Speed Differential
Roller surface velocity comparisons quantify mechanical strand elongation across consecutive drawframe drafting zones. Machinery settings define drafting ratio as the quotient of front delivery roller speed divided by back feed roller speed. This operational parameter governs linear density reduction from heavy card sliver down to fine roving.
Yarn count targets determine the required velocity acceleration across draw stages.
Strand Attenuation
Attenuation of wet-spun flax slivers requires precise mechanical speed differences between nip points to separate overlapping fiber bundles. When back rollers feed sliver at low speeds into high-speed front rollers, individual technical fibers slip past each other, distributing linear mass evenly along the strand length. Multi-stage draw frames employ cumulative speed multipliers across three or four sequential drafting heads to reach total attenuation levels exceeding one hundred.
Incorrect speed ratios create severe strand irregularity, generating periodic thick and thin places known as drafting waves. Processing plant technicians lock roller drive gear ratios according to fiber length distribution records to prevent roller slip and fiber grouping during draft application.
Production Record
Production control sheets record feed and delivery velocity settings for every drawframe lot. Excessively high ratios trigger strand breaks during wet spinning. Mechanical draft calculations lose relevance after false twist insertion locks fiber positions permanently against further slip.
