Analysis of Common Defects and Solutions in Warp Knitted Fabrics

Warp knitting machines often encounter mechanical malfunctions and fabric defects during the knitting process, and the causes are diverse and complex.

For ease of troubleshooting, based on practical experience, the issues can be broadly categorized as follows:

1. Poor quality of mechanical parts, inadequate installation and coordination of components, and subpar maintenance lead to severe wear of parts during prolonged operation.

2. Issues arising from raw material quality, such as improper selection of raw material and yarn fineness, resulting in defective yarn during spinning. Problems like thick/thin places, impurities, neps, weak twist, or insufficient washing and softener usage during dyeing and finishing can also contribute.

3. Inadequate preparation processes, including excessive spacing in clearing the yarn, presence of thick yarn or yarn ends not properly cleared, and improper lubricant usage.

4. Lack of proficiency in the operation of knotting and carriages by the warper and guide bar operator.

5. Poor quality of knitting machine components (knitting needles, yarn carriers, etc.) and improper adjustments.

6. Unreasonable process planning, such as mismatching yarn fineness with machine gauge.

 Analysis of Common Fabric Defects and Causes of Mechanical Failures in Warp Knitting:

1. Oil Stain:

Oil stains occur when continuous or intermittent oil stains appear on the fabric surface during the knitting process, affecting the dyeing outcome. It results from issues like insufficient oil supply or improper machine operation. Regular oiling, cleaning, and proper machine operation can prevent oil stains.

2. Missed Stitches:

Missed stitches happen when knitting needles fail to catch or retain newly fed yarn, resulting in a loop dropping out after being formed. Causes include insufficient triangle tension and inadequate lubrication. Adjusting the triangle tension and ensuring proper oiling can address missed stitches.

3. Holes:

Holes in the fabric occur due to insufficient yarn strength, variations in yarn thickness, impurities, and mechanical issues. Adequate yarn strength, proper yarn preparation, and regular machine maintenance can prevent holes.

4. Flowering Needle:

Flowering needles result in uneven loop sizes within a vertical column of stitches. Causes include insufficient triangle tension and oiling issues. Adjusting the triangle tension and ensuring proper lubrication can resolve flowering needle defects.

These solutions aim to address the identified defects and improve the overall quality of warp-knitted fabrics.