SWF E-Series - Page 63

8-5
Error Type Cause
Bad thread (weak,
uneven thickness, poorly
twisted, old)
Right-twisted thread
Excessive thread tension
Tension imbalance
between upper and lower
threads
Excessive tension &
stroke on take-up spring
Inspection & Repair
Change thread
Change to left-twisted thread
Adjust tension
Adjust tension and stroke
Check the thread used.
How to select thread.
•Select soft thread with
ever thickness and
stable tension.
•Choose left-twisted
thread.
Z-direction: left twist
S-direction: right twist
left-twist prevents
unraveling of the upper
thread in the
counterclockwise rotation
of the hook
Reference