Standard positioning of overlock sewing machine needle and upper and lower looper
(1) The height positioning of the needle.
When the needle rises to the highest point, the needle tip will reach the plane of the needle plate (2 threads and 3 threads are 9-10 mm, 4-thread left needle is 9-10 mm, right needle is 8-9 mm, 5-thread chain thread The needle is 7.5-5.8 mm, and the hemming needle is 9-10 mm).
(2) The positioning of the needle, the lower looper and the chain hook.
When the lower looper and chain hook swing to the leftmost position, the distance between the needle tip and the needle at the lowest time (3 thread is 3.5～4 mm, 4 thread is 2.8～3.1 mm, left needle, 5 thread is 3.5 ～4mm), the inclination angle of the looper is 3°～6°, and the gap is 0.05mm; the distance from the tip of the 5-thread chain crochet needle to the needle is 2.5～3mm, and the crochet angle is 5°～7° .
(3) The positioning of the needle, the upper looper and the upper fork needle.
When the upper looper and the upper looper needle slide bar reach the top dead center (the distance from the fork needle to the needle on the 2nd thread is 4 to 4.5 mm, the needle tip of the 3-thread machine goes down to the upper looper needle when it comes into contact with the upper looper needle The distance to the needle is 4 to 4.5 mm, the looper needle hole on the 4th line is in the middle of the two needles, the 5th thread is the same as the 3rd thread), and the gap between the upper looper and the lower looper is 0.10 mm.
