Quantifying Wet Spinning Limits for Low Cohesion Bast Fiber Slivers
Low cohesion flax slivers collapse under high draft ratios, requiring reduced trough temperatures, higher roving twist, and tight ratch settings to hold count.
Combing Noil
Fibre Classification
Short-staple material rejected during the hackling and combing phases of flax preparation represents a valuable secondary raw material for coarse yarn manufacture. This residual fraction, known as combing noil, consists of fibres below the critical length required for high-line wet spinning. It remains after the long-line combed sliver is drawn off, collecting on the combs of the rectilinear or circular combing machines.
In many flax mills, this material is gathered and pressed into bales for separate processing or sale.
Industrial Extraction
Mechanical separation on the combing head isolates these short fibres from the long-line flax sliver through a series of timed needle penetrations. The comb needles retain the aligned long fibres while brushing out the combing noil, which contains short tangled fibres and remaining fragments of shive. This action is carefully calibrated to ensure that the yield of high-value line flax is maximized without allowing short fibres to remain and weaken the primary yarn.
Yarn strength decreases when the extraction rate is too low. The percentage of extracted combing noil determines both hackling efficiency and raw flax quality, balancing sliver yield against the target count of the spin plan.
Spinability Limit
Secondary spinning operations utilize this material to produce coarse yarns for heavy fabrics or industrial cords. Because the average length of combing noil is low, the spinning limits are restricted, and rotor spinning or dry ring spinning with high twist is required to bind the short fibres. The resulting yarns have higher hairiness and lower tensile strength than those made from long-line sliver.