Summary:First of all, from the simplest place, check whether the pressure on the small thread clamp is too high. The small threa...
First of all, from the simplest place, check whether the pressure on the small thread clamp is too high. The small thread clamp controls the length of the thread, if the pressure is too high, the thread is too short, and the thread will come out of the needle hole during the second sewing.
Secondly, when the thread tangent electromagnet is working, pay attention to see if the large thread tensioner bounces off. If it doesn't pop, push the large thread tensioner in a little less.
Third, pay attention to see if the position of the tangent cam is correct, there is a high possibility of a problem in this place.
Fourth, check whether the handwheel is installed correctly and whether the sensor at the handwheel is installed correctly.
Fifth, if it is a brother's computer flat car, or an imitation brother's computer flat car, pay attention to see if the moving knife is installed too far in the front, that is, the tangent is too early.
Sixth, if it is a heavy machine or a machine that imitates heavy machines, pay attention to whether the installation position of the fixed knife is on the far left.
Seventh, pay attention to whether the pressure on the wire stopper is too high.
Eighth, if it is an imitation brother computer car, pay attention to whether the left side of the moving knife is worn. Some of these machines are prone to the tangent precession knife not being reset. If the moving knife is stuck, the needle will collide with the moving knife when the needle is raised for the second time, which will damage the needle and the left side of the moving knife. When there is a scar on the left side of the moving knife, the upper thread will not smoothly enter the gap of the moving knife when the thread is tangent, resulting in the thread being too short. When the needle is started a second time, the end of the thread will come off the eye of the needle.
Ninth, pay attention to whether the wire reel and the wire guide are vertical. If the angle of the wire reel and the wire guide is too different, the resistance of the upper wire will be too large, causing the thread head to be too short when the thread is cut.