How does the Jumbo bag sewing machine sew the lock stitch?

The material of the container bag is flexible, and it needs a professional Jumbo bag sewing machine to process this kind of material. Its design and routing are very consistent with the characteristics of the material and can produce beautiful stitches.

Due to the limitation of the manufacturing process requirements of flexible container bags, the stitches require that the upper thread should bypass the lower thread to form an interwoven, and then the lower thread should be tightened to hide the seam in the seam layer for sewing.

Formation of lock stitch: lead the surface thread through the sewing material to form the surface thread loop. In this link, the needle moves downward to penetrate the sewing material and pass the upper thread through the sewing material. When it moves to the lowest point, it starts to rise up. Due to the resistance between the thread and the needle and the sewing material, the thread outlet is blocked, so that the upper thread accumulates at the bottom of the needle hole and gradually forms a thread loop. The purpose of forming a thread loop is to enable the rotary hook tip to smoothly lead the lower thread through. The upper thread wraps around the bobbin core sleeve to form an interweave with the bobbin thread.

When the top thread loop is formed, the hook point of the rotary hook shell hooks the thread loop. During the motion of the rotary hook, the thread is wrapped around the bobbin core sleeve where the bobbin thread is stored. At this time, the thread take-up rod rises, pulls the thread loop out of the hook point, and the top thread loop around the bobbin thread comes out of the rotary hook. tighten the bottom and top threads and hide the threads in the sewing material. the upper thread loop is combined with the lower thread to form an interwoven thread, which continues to shrink and is folded up in the sewing material. At the same time, the threading hole of the take-up bar rises, and the upper thread is drawn from the threading device to supplement the consumption of the upper thread.

During the sewing process of the Jumbo bag sewing machine, there may be many kinds of bad stitches, which should be adjusted slowly according to the principle and experience of stitch formation, such as floating surface thread, floating bottom thread, loose stitch, shrinkage of the sewing material, etc. The stitch of the Jumbo bag sewing machine is a double-thread interlocking stitch. The correct stitch is that the two intersection points of the upper thread and the lower thread are well interlocked, which are just in the middle of the sewing material. The stitches are not tight or loose, and they are neat and beautiful.