I. Equipment Operational Abnormalities
These problems often stem from mechanical wear, control system malfunctions, or inadequate maintenance:
1. Slow Heating/Cooling: Scaling in the heat exchanger or unresponsive steam valves cause delayed temperature control.
2. Uneven Dye Bath Circulation: Clogged nozzles, worn pumps, or accumulated residue in pipes result in uneven dye bath concentration distribution.
3. Tension Loss: Inaccurate sensors or inverter malfunctions cause uneven fabric tension during operation, easily leading to wrinkles or weft skew.
4. Sealing Leaks: Under high temperature and pressure, aging and cracking of the cylinder head seal pose a safety risk.
5. Abnormal Noise or Vibration: Caused by worn fabric roll bearings, poor gear meshing, or deformed tensioning frame.
II. Dyeing Quality Defects
These problems directly manifest on the fabric surface and are the result of poor coordination between the process and equipment:
1. Uneven Color (Inconsistent Color Depth)
Causes: Excessive heating, premature addition of dyeing accelerator, failure to cool down after adding dye during the process.
Prevention: Control the heating rate after 80℃; add dyes and auxiliaries in batches and ensure they are fully dissolved.
2. Horizontal Color Difference (Horizontal Color Difference)
Causes: Mechanical malfunction causing shutdown, resulting in repeated dyeing of the stopped areas of the fabric.
Prevention: Check the operating status of all components before restarting to avoid unplanned shutdowns.
3. Seam Marks (Darker Seams at Both Ends)
Causes: Seam marks are too wide or thick; inconsistencies between the guide fabric and the dyed material; or excessive tension.
Prevention: Use scissors to prevent water accumulation at the seam marks; adjust tension to a moderate level.
4. Color Difference at Both Ends of the Fabric (Difference in Color Between the Two Ends of the Fabric)
Causes: Unclean guide fabric; temperature fluctuations; or dye seepage into the seam.
Prevention and Control: Keep the fabric guide clean and cover it for insulation during dyeing.
5. Difference in color between edge and center (color difference)
Causes: Fabric edge cooling too quickly, uneven pH value, or excessive curvature of the fabric stretcher.
Prevention and Control: Turn on the heating element of the cover and strengthen the pretreatment to ensure uniform pH.
6. Wrinkles (straight wrinkles in the warp direction)
Causes: Uneven seam allowance, excessive tension, or strong water jet impact.
Prevention and Control: Ensure the seam allowance is flat and adjust the steam pressure to a moderate level.
7. Loose board marks (annual ring pattern)
Causes: Excessive tension and temperature during roll-up.
Prevention and Control: Use cold water for roll-up to reduce initial tension.
8. Weft skew (skewed weft direction)
Causes: Uneven hand movements when entering the dyeing vat or excessive water jet impact.
Prevention and Control: Standardize operating techniques and control the intensity of the boiling dyeing steam.
9. Small color spots on the silk surface (irregular dark spots)
Causes: Incomplete dissolution of dye, inadequate cleaning, or precipitation due to anion-cation reaction.
Prevention: Use filtered dyes and keep equipment clean.
