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Fabric defects - Fabric defects: a library of woven and knit defects

Each page covers one defect: what it is, what causes it, where it shows on a roll and how it counts, with its sources. The measuring pages cover size, position, the roll report, the roll forecast and the other grading systems.

Woven fabricKnit fabricYarnDyeing and printingFinishingHoles, threads and stainsMeasuring defects
A close view of blue denim, showing the diagonal lines of its weave

Woven fabric

Filling bars

Woven fabric

Picks that differ from the rest in thickness, number or yarn. A band across the roll.

See filling bars 

Mispicks

Woven fabric

A pick woven out of order, missing or doubled. A line across the roll.

See mispicks 

Broken ends

Woven fabric

A warp yarn that breaks, or is missing for part or all of the cloth. A line along the roll.

See broken ends 

Reed marks

Woven fabric

A streak along the warp where the ends are spaced unevenly, most often from a damaged reed. A line along the roll, often through the whole piece.

See reed marks 

Floats

Woven fabric

A warp or filling yarn left unbound over yarns it should interlace with. A short line along or across the roll.

See floats 

Starting marks

Woven fabric

A band across the fabric where the loom stopped and started again. A narrow band across the roll.

See starting marks 

Selvedge defects

Woven fabric

An edge of the fabric woven too tight or too loose, or left loopy, curled or broken. A line along one or both edges of the roll.

See selvedge defects 

Temple marks

Woven fabric

Holes, marks or streaks near the edge of the cloth, left by the loom's temples. A line of marks along the roll, a few inches in from an edge.

See temple marks 

Denim fabric defects

Denim

Defects in denim, by the stage that makes them: yarn, indigo dyeing, sizing, weaving and washing. Spots, lines along or across the roll, and bands.

See denim fabric defects 

Knit fabric

Barre

Circular knit fabric

A repeating pattern of bars or stripes, from differences in yarn or knitting. Bands across the roll, often at an even spacing.

See barre 

Runs and ladders

Knit fabric

Stitches that unravel down a wale. A line along the roll.

See runs and ladders 

Dropped stitches

Knit fabric

A stitch left unknit, where a needle failed to form its loop. A spot, or a line along the roll.

See dropped stitches 

Needle lines

Knit fabric

A lengthwise line in a knit that follows one wale. A line along the roll.

See needle lines 

Press-offs

Knit fabric

Some or all of the needles on a circular knitting machine stop knitting. A large hole, or a line across the roll.

See press-offs 

Elastane faults

Knit fabric

Faults in the stretch yarn of a knit. Stretch yarn missing, or stretch lost in finishing.

See elastane faults 

Spirality

Knit fabric

Wales that lean, so knit fabric twists. A slant in the wales that grows after washing.

See spirality 

Yarn

Slubs

Spun yarn, in woven and knit fabric

A short, thick place in the yarn. A spot along one yarn on the roll.

See slubs 

Neps

Cotton yarn, in woven and knit fabric

Small tangles of fiber that show as specks, often white ones after dyeing. Scattered spots, often seen only after dyeing.

See neps 

Knots

Spun and filament yarn, in woven and knit fabric

A small lump where two yarn ends were tied together. A spot on one yarn.

See knots 

Thick and thin places

Spun and filament yarn, in woven and knit fabric

A stretch of yarn or fabric thicker or thinner than the rest. A streak along one yarn, or a band across the roll.

See thick and thin places 

Foreign fibers and contamination

Yarn and fabric, woven and knit

Fibers or matter that do not belong, spun into the yarn or woven into the fabric. Specks, short streaks or slubs, often seen only after dyeing.

See foreign fibers and contamination 

Dyeing and printing

Dye spots and chemical stains

Dyed and finished fabric

A spot of unwanted color, or a stain left by a chemical, from dyeing or finishing. A spot on the roll, sometimes a short streak.

See dye spots and chemical stains 

Crease marks and rope marks

Woven and knit fabric

A line set into the fabric where it was folded, pressed or twisted. An irregular line on the roll.

