Extraction Ratio
Ratio of the mass of extracted fibre to the total input of raw straw as recorded during the first stage of mechanical processing. Commercial bast fibre decortication yield accounts for the removal of shives and woody core material. The value remains separate from subsequent scutching losses.
Mechanical Performance
Processing starts when dry flax straw passes through fluted rollers to break the crystalline woody interior. High bast fibre decortication yield indicates a successful separation where the bast bundles remain intact while the pith disintegrates. This value drops if the straw is too brittle or the roller pressure exceeds the bundle strength.
Precise adjustment of the roller gap is necessary to ensure that the fine fibres are not crushed during the impact. If the gap is too narrow, the yield of long fibre decreases as the bundles are severed into shorter pieces.
Economic Boundary
Mill profitability depends heavily on maintaining this ratio above a specific threshold defined by the moisture content of the input crop. When the bast fibre decortication yield falls below forty percent, the cost of processing the waste material often exceeds the market value of the resulting long fibre. Data from the intake sheet is used to calculate the final efficiency.
