Attenuation Resistance
Physical forces resisting the sliding of individual fibers against one another during the thinning of a sliver or roving define the mechanical behavior of the material. In the context of spinning, drafting friction determines how much force the rollers must apply to stretch the bundle into a finer strand. This resistance influences the evenness of the final yarn.
Fiber Interaction
Surface characteristics of the flax fiber and the presence of residual gums dictate the level of drag between neighboring strands. When drafting friction is too high, the fibers do not slide smoothly, causing thick and thin spots in the yarn. Conversely, low resistance allows fibers to slip uncontrollably, leading to breakages.
Natural waxes and added lubricants modify these forces to keep the drafting process stable.
Drafting Control
Mechanical settings on the spinning frame must account for the specific coefficient of friction of the batch. Rollers apply pressure to grip the fiber bundle while the difference in speed between the front and back sets creates the draft. If the drafting friction varies widely within a single lot, the resulting yarn will show periodic irregularities.
Managing this force requires consistent humidity in the spinning room and precise application of spin finishes. The interaction between fiber length and surface roughness determines the optimal pressure for the drafting zone.
