Double-needle sewing machine repair

 

The double-needle sewing machine, also known as a twin-needle flatbed machine, is a commonly used sewing machine that produces a double parallel effect with two synchronized needles, three synchronized needles, or a turning corner stitch. 

The double needle has high efficiency, and the double parallel lines are neat and beautiful. It is commonly available in both manual and computerized models and is suitable for thin to thick fabrics.

Although the double-needle sewing machine has high working efficiency, it is prone to phase dislocation after some use, which is not easy to adjust. At this time, repair personnel is prone to enter the repair misunderstanding.

Misunderstanding 1: General machine repair will adjust the needle bar to match the feed dog hole and ensure the needle drop point is in the middle of the feed dog hole, especially when there is a long hole. Also, the timing of the needle and the shuttle needs to be coordinated. The lower dead point of the machine needle is adjusted according to the sewing fabric. When the machine needle rises 2.2mm from the lower dead point, or when the lower end surface of the downstroke line and the needle post sleeve is level, move the shuttle shaft holder left and right to make the distance between the machine needle and the shuttle tip 0-0.05mm, the distance between the machine needle and the needle stopper 0-0.07mm, and the centerline of the machine needle and the shuttle tip coincide. Adjust the hooking time faster or slower based on the actual situation. Rotate the handwheel to place the thread hook in the final position. Rotate the inner shuttle in the opposite direction of the shuttle rotation direction so that the shuttle stopper contacts the needle plate groove. Loosen the fixing screw of the thread hook, and adjust the gap between the triangular stopper on the inner shuttle and the thread hook to 0.2-0.3mm. If the gap is too large, the thread may become loose or break, and if the gap is too small, the thread hook may be damaged. Don't forget to adjust the gap between the top of the needle plate groove and the top of the shuttle stopper to 0.8-1.0mm. Change the sleeve pad on the shuttle shaft to change the height of the shuttle.

Misunderstanding 2: General machine repair will raise the needle plate to adjust its gap. Coordinate the timing between the upper shaft and the lower shaft. Remove the synchronized toothed belt from the toothed wheel, and rotate the handwheel to align the markings on the handwheel with the markings on the machine head. Rotate the lower shaft until a small hole on the machine base aligns with the first screw on the lower shaft toothed wheel. Ensure that the position of the upper shaft and the lower shaft remains unchanged and then install the synchronized toothed belt.

When double-needle sewing machine repairing, pay attention to the above two points and avoid encountering the same problem to reduce the troubles in the repair process.