Determining Flax Staple Profile Using Manual Comb Sorting
Manual comb sorting by ISO 2370 isolates technical flax bundle length profiles to prevent drafting waves, control short fibre content, and enforce purchase contracts.
Shive Impurity Load
Contamination Level
Non-fibrous plant matter represents the proportion of waste material present in a raw flax delivery. The shive impurity load consists of woody fragments from the core of the flax stalk that were not removed during the initial extraction. High levels of these particles interfere with the subsequent spinning processes.
A sample is typically weighed before and after manual cleaning to determine this percentage.
Cleaning Requirement
Excessive amounts of woody matter require more intensive carding and hackling to produce a clean sliver. If the shive impurity load is too high, the mechanical action needed to remove it can damage the valuable long fibres. This trade off often leads to a lower yield of high grade material.
Modern cleaning machines use optical sensors to identify and eject these dark particles. A heavy load forces the mill to use multiple passes of cleaning, which increases labour costs and energy consumption. This extra handling can also lead to more fibre breakage.
Grade Assessment
Buyers use the purity of the fibre as a primary indicator of its market value. A low shive impurity load is characteristic of premium flax suitable for fine yarn production. Materials with high impurity levels are diverted to coarser products such as twine or heavy canvas.
Quality reports always include this metric to justify the pricing of a lot.