Reconciling Mill Loom Shed Records for Customs Non Preferential Provenance Files
Non-preferential linen origin relies on matching raw yarn lots to loom shed operator tickets, proving substantial transformation through verified machine capacity.
Picks per Inch
Density Metric
Fabric density along the longitudinal warp plane is quantified by counting the individual transverse yarns inserted across one linear inch of interlaced cloth. The numerical specification of picks per inch defines cloth compactness, square meter mass, tensile strength, and structural firmness in unfinished and finished linen textiles. In industrial flax processing, this construction parameter is established at the cloth formation zone and verified across greige inspection benches and finished inspection tables.
The metric ceases to apply to nonwoven flax mats, knitted structures, or unbonded unidirectional roving sheets.
Loom Setting
Mechanical take-up motion regulates the rate at which formed fabric advances away from the beat-up point, thereby fixing the spacing between consecutive weft insertions. Mill technicians set change gears or program digital servomotors on rapier or air-jet looms to obtain the target picks per inch specified in the cloth design sheet. Real-time monitoring verifies insertion frequency against the main drive shaft rotation to prevent density variations caused by slip or let-off tension anomalies.
Offloom inspection sheets record actual pick count using an optical pick glass across three distinct zones across the usable width. Minor deviations in raw yarn diameter create apparent optical variations even when the mechanical pick count remains constant. If the take-up mechanism drifts from the nominal setting, the resulting pick density variance alters fabric weight and induces uneven dye uptake during piece dyeing.
Shrinkage Calculation
Downstream chemical finishing and rotary washing compact the weft yarn spacing through dimensional relaxation and yarn swelling. Finishing plant batch records list both greige picks per inch and post-finishing target counts to verify that target dimensions match purchase specifications.
Calculating Plain Linen Target Weight from Yarn Count
Target linen weight equals yarn tex multiplied by thread density, adjusted for warp size, crimp, wet process mass loss, and area shrinkage factors.