–
79
–
Trouble Case (1) Case (2) Check and Corrective measures
8. Faulty chain-o thread 8-1) Position of the throat
plate
1-A) The throat plate has been improperly
positioned longitudinally, and chain-o
thread gets in between the main feed
dog and throat plate, causing defective
chain-o thread.
Correctly position the throat plate.
* Provided that no chain-o trouble
occurred when sewing operation
was done with materials set on
the machine.
8-2) Feed dog 2-A) The auxiliary feed dog is too high, and
interferes with chain-o thread.
The auxiliary feed dog is too low.
Refer to the pertinent Standard Adjustment.
2-B) The auxiliary feed dog has scratch. Repair or replace the auxiliary feed dog.
8-3) Adjustment of looper 3-A) Adjustment of loopers for producing
chain-o thread without materials re-
quires higher accuracy.
Refer to the pertinent Standard Adjustment.
8-4) Thread tension 4-A) The thread tension is too low. Slightly increase the tension.
4-B) The needle thread tension is too high,
causing damaged balance with other
thread tension.
Check whether the needle thread take-up guide
or needle thread guide is positioned too high
with consequent excessive needle hread ten-
sion. And if so, correct it.
9. Overlocking needle thread is
loose
9-1) Position of the needle
thread take-up guide
and needle thread
guide
1-A) They are positioned too high, and the
threadtake-up draws out excessive nee-
dle thread.
Refer to the pertinent Standard Adjustment.
9-2) Thread tension 2-A) The thread tension balance has been
disturbed.
Refer to the Standard Adjustment for the looper
thread take-up components, and increase the
tension if necessary.
9-3) Needle 3-A) The needle is too thin for the thread
used.
Replace it with a proper one.
To Next Page
Loading...
