JUKI DDL-9000 Engineer's Manual page 14

(Reference) 1. Marker dot on the handwheel shows the standard value of cam timing. The timing can be more advanced
by 2˚ or more delayed by 5˚ than that in case of cotton thread or synthetic thread. At this time, however,
confirm that moving knife securely separates two pieces of needle thread at the bottom face of throat
plate. If the cam timing is excessively advanced or delayed, the needle thread remaining at the top of
needle will be shorter and may slip from the needle immediately after thread trimming. In addition,
roller may not enter the groove of thread trimmer cam. So, be careful.
2. Basically, the thread trimmer cam timing is common to cotton thread and synthetic thread. For the thin
synthetic thread, however, if the following troubles occur :
① One or several stitches skip at the start of sewing.
② Thread slips from needle at the start of sewing.
Perform the following adjustments for synthetic thread (special) (In case of thin threads)
③ Align marker dot on the machine arm (Fig 13 (3)) with green marker dot on the handwheel (Fig.
13 (1)) and adjust thread tension No. 1 to lengthen the thread remaining on the needle after
thread trimming within the range that nothing interferes with the finish of sewing.
④ Make one stitch of soft start at the start of sewing.
[Caution] Adjustment ① is not applied to thick threads.
When thread trimmer cam timing is delayed (in the direction of green), phenomena such as
dispersion of adjustment, non-trimming of thread without completing thread trimming depending
on the kinds of threads may occur.
In this case, slightly delay the needle upper stop position.
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