I. Uneven Dyeing (Color Spots)
Causes: Inaccurate liquor ratio (too high or too low), uneven dye liquor circulation, excessively rapid heating rate, inadequate fabric pretreatment (e.g., oil stains, impurities), or poor dye dispersion.
Solutions: Check the circulation pump and pipeline for blockages; optimize the heating curve, using staged heating (e.g., slow heating above 80℃); ensure sufficient dyeing, using a sieve to filter dye particles.
II. Wrinkles and Claw Marks
Causes: Excessively rapid cooling leading to uneven fabric shrinkage, or inconsistent fabric tension during dyeing.
Solutions: Control the cooling rate; it is recommended that the temperature change per cycle not exceed 1–1.5℃; for fabrics already wrinkled, reheat to a few degrees above the original dyeing temperature and then slowly cool to repair.
III. Excessive Foam
Causes: High-speed circulation generates turbulence, or the use of highly foaming dyes or auxiliaries, or residual treatment agents on the fibers causing foam.
Solutions:
IV. Nozzle Clog and Poor Dye liquor circulation
Causes: Accumulation of impurities in the dye liquor, failure to clean the filter screen in time, and accumulation of fiber lint.
Solutions: Clean the filter screen regularly (once per shift for medium-length fibers, once a day for filaments); disassemble and clean the nozzles and pipes when the machine is stopped to prevent hardening of residues.
V. Abnormal temperature control
Causes: Heat exchanger malfunction, temperature control sensor failure, or incorrect PLC system parameters.
Solutions: Regularly calibrate the temperature instrument and check whether the heating/cooling valves are responding normally; high-end models can use online feedback control for dynamic adjustment.
VI. Post-dyeing staining or poor whiteness (especially for whitening varieties)
Causes: The dye bath was not thoroughly cleaned before dyeing a lighter color, resulting in residual dye contamination. Solution: Before changing from dark to light, a high-temperature alkaline wash (130℃, caustic soda + detergent) is necessary. If the original tank was red, it should be gradually transitioned to blue tones before lightening to avoid direct whitening.
