Application Measurement
Quantitative assessment of the amount of finish or lubricant applied to a fibre surface is expressed as a percentage of the dry yarn weight. This oil pick-up value indicates the efficiency of the spin finish application during the extrusion or texturing process. Correct levels are necessary for ensuring the yarn performs well in downstream operations like knitting or loom processing.
Testing Procedure
Laboratory technicians determine this value by extracting the oils from a known weight of yarn using a suitable solvent. The solvent is then evaporated, and the residual oil is weighed to calculate the percentage. Rapid methods like Nuclear Magnetic Resonance (NMR) spectroscopy provide an alternative that does not require hazardous chemicals.
Regular testing ensures that the application rollers or spray systems are functioning correctly across all production lines.
Process Boundary
Insufficient lubrication leads to high friction and static electricity, while excessive oil causes slippage and buildup on machine parts. Most synthetic yarns require an oil pick-up between 0.5 and 1.5 percent depending on the final use. Deviations from this range result in poor package formation or uneven dyeing results.
Operational Control
Maintaining a steady pick-up rate requires precise control of the finish concentration and the speed of the application rollers. Changes in the ambient temperature or humidity can affect the viscosity of the oil, necessitating adjustments to the equipment settings. Detailed logs of these measurements provide a record for quality assurance and help in troubleshooting performance issues reported by the knitting mill.
The consistency of the lubricant layer determines the ultimate efficiency of high-speed textile manufacturing.
