I. Common Dyeing Defects
1. Seam Marks: Darker areas appear at both ends of the silk fabric.
Causes: The seam is too wide or thick; excessive tension; the guide silk is too short; or there is a significant difference in color/texture between the guide silk and the fabric being dyed.
Prevention: Make a few cuts at the seam to reduce water accumulation; adjust tension; ensure the guide silk length and texture/color match.
2. Uneven Colors: The silk fabric has uneven color distribution at both ends.
Causes: The guide silk is not clean; the dye is added in the wrong order; no cover is used; improper temperature control; dye is squeezed out of the guide silk.
Prevention: Keep the guide silk clean; add dyes according to their properties; use a cover during dyeing; strictly control the temperature; ensure the guide silk and dye fabric are of uniform texture.
3. Uneven Colors at the Edges: The edge color is different from the center.
Causes: Uneven fabric width upon loading, lack of a cover, improper dye selection, excessive curvature of the fabric stretcher, temperature or pH difference between the edge and center.
Prevention: Ensure even fabric width upon loading, select dyes with similar dyeing temperatures, avoid excessive curvature of the fabric stretcher, and strengthen pretreatment to maintain consistent pH.
4. Wrinkles: Warp wrinkles.
Causes: Uneven seam ends, uneven winding, uneven fabric width, excessive water jet impact, excessive tension, non-level fabric stretcher, too many yarn knots on the rollers.
Prevention: Even seam ends, even fabric width, avoid excessive steam during boiling dyeing, moderate tension, maintain a level fabric stretcher, and clean the dyeing cylinder.
5. Weft Skew: Skewed weft yarns.
Causes: Inconsistent hand pressure when loading the fabric into the dyeing vat, water jet impact during boiling dyeing.
Prevention: Ensure even hand movements when feeding the fabric into the dyeing vat; avoid excessive water pressure during dyeing.
6. Loose board marks: Resembling the rings of a tree after sawing.
Causes: Excessive tension or temperature during fabric winding.
Prevention: Avoid excessive tension during fabric winding; use cold water for winding.
7. Color bands: Horizontal bands of varying shades appear on the fabric surface.
Causes: Mechanical malfunction causing shutdown.
Prevention: Carefully check the operation of all machine parts before restarting.
8. Color difference: Color differences between rolls.
Causes: Inconsistent process control.
Prevention: Strictly control process conditions to ensure consistency.
II. Common Mechanical Faults
1. Transmission system faults: Loose or broken belts/chains, worn or abnormally noisy gears, damaged bearings causing vibration or noise.
2. Electrical Control System Faults: Motor overload, inverter failure, sensor malfunction, abnormal control panel display.
3. Tension System Faults: Abnormal tension frame curvature, inaccurate tension sensor, malfunctioning automatic turning device.
4. Heating System Faults: Uneven steam heating, temperature control malfunction, aging seals causing steam leakage.
5. Safety Device Faults: Emergency stop button malfunction, loose safety cover, missing protective devices.
III. Fault Diagnosis and Maintenance Key Points
1. Regular Inspection: Establish a daily inspection and regular maintenance system, focusing on key systems such as transmission, tension, and electrical systems.
2. Record and Analysis: Record fault phenomena, occurrence time, and handling process in detail, analyze patterns to prevent recurrence.
3. Prevention First: Reduce sudden faults through standardized operation, timely maintenance, and spare parts management.
