Woven Fabric Weight Tolerances and Linear Metre Yield Calculations
Reconcile woven fabric purchases by calculating linear yield from conditioned mass and usable cuttable width under ISO 3801 and ISO 139 parameters.
Dry Mass Desizing
Size Determination
Chemical extraction processes measure the percentage of sizing agents applied to warp yarns prior to weaving. Weaving mills perform dry mass desizing to quantify the amount of starch or polyvinyl alcohol present on the raw fabric. This test establishes the efficiency of the desizing stage, ensuring the fabric is clean and ready for dyeing.
It does not apply to synthetic fabrics that have not undergone warp sizing.
Extraction Step
The lab dry-weighs a fabric specimen before boiling it in an enzymatic bath to dissolve the sizing. After thorough rinsing, the specimen is dried again to constant weight in an oven. The difference between the initial and final dry weights represents the size mass.
This calculation reveals the exact chemical loading.
Process Control
Inadequate desizing leaves starch residues that block dye penetration, leading to patchy and uneven colouration. Measuring the remaining size after the industrial wash ensures that the desizing bath is running at the correct concentration and temperature. This prevents costly dyeing defects.
Yarn Protection
Warp yarns require a specific level of size, usually between six and twelve percent, to withstand the abrasion of high-speed weaving looms. If the dry mass desizing test shows values too low, the yarn may break frequently on the loom. Correct sizing levels are essential for weaver efficiency.