Understanding High-Speed Sewing Machines

Currently, high-speed sewing machine is becoming increasingly popular, and the correct choice of sewing thread plays a significant role in ensuring the quality of stitched garments.

Sewing thread is composed of two or more single yarns that are twisted together. After twisting, the fibers or strands within the thread exhibit a slanting direction, which we refer to as "twist direction." The twist direction is divided into "S twist" and "Z twist," also known as "left twist" and "right twist."

For high-speed lockstitch machines, the face thread should be selected with an "S twist." Otherwise, when the face thread passes through the needle hole from left to right, it will experience strong "untwisting." According to calculations, a fixed point on the sewing face thread needs to pass through the needle hole approximately 70 times before it can be securely joined with the bobbin thread on the fabric. This repeated process causes severe "untwisting" in the "Z twist" thread. Excessive "untwisting" in the sewing thread can hinder the formation of loop stitches in the bobbin area, leading to skipped stitches and frequent thread breaks due to reduced thread strength.

"S twist" thread, when subjected to repeated friction against the needle hole, is relatively resistant to severe "untwisting" due to its twist direction, allowing the thread to maintain higher physical strength and performance. This reduces the occurrence of skipped stitches and thread breakage.

For double-needle machines, the left needle presents a different scenario. Since its threading direction is opposite to that of regular lockstitch machines, it actually requires the use of "Z twist" thread to avoid severe "untwisting." Otherwise, it often results in thread breakage with long tufts. This negatively impacts production efficiency and stitch quality.

If "Z twist" thread is not available, the left rotary hook of the double-needle machine should be fine-tuned to position the hook tip as close to the left machine needle as possible. Correspondingly, reduce the pressure of the tension spring and the movement of the thread take-up lever to mitigate the adverse effects of the thread twist direction. Additionally, it is advisable to use a 3-ply twisted sewing thread to enhance resistance to "untwisting."

As for the twist direction of the sewing machine bobbin thread, there are no restrictions, and it can be used for both single-needle and double-needle sewing machines.

If you need to purchase a High-Speed Sewing Machines, you can choose DAPSEW. The brand we cooperate with is the Juki Sewing Machine.

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Email: evan@dapsew.com

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