Drafting Cohesion
Fibre alignment quality inside drawn slivers determines how uniformly parallel flax filaments remain before rove transformation occurs in Chinese spinning mills. Mechanical sliver drawing relies on roller speed differentials to straighten curled plant cells, and drafting cohesion measures the frictional resistance holding parallel strands together under drawing force. Excessive drafting friction causes fibre breakage during roller acceleration, whereas insufficient resistance creates thin sliver segments prone to breakage before twist insertion.
Mill supervisors record drafting cohesion scores on daily production logs during preliminary carding tests.
Roller Resistance
Slivers entering the drafting zone encounter paired steel cylinders rotating at accelerating surface speeds. Interfibre friction generates the necessary tension to pull overlapping filaments past neighbours without uncontrolled drafting breaks. When sliver density drops below established thresholds, drafting cohesion fails because inadequate contact surface area remains between adjacent filaments.
Machine operators adjust distance settings between drawing rollers to maintain uniform pressure across the sliver web.
Mill Thresholds
Internal mill standards differ significantly from external buyer acceptance criteria documented in export certificates. Spinning technicians establish internal drafting cohesion limits based on local machinery conditions and seasonal flax harvest variations. Export buyers inspect finished linen yarn strength rather than intermediate sliver properties, focusing on final tensile resistance instead of drawing mechanics.
Commercial transactions depend entirely on fabric grade compliance rather than mill processing parameters.
