Fabric Defects: Types, Causes and How They Are Found

A practical guide to common woven and knitted fabric defects: yarn defects, weaving and knitting defects, dyeing and finishing defects, and dimensional problems. What each looks like, where it comes from and how it is detected.

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Fabric defects are faults in the fabric itself, as opposed to faults made during cutting and sewing. They come from the yarn, the weaving or knitting process, or dyeing and finishing. Finding them before cutting is much cheaper than finding them in finished garments.

Defect What it looks like Typical source
Slub Thick place in the yarn, a short raised lump Spinning faults, fly waste spun in
Nep Tiny tangled fiber knots, often showing as white specks after dyeing Immature cotton, carding
Thick and thin places Yarn diameter varies along the length Drafting faults in spinning
Contamination Colored or foreign fibers Mixing, polypropylene from bale packing
Knots Visible knot in the fabric Yarn joining

Knitting defects#

Defect What it looks like Typical source
Barre Horizontal bands of different shade or texture Yarn lot mixing, count or tension variation between feeders
Hole A hole, sometimes with a run Broken needle, yarn break, high tension
Drop stitch Missing loop, can run into a ladder Needle latch fault, yarn feed
Needle line Vertical line along a wale Damaged or bent needle
Sinker line Vertical line from a damaged sinker Worn sinker
Spirality Wales slant diagonally Yarn twist liveliness, machine, relaxation

Weaving defects#

Defect What it looks like Typical source
Missing end A warp yarn missing along the length Warp break not repaired
Missing pick A weft yarn missing across the width Weft stop failure
Float Yarns floating over an area without interlacing Broken warp threads, heald faults
Reed mark Lengthwise streak Damaged reed
Starting mark Crosswise band at a loom restart Loom stop and restart

Dyeing and finishing defects#

Defect What it looks like Typical source
Shade variation Color differences side to side, end to end or between rolls Dyeing process variation
Uneven dyeing Patchy color Poor preparation, dye strike rate
Crease marks Permanent lines Fabric folded under heat or in dyeing
Stains and spots Oil, dye or dirt marks Machinery, handling
Bowing and skewing Weft or courses not straight across the width Stenter feeding, uneven tension
Excessive shrinkage Dimensions change after washing Insufficient relaxation or compaction

Detecting fabric defects#

  • Visual inspection on an inspection frame using the 4-point system.
  • Shade checks between rolls, and within rolls from center to selvedge and end to end, in a light box.
  • Physical tests: GSM, shrinkage, bow and skew, spirality, color fastness, pilling.
  • Blanket or shade band comparisons across dye lots.

Dealing with defects at cutting#

  • Mark defects at inspection so spreaders can see them.
  • Cut around defects where the marker allows, or replace defective panels.
  • Group rolls by shade and cut each shade group separately.
  • Record defects found at cutting and report them to the supplier.

See fabric spreading for defect handling during spreading, and sewing defects for faults made in sewing.

Frequently asked questions#

Who pays for fabric defects found at cutting? That depends on the supply contract. Record defects with photos, roll numbers and quantities, and report them to the supplier promptly.

Can a fabric pass 4-point inspection and still cause problems? Yes. The score covers visual defects only. Shrinkage, shade between rolls, bow and skew need their own checks.

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