NLI DS-9 Series, Руководство пользователя, Страница: 17 / 52

Problem Cause Solution Ref.
Needle (looper)
thread breaks
1. Damaged looper
2. Too much thread tension
3. Too little thread tension
4. Thread snarled or hung up along path between thread stand
and needle/looper
5. Incorrect threading. Thread not between tension discs
6. incorrect needle setting
7. Bent or damaged needle
8. Double sewing
9. Decreased stitch length because of worn feed dog teeth
Replace
Decrease
Increase
Correct
Thread correctly
Set correctly
Replace
Move up thread controller
Replace feed dog
5-3
5-1
5-1
3
3
5-3-b
5-3-b
5-1
5-4-b
No chain formed
between bags
1. Incorrect threading
2. Too much looper thread tension
3. Too little needle thread tension
4. Thread controller too low
5. Needle and looper not timed each other
6. Not enough presser foot pressure
7. Thread is cut by feed dog teeth
8. Thread is feedback because feed dog is set too high
Thread correctly
Decrease
Increase
Move it up
Adjust timing
Increase
File the row of feed dog teeth that
comes in touch with thread
Adjust height of feed dog
3
5-1
5-1
5-1
5-3-c
5-2
5-4
5-4-b
Skipping stitchs
1. Wrong setting of needle
2. Bent or damaged needle
3. Thread controller too low
4. Worn looper point
5. Needle too high
6. Thread sticking to needle due to heat
7. Needle guard pushing needle
8. Looper thread too loose to form a good triangle (reverse skip)
9. Needle and looper wide apart (scoop skip)
Set correctly
Replace
Move it up
Replace looper
Lower needle bar
Dampen needle thread with oil
Adjust needle guard
Increase looper thread tension
Adjust distance needle to looper
5-3-b
5-3-b
5-1
5-3-c
5-3-b
*
5-4-d
5-1
5-3-c
Needle or looper
breaks
1. Bent needle
2. Looper point hitting needle. Needle point hitting looper
3. Needle guard pushing needle or they are wide apart
Replace
Adjust timing of needle and looper
Adjust needle guard
5-3-b
5-3-c
5-4-d
Stitch length not
uniform, Curved
seam
1. Not enough presser foot pressure
2. Worn feed dog teeth
3. Bent needle
Increase
Replace feed dog
Replace
5-2
5-4-b
5-3-b
Thread bites into
crepe tape
1. Two much needle thread tension
Decrease
5-1
Crepe tape creases
1. Feed dog, rear, is higher than feed dog front a little
Adjust height
5-4-b
6. Troubleshooting
＊ Plastic contents existent in bag material is melt by the heated needle and may stick to needle, etc., causing skipping
stitches. When closing woven cloth bags, kraft paper bags inclusive of polyethylene coated layer, polyethylene and PVC
bags, etc., dampen needle thread with oil to prevent sticking of plastic contents. Use silicone oil processed thread for
packing rice and other food products.
13