SWF MAN-12 - Page 63

63
Thread breaks ⑦ Bad quality thread (weak,
uneven thickness, poorly
twisted, old)
⑧ Right-twisted thread
⑨ Excessive tension on
upper/lower thread
⑩ Tension imbalance between
upper and lower threads
⑪ Excessive tension & stroke
on the take-up spring
■ Change thread
■ Change to left-twisted
thread
■ Adjust tension
■ Adjust tension
■ Adjust tension and stroke
Selecting thread
■ soft, even thickness
tight, left-twisted
■ Z-direction : left
■ S-direction : right
※ left-twist prevents
unraveling in the
counterclockwise
rotation of the hook
Inspection & Repair CauseError Type Reference