Modeling Elementary Cross Sectional Variances to Predict Wet Spinning Breakage
Modeling elementary fiber cross-sectional variance predicts wet spinning end breaks by identifying localized cell wall stress concentrations under drafting tension.
Bundle Cohesive Force
Drafting Resistance
Measurement of the resistance to sliding in a parallel assembly of untwisted bast fibers provides an index of the fiber bundle interaction during the drawing process. The bundle cohesive force determines how individual fiber strands glide past one another in the drafting zone. It governs the uniformity of the sliver prior to twisting.
Surface Adhesion
Chemical composition of standard pectin on the outer cell walls of flax governs the frictional behavior of the fibers during processing. Residual hemicellulose acts as a natural binding agent that increases the bundle cohesive force during dry drawing operations. In wet spinning, warm water baths soften these pectin compounds, which lowers the cohesion and allows finer drafting.
Mill laboratories measure this force by recording the peak tension required to draw a sliver through a set of stationary pins. Controlling this property requires regular assessment of the retting process, because under-retting leaves excessive adhesive compounds on the fibers, which increases the required drawing tension and leads to uneven yarn.
Process Optimization
Adjustments to the nip distance and pressure of the drafting rollers must align with the measured friction of the fiber supply. When raw material lots display high bundle cohesive force, spinners increase the roller spacing to prevent fiber breakage. Mechanical testing of sliver samples prior to spinning ensures that drafting remains within the optimal limits of the processing equipment.