Root Causes for Skip Stitch in Garments Sewing Line

 

Identifying Root Causes of Skip Stitch: Ensuring Seam Quality and Reducing Defects in Garments Sewing Lines.

Skip stitch is a common sewing defect in the garments industry where one or more stitches fail to form properly, leaving gaps in the seam. This defect can compromise the strength, appearance, and overall quality of the garment. Skip stitches typically occur due to a combination of machine, operator, thread, fabric, and process-related factors.

1. Machine-Related Causes

• Incorrect needle-to-hook timing.

• Improper needle bar height.

• Worn-out or damaged hook.

• Incorrect thread tension (upper or bobbin).

• Uneven feed dog or presser foot pressure.

• Lack of lubrication or accumulated dirt in machine.

Preventing skip stitches requires proper machine maintenance, correct needle and thread selection, operator training, and adherence to standardized sewing processes. Addressing these root causes ensures improved seam quality, reduces rework, and maintains garment durability.

2. Needle-Related Causes

• Wrong needle size/type for fabric/thread.

• Bent, blunt, or improperly inserted needle.

• Needle overheating during high-speed sewing.

Preventive Actions: 

Use the correct needle type and size for the fabric and thread. Inspect needles regularly and replace worn, bent, or damaged needles promptly. Ensure proper needle installation with the flat side and orientation according to machine specifications. Maintain a needle change schedule based on production volume or fabric type. Train operators to recognize needle damage signs during sewing and avoid prolonged use of faulty needles.

3. Thread-Related Causes

• Poor-quality or uneven thread.

• Incorrect thread thickness.

• Improper threading path through machine guides and tension discs.

• Thread tension too tight or too loose.

Preventive Actions: 

Use high-quality threads suitable for the specific fabric and garment type. Maintain correct upper and lower thread tension according to machine and fabric requirements. Ensure proper threading path and guide alignment before starting production. Match needle size to thread thickness for optimal stitch formation. Store threads in a clean, dry environment to prevent contamination or moisture absorption. Inspect threads for defects, knots, or uneven thickness before use.

4. Fabric-Related Causes

• Stretchy or slippery fabrics (knits, synthetics).

• Thick seam joints or uneven surfaces.

• Improper fabric handling by operator.

• Static or moisture affecting thread control.

Preventive Actions: 

Use the correct needle type and size based on fabric characteristics (e.g., ballpoint for knits, sharp for woven). Ensure even fabric layering and avoid sudden thickness changes at seams. Stabilize stretchy or slippery fabrics with interlinings, tissue paper, or adhesive sprays during sewing. Inspect fabric for defects before production to prevent stitch issues. Train operators on proper handling techniques, including consistent feeding and guiding of delicate fabrics. Adjust machine settings such as presser foot pressure and sewing speed according to fabric type.

5. Operator-Related Causes

• Pulling or pushing fabric incorrectly during sewing.

• Operating machine at excessive speed.

• Failure to adjust machine settings according to fabric type.

Preventive Actions:

Train operators on proper fabric handling and feeding techniques for different fabric types. Ensure consistent sewing speed and maintain smooth, steady motion while sewing. Instruct operators to check machine settings before starting production, including needle type, thread tension, and presser foot pressure. Encourage operators to regularly inspect needles and threads during sewing and replace damaged components immediately. Conduct skill development and refresher training to improve operator efficiency and reduce errors. Implement standard operating procedures (SOPs) for handling delicate or difficult fabrics.

6. Maintenance & Environmental Causes

• Accumulated lint, dust, or debris in machine.

• Delayed preventive maintenance (hook timing, lubrication, part replacement).

• Machine vibration or instability.