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Trouble examples and Corrective actions
2.
Trouble examples and Corrective actions
2-1.
Thread breakage is highly visible.
Cause
Bad thread tension
Quality of thread is bad. Poor thread flow
Direction of needle is bad or needle bents.
Applique glue is stuck on needle.
Contamination, run-out of oil of rotary hook
There are many fine stitches of 0.5 mm or less in
design data.
The fabric is lifted too much against the needle
plate. The fabric touches the needle plate too
much.
Run-out of oil of needle bar
There is a scratch on the thread course.
Bad height of presser foot
If the followings seem to cause the trouble, please ask the distributor for information.
(a) The gap between rotary hook and rotary hook support is narrow. Timing between needle
and rotary hook is too early or too late. Scratch, abrasion of rotary hook.
(b) The gap between needle and hook point is not suitable. Bad adjustment of lower dead
point and/or upper dead point of needle bar.
(c) A play of rotary hook shaft is big in back and forth direction. There is a play on the fringe
of the frame.
(d) Rotation of the main shaft is not smooth. Abrasion/breakage of neighboring parts
of take-up lever drive and/or needle bar drive.
(e) A play of needle bar case (in right and left direction) is big.
Troubleshooting
Adjust tension.
Upper thread 120 to 140 g, Under thread 20 to 30 g
Use good quality thread. Spray silicone.
Adjust to face to the front or to the right a bit. Replace.
Remove adhered glue.
Clean and lubricate the machine.
Remove fine stitch(es).
Stretch the fabric again so that it touches needle plate
lightly.
Lubricate.
Grind it with sandpaper etc. Replace.
Perform adjustment so that height fits to fabric/
material.
Chapter 9
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