Abrasion Test Pair Cycles to failure, unsized and sized

Unsized Yarn cycles

Sized Yarn cycles

Size Add-On on the Tested Yarn %

Abrasion the Loom Demands cycles

From a machine that runs this fabric acceptably

Hairiness & Economics What the size film does, and what it costs

Hairiness Before Sizing S3/m

Hairiness After Sizing S3/m

Warp Sized t/yr

Size Solids Cost /kg

Add-On Above What the Loom Needs

— %

Negative means the yarn is under-sized for this loom

Abrasion Gain, Weavability & Cost of Over-Sizing

Add-On That Just Meets Demand: — %
Weavability Index: — x
Abrasion Improvement: — x
Cycles Gained per Point of Add-On: — cycles/%
Hairiness Reduction: — %
Size Solids Saved: — kg/t
Size Solids Saved: — kg/yr
Value of the Surplus: — /yr

The slope is a chord between two measured points and is only reliable near the tested add-on; abrasion resistance against add-on saturates, so extrapolating far below the tested point understates the true resistance and far above it overstates it. Abrasion cycle counts are highly variable specimen to specimen - coefficients of variation of 20 to 30% are normal - so both figures should be means of at least twenty breaks, and a difference smaller than the scatter is not a difference. The demand figure is specific to a machine group and a construction and must be re-established when either changes. Hairiness reduction is reported from the values entered and is not used in the add-on arithmetic; it is the second reason sizing exists and it saturates at a different add-on than abrasion does. Nothing here accounts for size recipe: a change of polymer at constant add-on can move the abrasion figure more than a two-point change of quantity.

Sized Yarn Abrasion Resistance, Hairiness Gain & Add-On Adequacy — free, with the formula and a worked example, at Textile School.