JUKI DDL-9000C-S Series - Uneven Material Feed Troubleshooting (Continued); High Sewing Speed Issues

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Trouble Cause (1) Cause (2) Check and corrective measures
From the previous page
2-2) Pressing is inappropriate. 2-A) The pressure is too high. Minimize the pressure. For some materials,
sewing with the presser slightly oated with the
adjustable screw of the minute presser lifter is
effective.
2-B) The nish of the backside of the
presser is rough.
Buff the sole.
2-C) The presser is made from Non-
smooth material.
Use a uorocarbon resin presser or a special
processed presser.
2-3) The sewing speed is too high. Reduce the sewing speed.
3. “Balloon” stitches (loose stitches
and looping)
Thread knots are formed on ei-
ther side of material as a random
thread loop.
3-1) The thread tension is too low. Increase the 2nd thread tension.
3-2) The thread take-up spring is
inappropriately adjusted.
2-A) The stroke of the thread take-
up spring is too short.
The thread take-up spring with too short stroke
cannot sufciently take up the loosened thread
resulting in a higher possibility of balloon
stitches or thread breakage. The thread take-
up spring with too low tension cannot function
well at high speeds or sufciently take up the
thread resulting in a higher possibility of bal-
loon stitches or thread breakage.
2-B) The tension is too low. The thread take-up spring with too low tension
cannot function well at high speeds or sufcient-
ly take up the thread resulting in a higher possi-
bility of balloon stitches or thread breakage.
2-C) The shape of the thread take-
up spring is inappropriate.
Thread slack may cause catching thread when the
tip of the thread take-up spring is open. If the open
level is too wide, use your nger to close the tip.
2-D) The thread take-up spring ten-
sion is insufcient.
The following capability is insuf-
cient at high speeds.
When #60 or thicker thread is used, the thread
take-up spring used in the A type is too weak
to exert its effect due to insufcient tension of
the spring at the end of the operation. In such
a case, use a standard type thread take-up
spring (or thread tension).
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