Skipped stitches and thread breakage are common malfunctions in lockstitch sewing machines that directly affect sewing efficiency. Skipped stitches are often caused by incorrect needle bar height or worn needles. The needle bar position should be adjusted to the correct height according to specifications, and specialized needles should be replaced regularly.
Thread breakage is usually due to excessive thread tension or frequent needle breakage. It is important to check the thread tension adjustment mechanism to ensure proper tension, and inspect the needle for bending or wear, replacing it as needed. In addition, an unevenly wound bobbin may cause the lower thread to loosen and break; thus, the bobbin winding should be optimized for uniformity.
By systematically troubleshooting these key factors, the machine’s stable operation can be quickly restored.