In the production process of woven bags, a common issue encountered during stitching is thread breakage. How can this be addressed?

During the sewing machine operation, the needle thread passes through the fabric, advancing upwards upon reaching the lower limit position due to the friction between the fabric and the thread, which prevents the thread from moving in sync with the needle. Instead, it remains below the fabric, expanding outward towards the needle, forming a loop. As the bobbin needle reaches the needle during its movement, it passes through the thread loop and, in its continuous rotational motion, periodically expands the loop. After wrapping around its own radius, it jumps over the expanded loop, and the subsequent action is for the take-up lever to pull the thread and the feed dog to supply the fabric. To ensure these actions have sufficient time to smoothly interrupt, the bobbin continues to rotate at the original speed, but no longer hooks the thread, merely completing a full rotation in the air.

As the needle reaches the uppermost position, during the subsequent downward thread insertion, the weaving bag sewing machine repeats the motion, creating a regular, intermittent lockstitch pattern on the fabric.