Flax Cell Wall Microfibril Alignment Determination Methods
X-ray scattering and polarized Raman spectroscopy determine flax microfibril angles to project spinning performance and yarn tenacity.
Draw Ratio
Extension Proportion
Linear speed differentials between the feed and draft rollers determine the degree of attenuation and parallelization applied to the fiber sliver during spinning. Setting a higher draw ratio forces the flax fibers to slide past each other, which reduces the linear density of the resulting yarn. This mechanical draft is essential for transforming thick, coarse slivers into fine, uniform linen yarns.
The draft must be carefully matched to the mean fiber length to prevent creating thick and thin defects known as drafting waves. In wet spinning, this process is facilitated by hot water in the trough, which softens the pectin binders and allows the individual elementary fibers to slide without fracturing the bundles.
Mechanical Adjustment
Drafting adjustments on wet spinning frames control the final yarn count and the cohesion of the drawn fibers. If the draw ratio is set too high for a given flax grade, the excessive tension causes frequent breaks in the drafting zone and increases machine downtime. Conversely, a draft that is too low produces heavy, lumpy yarn with poor weaving characteristics.
Operators must calibrate the roller settings and speeds based on the dampness of the fiber and the quality of the pectins.
Production Outcome
Spinning supervisors monitor the output weight per unit length to verify that the drafting system operates correctly. Proper draft regulation ensures that the yarn meets the exact specifications of the weaver for warp or weft density. This consistency is vital for preventing visible horizontal bands in the finished linen fabric after bleaching.
Precise drawing controls thus support both yarn yield and fabric appearance.