right-hand positions at the straight section
are different from each other.
9-3) Stitches which should be parallel are slant.
9-4) The rear face side (indented part) of needle comes in
contact with the slot of throat plate, or it is near the slot.
117
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1 Approach the presser foot. (Adjust the lateral position.)
2 Approach the opening position of presser plate to the
throat plate. (Adjust the cloth open.)
1 Decrease the sewing speed of eyelet section.
2 Correct the presser foot or replace it with a new one.
3 Tilt the presser foot to the inside. (Adjustment)
4 In case of eyelet, use the presser and holding plate for
eyelet.
• Lift the installing position of thread take-up thread guide 5.
• Decrease the needle thread tension. Lower the installing
position of thread take-up thread guide 3.
• 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.
• Use a throat plate suitable for the needle size.
• Adjust the sewing conditions to obtain an appropriate thread
tension.
• Check and adjust the installing position.
• Adjust the clearance between the looper and the needle
properly. Adjust the timing to open/close the spreaders
properly.
• Adjust the center of the needle.
• Check and adjust the clearance.
• Check and adjust the height of the needle bar.
• Use the Rev.Up part (32040115).
• Use the throat plate suitable for the needle.
• Change the needle to a thicker one. Adjust the stitch base
line offset.
• Change the needle to a thicker one. Properly adjust the
inside needle entry to the inside of cutting section.
1 Increase the feeding amount of needle thread.
2 Decrese the needle thread tension at the time of stop.
(ROM007* only)
3 Use the needle thread clamp.
1 Lower the finger guard to sew.
2 Lower the height of the presser. (Adjustment)
3 Use the machine by combining the front set function with
memory switch No. 23 (presser down).
• Compensate the length by lengthwise compensation of left
parallel section of the data compensation.
• Compensate the position by lengthwise compensation of
left eyelet of the data compensation.
• Compensate the inclination by turning compensation of
parallel section of the data compensation.
1 Adjust the center of the needle.
2 Perform additional work on the throat plate.
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Corrective measure