Gravimetric Testing Basics for Hackled Line Flax Sliver
Gravimetric testing determines hackled flax sliver dry mass, moisture regain, and linear density to lock in fair commercial yarn pricing.
Gilling Waste
Drawing Residue
Short fibres and tangled bundles ejected during the hackling and drawing processes represent a direct loss of raw material in the spinning mill. In yarn preparation, gilling waste consists of flax fibres that are too short to be drafted into the sliver. The weight of this discarded material is recorded on the daily carding report to track the efficiency of the preparatory machinery.
Fiber Loss
Fibre length distribution determines the amount of material rejected during the drawing passes. When raw flax has been poorly retted, the fibres break more easily under the action of the faller pins in the gill box, leading to a higher volume of gilling waste. Spinning mills try to keep this loss below five percent of the input mass to maintain profitable production margins.
Technicians check the accumulation boxes regularly to ensure that the drafting rollers are not misaligned or running at excessive speeds. These measurements are necessary for calculating the yield of high-grade sliver and are reviewed during weekly production meetings.
Efficiency Coefficient
High waste ratios indicate that the incoming flax fiber grade is too low for the intended yarn count. Production managers use these weekly records to adjust the buying price or to switch to a different fibre supplier. The resulting cost adjustment is documented in the mill’s monthly operating ledger.