Optimizing Relay Nozzle Dynamics for High Hairiness Bast Fiber Shedding in Air Jet Looms
Optimizing relay nozzle pressure vectors, timing overlap, and reed profile clearance eliminates hairiness-induced stops in high-speed bast air-jet weaving.
Fiber Hairiness Index
Spinning Measurement
Laser scanning technology quantifies the protrusion of individual flax stalks from the central body of a yarn during the final stages of carding or spinning. The fiber hairiness index provides a numerical value based on the total length of these detached filaments per centimeter of material. Mills utilize this data to predict downstream performance during high speed weaving or knitting operations.
High values indicate poor fiber control and a high risk of surface pilling in the finished linen cloth.
Procurement Standard
Quality control laboratories record these values on the technical specification sheet that accompanies a mill output lot for buyer approval. Commercial contracts for linen yarn often specify an upper limit for this metric to ensure the stability of the final textile surface. When the count exceeds the agreed limit, the yarn batch undergoes secondary gassing or singeing to remove protruding ends.
Such processes reduce the hairiness value but often decrease the overall diameter of the finished product. These adjustments introduce additional cost and potential damage to the flax material, forcing a balance between surface finish and structural integrity.
Process Influence
Mechanical friction and air turbulence during the ring spinning stage govern the extent of surface protrusion. Settings on the drafting rollers change the alignment of short fibers within the main strand and determine the frequency of loose ends. Higher spindle speeds generate more centrifugal force and frequently lift fibers away from the yarn core.
Regular calibration of the measuring laser ensures the consistency of these values across different production lines and varying flax qualities. Careful observation of this index prevents the production of suboptimal fabric that fails to meet standard export requirements.