Condition
6. Noisy
1. Backlash between
operation
2. Lower shaft gear is loose.
3. Inappropriate belt tension.
4. Not enough oil.
5. Upper shaft is loose.
7. Deformed
1. Inappropriate feed
pattern
2. Inappropriate zigzag
3. Upper thread tension
Improper
8.
1. Buttonhole stitch
buttonhole
results
2. Changing to bar tack
Cause
shuttle hook gear and
lower shaft gear is too
great.
balance.
synchronization.
is too strong.
balance is not correct.
is too early or will not
work.
How to fix
See mechanical
adjustment "Backlash
between Hook Gear and
Lower Shaft Gear".
Eliminate the looseness.
See mechanical adjustment
"Motor Belt Tension."
Oil all moving parts.
Eliminate the looseness.
See mechanical adjustment
"Stretch Stitch Balance."
See mechanical
adjustment "Needle Swing."
Adjust needle thread
tension correctly.
See mechanical adjustment
"Buttonhole Feed Blance".
See mechanical adjustment
"Buttonhole Length".
3
Reference
p.21
p.27
p.16
p.13
p.24
p.26