Warp Sizing
The dry size add on percentage quantifies the mass of starch or polymer coating that remains fixed to warp yarn after the solvent evaporates within a industrial slash chamber. It defines the weight ratio of solid bonding agents to the base flax fibres before the warp enters the loom for mechanical insertion. Mills calculate this figure by comparing the weight of a bone dry yarn sample taken before the slashing process to the weight of a sample removed after the drying cylinders complete their heating cycle.
Precise control over this measurement prevents yarn breakages during high speed shed formation. Consistent levels ensure the protective film adheres firmly to the individual fibres without causing excessive stiffness that leads to brittleness. Over application creates thick crusts that flake off and contaminate the air, while insufficient coverage leads to fraying at the reed.
Application Threshold
Operators determine the success of this metric by evaluating how the size film protects the brittle flax fibres against the repeated friction of metal heddles and shuttles. A specific percentage provides the required tensile strength to withstand the loom environment while preserving enough flexibility for clean separation. Excess deposit accumulates on machine parts and blocks the air circulation that keeps the yarn at a set temperature.
Low readings result in increased hairiness and warp stops that interrupt production cycles. Technicians use manual moisture balances to verify that moisture content stays below the baseline before they record the final dry size add on percentage for the batch. This verification step separates the weight of the added chemical solids from the residual water held by the cellulose.
Quality Standard
Buyer contracts specify these limits to guarantee the uniformity of the cloth surface appearance and handle. Factories document the final values on each lot technical report to prove adherence to agreed upon chemical thresholds. Flax mills maintain these records as part of the traceability logs that track fibre preparation from the initial soaking vats through to the final rolled fabric.
Differences in raw material quality necessitate constant adjustment of the input chemical concentration to maintain an identical finish. High concentrations improve abrasion resistance but often diminish the natural aesthetic appeal of the final textile product.