See crease marks and rope marks 

Water spots

Dyed, printed and finished fabric

A spot or mark left where water reached the fabric, in the mill or later in use. A spot on the roll.

See water spots 

Printing defects

Printed fabric

Faults in a printed pattern: colors out of register, streaks, smears and missing color. A spot or a streak along the roll, sometimes repeating at a regular interval.

See printing defects 

Uneven dyeing

Dyed fabric and yarn

Color that is not the same all through the cloth. Streaks, blotches or specks.

See uneven dyeing 

Shade variation

Dyed fabric

A change in shade where the fabric should match. Side to center, end to end, or roll to roll.

See shade variation 

Finishing

Bow and skew

Woven and knit fabric

Filling yarns or knit courses that arc, or run off square to the length of the fabric. A curve or a slant across the roll.

See bow and skew 

Holes, threads and stains

Holes

Woven and knit fabric

An opening where yarns have broken or been cut. A spot on the roll.

See holes 

Loose threads

Woven and knit fabric

A yarn end or loop lying on the face of the fabric. A spot on the roll.

See loose threads 

Snags and pulled threads

Knit and woven fabric, mostly filament yarn

A yarn pulled out of place by a sharp point. A spot on the roll.

See snags and pulled threads 

Oil stains and grease spots

Woven and knit fabric

Machine oil or grease on the fabric, or worked into its yarn. A spot, or a line along or across the roll.

See oil stains and grease spots 

Measuring defects

Defect size

How a defect's length sets its points

The 4-point bands in inches and centimetres, the hole rule, running defects and points per area.

See defect size 

Defect position

What a defect's place on the roll points to

What a line, a band, a repeat or marks near the edges point to.

See defect position 

Fabric inspection report

What each roll's report holds

What a buyer expects on each roll, with a sample report.

See fabric inspection report 

Roll forecast

A roll's likely final points against your limit

The points a roll is likely to end with, read against your buyer's limit.

See roll forecast 

Four-point system

How fabric inspection points work

The point scale, the cap per linear yard and a calculator for points per area.

See four-point system 

Fabric grading systems

How the other point systems score defects

How the 10-point, Graniteville "78" and Dallas systems score defects, beside the 4-point system.

See fabric grading systems 

Fabric inspection data, explained

A worked example roll

Where the defects sit, how the points add up and how two forecasts read.

See the worked example 

ConductVision Textile

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. ConductVision Textile does not measure bow, skew, width or shade.

See fabric inspection

What research says

A 1992 paper on machine inspection of fabric estimated that a human inspector notices perhaps 60 percent of the defects present 1. An Oak Ridge National Laboratory report gives as background that in manual inspection "Many defects are missed, and the inspection can be inconsistent" 2. A 2008 paper set out to give the first survey of automated fabric defect detection 3.

How defects count on a roll

Under the 4-point system, a defect's points depend on its size. ASTM D3990 holds the standard terms for fabric defects 4.

Sources

  1. 1L. Norton-Wayne, M. Bradshaw and A. J. Jewell, Machine vision inspection of web textile fabric, British Machine Vision Conference (1992)
  2. 2H. Sari-Sarraf and J. S. Goddard, Oak Ridge National Laboratory, OSTI 654034
  3. 3A. Kumar, Computer-vision-based fabric defect detection: a survey, IEEE Transactions on Industrial Electronics 55(1), 348-363 (2008)
  4. 4ASTM D3990, Standard Terminology Relating to Fabric Defects

Pilot - How a pilot starts

We start with recorded video of your inspection frame and agree with your team on one fabric to test. The pilot runs for a set time, and before it starts we agree on what counts as success. For each defect it marks, ConductVision saves a still image and its place on the roll on your network for your inspector to check.

You bring
Recorded video of fabric running over your inspection frame
We set up
One fabric, and the limit you grade it against
You get
Marked defects, running points and a final points forecast for each roll, and a results report checked against what we agreed

One question to start with

Which fabric gives your inspectors the most trouble?

Plan a pilot

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