Fabric defect · Knit fabric - Elastane faults in knit fabric: causes and checks

ConductVision Textile is designed to flag each defect with its place on the roll, its size, its points and a still image. Your inspector names the defect and confirms or dismisses it.

On the defect map in the roll report, an elastane fault is a line across the width, along a course.

U.S. rules call the fiber spandex, a manufactured fiber of at least 85 percent segmented polyurethane ¹, and EU rules call it elastane ².

Spandex goes into cotton fabrics for more stretch and recovery than cotton gives alone, in knit goods such as skirts, leggings and tops. A cotton knit may carry it in every course or in alternating courses, as bare spandex plated with the cotton, core-spun inside a cotton sheath, or covered by cotton fibers ³.

One study of a knit factory counts a fault in which the elastane is out of the fabric ⁴.

Elastane runs along the courses of a knit, in every course or in alternating courses ^{3, 5}. A course that lacks it is a line across the width.

Two faults in cotton and spandex knits come from heat setting rather than from the elastane itself. A slit tube leaves a center line where it was folded, which heat setting makes permanent unless it is removed first, and a tube rolled flat for heat setting in an autoclave can have its edges set for good ³.

An elastane fault is scored by its length: 1 point up to 3 inches, 2 points over 3 up to 6 inches, 3 points over 6 up to 9 inches and 4 points over 9 inches ⁶. A course without elastane crosses the width, so it scores 4 points. Under the 4-point system, no linear yard or metre gets more than 4 points, however many defects it holds ⁷. A fault that repeats through a whole roll can cost 4 points in every yard.

Cotton Incorporated's grading guide says the purchaser and the supplier must agree on the list of defects used in grading and on their severity ⁷. Settle with your buyer how elastane faults count.

A 2018 study followed the finished knit fabric of one factory in Bangladesh for 12 months, across single jersey, rib, interlock, fleece and other knits, with and without elastane. A Pareto analysis put the elastane fault among five defects, with holes, contamination, dirty spots and oil spots, that made up 90 percent of all defects ⁴.

The authors traced each major defect with a cause and effect diagram. For the elastane fault, every cause they list sits at the elastane feed or in the elastane yarn itself ⁴.