64
Poor Thread
Tightening
Needle Break
①
Weak tension of the upper
thread
②
Uneven tension of the
upper thread due to foreign
materials
③
Weak tension of the lower
thread
④
Uneven tension of the
lower thread
⑤
Thread thickness
⑥
Inappropriate needle and
hook timing
⑦
Insufficient oil supply to
the hook
①
Broken needle
②
Bad needle
③
Abrasive or deformed tip of
the needle
④
Inappropriate needle for
embroidery fabric or thread
used
⑤
Contact between the needle
and the hook point
⑥
Wrong placement of the
needle
⑦
Contact of the needle near
the needle hole on the
needle plate
■
Adjust the tension of the
upper thread
■
Clean the main tension
adjusting device and the
auxiliary thread tension
adjusting device on the
thread tension adjusting plate
■
Adjust the tension of the
lower thread
■
Clean the bobbin case and
check the bobbin pressure
spring
■
Replace the thread with the
good quality one
■
Readjust the needle and the
hook timing
■
Correct the hook point with
the whetstone or replace the
hook
■
Replace the needle
■
Adjust the distance between
the needle and the hook
point
■
Properly install the needle
■
Check whether the
tightening screw for the
needle plate is loosened
■
Adjust the needle bar
location
Corrective Action and Check Point
Cause of Trouble
Type
Remarks