SunStar KM-750 User Manual page 35

No Symptom
The gap between the
movable knife and the
hook
Check the tension of
fixed knife
5
Trimming errors
Direction of the needle
Blade side of movable
and fixed knives
Trimming cam timing
Thread release stroke
Trimming timing
Opening of the thread
tension adjusting plate
Too short thread
Tension of auxiliary
length after
thread tension
6
trimming
adjustment assembly
Thread take up stroke
Thread release
adjustment volume on
the control box
Checkpoints
The height and distance between the
movable knife and the hook do not match
Tension and contact of movable and
fixed knives are bad
Needle is not inserted correctly
Scratch and abrasion of movable and
fixed knives
The timing of trimming cam is wrong
Thread release stroke is too small
Wrong trimming timing
The opening on the thread tension
control plate is too small
Too strong tension on the auxiliary thread
tension control assembly
Thread take up stroke is too large
Volume is adjusted to too low
Root cause
Readjust the movable knife setting
position
Correct the tension adjustment and
surface contact of movable and fixed
knives.
Insert the needle correctly
Replace movable knife or fixed knife.
Adjust the timing of trimming cam
Readjust the thread release stroke
Adjust the trimming timing
Adjust the thread release stroke
Adjust the tension of the auxiliary thread
tension control assembly
Adjust the thread take up stroke
Increase the volume adjustment.
Corrective action
35