Calibrating Optical Image Analysis for Overlapping Technical Flax Fiber Bundles
Optical image analysis of overlapping flax bundles demands controlled sample dispersion, distance transform segmentation, and microtome cross-sectional correction.
Cleavage Index
Separation Resistance
The physical measure of a flax bundle’s susceptibility to splitting along its longitudinal axis indicates the degree of retting and fibre division. This cleavage index evaluates how easily the pectin binder between individual flax filaments can be broken during mechanical hackling. High cleavage values suggest that the flax has been under-retted, which leaves the bundle too coarse for fine yarn spinning.
Low values mean the fibres are easily separated.
Laboratory Evaluation
Standardized testing procedures apply a wedge or tensile force to a clamped flax bundle to measure the cleavage index under controlled laboratory conditions. The result is recorded on the raw material quality sheet at the spinning mill to determine the blending ratios of the incoming flax bales. When the cleavage index is low, the flax divides easily during hackling, which yields finer yarn counts.
Conversely, a high index requires more intense mechanical processing that can break the delicate fibres. To avoid this, technicians adjust the hackling pins to apply gentler, incremental splitting forces that preserve fibre length.
Process Efficiency
Spinning performance relies heavily on achieving a consistent fibre division before the drawing frame. A low cleavage index reduces waste during hackling and drafting, which helps Chinese mills maintain high output rates of fine yarn. Processing coarse bundles with high cleavage values increases the frequency of yarn breaks on the ring frames.
This results in more loom stops and lowers the loom efficiency.