Duerkopp Adler 579 Service Instructions Manual page 83

Loose Stitches
The buttonhole is not cut
open cleanly
Needle breakage
Thread-guiding parts, such as
e.g. thread conductor, thread
guides or thread take-up disk
have sharp edges
Check if the needle plate, the
looper or the spreader have
been damaged by the needle
The thread tensions are not
appropriate to the material, the
material weight or the threads
used
Incorrect threading of the
needle or looper thread
The set cutting pressure is too
low
The knife edge is dull or broken
out
The knife is working on a
non-corresponding cutting
block.
If buttonholes are cut open
before or after sewing or if
buttonholes are sewn with or
without eyes, the corresponding
cutting block is always to be
used. Cutting blocks with two
knife impressions lead to an
unclean cut
The needle thickness is
inappropriate for the material or
the thread
The needle strikes on the cloth
clamps
The E-group is inappropriate to
the set subclass
Faulty transport of the cloth
support plate or sewing
mechanism
With a change in the seam
width, the cloth clamps were not
set or set too close together
Check the thread path to see if
thread-guiding parts have sharp
edges
Have the parts dressed by service
personnel.
Check the thread tensions
(see Operating Instructions
"Thread Tensions")
Check the threading of the needle
and looper threads (See Operating
Instructions "Threading the Needle
Thread"/ "Threading the Looper
Thread"
Increase the cutting pressure (see
Chapter "Cutting Pressure")
Insert a new knife (See Chapter
"Eye Knife")
Dress the cutting block or insert a
new cutting block.
(see Chapter "Dressing the Cutting
Block ")
Change the needle thickness
Check the subclass in the control
panel
See under "Faulty Transport of the
Cloth Support Plate"
or
"Faulty Rotation of the Sewing
Mechanism"
Set the upper and lower cloth
clamps as far apart as required
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