Why is the computer embroidery machine always broken?

Update:24 Nov 2018

Needle a) The smoothness of the needle is not enough, t […]

a) The smoothness of the needle is not enough, the polishing of the needle groove and pinhole is not good, and the needle tip is blunt;
b) the needle is bent or not installed in place;
c) The angle of installation of the needle is incorrect. The wire groove is not in front, too far to the left or right, or the wire groove is on the back;
d) there are attachments (such as glue) in the pinhole;
e) The needle clamp screw is not in the correct position and should be offset to the right by 40 degrees on the front;
2. Line
a) the quality of the wire is poor, the strength is not enough, too hard, too brittle, too many joints on the tower;
b) The rotation is not correct, apply the left-handed line;
c) the tension of the thread is too large;
d) the line is off the line;
e) the line does not match the needle number;
3. Line system
a) Over-hole, over-line wheel, over-line hook, clip line, upper, middle and lower line, take-up pole, take-up spring and other lines at the line are rough or burr;
b) There are burrs on the needle holder and the presser foot;
c) the needle hole is rough or burr;
4. Hook
a) scratches on the hook, or the gap is too large;
b) the surface of the bobbin case is scratched;
c) bobbin case and hook change;
d) there are scratches on the positioning rod;
e) poor lubrication;
5. Parameters (installation location)
a) Needle bar bottom dead center position (172 degrees);
b) hook hook line amount (196 degrees);
c) the height of the needle bar (the center of the pinhole is at the inner plane of the hook at 172 degrees);
d) take-up time (286 degrees);
6. The pattern is too dense or confusing.