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 PointCause of TroubleType Remarks
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