Mechanical Function
Industrial textile machinery equipped with multiple pairs of speed-differential rollers attenuates and parallels carded flax slivers into uniform linear strands. This sliver preparation machine, known in spinning plants as a drawing frame, combines several card slivers and drafts them to improve fiber alignment and linear density uniformity. Sequential drafting passages blend variation out of raw fiber streams before roving and spinning operations.
Mill production logs record roller draft ratios and doubling numbers to ensure consistent sliver mass per unit length.
Drafting Process
Paired back and front draft rollers rotating at increasing surface speeds slide individual flax fibers past one another. Bottom steel fluted rollers combined with top rubber-covered pressure rolls grip the fiber bundle under spring or pneumatic pressure. Doubling six or eight card slivers at the entry creel averages out thick and thin places across the combined web.
Auto-leveling systems monitor output sliver thickness in real time, adjusting draft roller speeds automatically to correct weight fluctuations.
Operational Limit
Variable flax fiber lengths and coarse bundle ends cause drafting waves when roller gauge settings are improperly adjusted. Short fibers float uncontrolled between nip points, creating periodic thick spots in the drawn sliver. Excessive roller pressure crushes delicate flax bundles, generating fly waste and reducing average fiber length.
