Mechanical Volumetric Dosing Calibration for Textile Pad Dyeing Systems
Mechanical volumetric dosing calibration requires gravimetric cross-verification and pressure-balanced manifolds to prevent shade tailing in pad dyeing.
Tailing Shade Variation
Colour Drift
Longitudinal shifts in chromatic appearance between the start and the end of a single fabric run indicate liquor instability. Occurrences of tailing shade variation usually arise from the preferential absorption of specific dye components by the textile as it passes through the padder.
Chemical Mechanism
If the liquor replenishment rate does not match the actual consumption of each individual dye, the bath concentration changes over time. This depletion leads to tailing shade variation where the end of the roll looks lighter or different in hue from the beginning. Correcting this involves adjusting the feed rates or the initial concentration in the preparation tank to compensate for differential strike rates.
Improving the circulation within the padder trough helps in keeping the mixture uniform and reduces the chance of depletion zones.
Production Check
Lab technicians take samples from both ends of the finished batch to verify conformity within specific Delta E limits. When tailing shade variation exceeds the tolerance, the batch must be re-processed or downgraded for secondary uses.
Operational Limit
Factors like temperature gradients or speed fluctuations also contribute to these visual shifts. Consistent tracking of tailing shade variation identifies which dye combinations are prone to instability on particular fibre types.