Impact of Pectin Removal on Hackling Yield and Line Fineness
Controlled pectin removal enables clean bundle cleavage, elevating metric fibre fineness above Nm 2000 while maintaining long line yield above 60 percent.
Combing Bed
Pin Density
Mechanical pin arrays in hackling machinery penetrate raw flax strands to strip away short fibers and align technical bundles parallel to the sliver axis. The combing bed holds thousands of steel pins arranged in graduated densities across moving field bars to process scutched flax bundles. Coarse pin spacings open tangled bast structures in early passes, whereas finer pin configurations execute final cleaning and bundle division in later zones.
Machine operations cease applying draft forces once the fiber leaves the active pin zone for sliver formation.
Tow Extraction
Separation of short, disoriented fibers from long line flax occurs through repetitive mechanical penetration within the pin field. As raw strands traverse the combing bed, steel pins pull out non-parallel filaments and residual shives into lower collector vacuum ducts. The extraction rate depends on pin penetration depth and bar velocity across the working width.
Inadequate pin penetration leaves residual shives attached to technical fibers, which causes thick places and end breaks in yarn spinning. Excessive pin density or overly aggressive bar speeds break long technical bundles into short fibers, artificially elevating tow yield while diminishing high-value line flax production. Mill engineers adjust the clearance between lower and upper pin sets based on fiber maturity and moisture content to maintain optimal separation efficiency.
Mechanical Tolerance
Precision alignment of pin bars prevents premature needle wear and uneven fiber distribution across the machine width. Standard maintenance schedules for the combing bed require daily inspection of pin straightness and tip geometry to maintain uniform penetration. Damaged or bent pins degrade hackling performance by creating streaks of uncombed flax sliver.