Controlling Particulate Migration in Continuous Pad Dyeing Lines
Controlling particulate migration requires stabilizing pad liquor viscosity, balancing wet pick-up, and managing non-contact pre-drying below critical moisture thresholds.
Listing Defects
Selvedge Inconsistency
Variations in color or appearance that occur along the edges of a fabric roll compared to the central portion of the web. These listing defects often stem from uneven pressure in the pad mangle or temperature fluctuations across the width of a drying oven. Such anomalies make it difficult for garment factories to lay out patterns without wasting large sections of material.
Common Cause
Mechanical issues like worn roller bearings or bent axles often create higher pressure at the edges of the cloth. This squeeze forces more dye into the center of the fabric, leaving the edges lighter. In other cases, the edges might dry faster than the middle, causing dye to migrate toward the selvedges and creating a dark border.
Inspection Protocol
Quality inspectors look for these patterns during the final grading process on a backlit table. They measure the shade at the left and right positions along with the center of the web to verify that the color stays within acceptable tolerances. Documentation of these errors helps the mill identify which part of the production line needs calibration.
Finished Quality
Repeatable results are necessary for high volume orders. Severe errors lead to downgrading the entire roll.