SWF MA-6, User Manual, Page: 67 / 76

67
Poor stitch
tension
Needle breaks
① Weak upper thread tension
② Uneven upper thread
tension due to foreign
substances
③ Weak lower thread tension
④ Uneven lower thread
tension
⑤ Thread thickness
⑥ Poor timing of needle and
hook
⑦
Insufficient oil in hook
①
Bent needle
②
Bad quality needle
③
Tip of the needle is worn or
bent
④ Inadequate needle size
⑤ Needle touches the hook
point
⑥
Incorrect installation of
needle
⑦ Needle touches the needle
hole on the needle plate
■ Adjust tension
■ Clean main and sub tension
adjusters in the thread
tension adjusting plate
■ Adjust lower thread tension
■ Clean bobbin case and
check tension on bobbin
spring
■ Change to quality thread
■ Adjust timing
■
Oil the raceway of hook
■
Change needle
■ Space the needle and the
hook point
■
Correct the installation
■ Check if needle plate is
unscrewed
■ Adjust the position of the
needle bar
Inspection & Repair Cause Error Type Reference