JUKI LK-1900A Series Engineer's Manual page 39

Adjustment Procedures
After thread cutting, the wiper spring
with the aid of the wiper
set screw so that the intensity of the spring force becomes 30g (some-
what stronger than that of the bobbin thread that is protruded from the
bobbin case).
1. Remove the set screw
wiper .
2. Adjust the wiper spring
means of the screw
(Caution) 1. If the holding force is too strong, the thread may be
protruded above the button.
2. If the holding force is insufficient, needle thread cast-
off may occur.
3. If the wiper spring
needle thread cannot be held correctly and this can
be a cause of needle breakage.
Adjustment Procedures
1. Loosen the two set screws
motor and the two set screws
plate .
2. Pressing it in the direction of the arrow
screws in the first place. Then, tighten the two remaining set screws
and another two set screws
3. Loosen the four set screws
the direction of the arrow
is used to hold the needle thread
. Adjust the wiper spring
and take out the wiper spring
and mount it on the wiper
.
position is inadequate, the
and four set screws
of the X feed motor mounting
, tighten the two upper set
C
, X feed motor mounting plate
of the X feed motor
, tighten the set screw
B
and fix it with the
from the
again by
of the Y feed
o If the pressing force is insufficient,
.
. Pressing it in
.
– 35 –
Results of Improper Adjustment
Results of Improper Adjustment
feed gear backlash becomes too
m u c h a n d n e e d l e l o c a t i o n
accuracy may be decreased. This
can also be a cause of feed error,
needle breakage, etc.