Measuring defects - Where defects sit on a roll, and what that tells you

Every defect has two places: how far along the roll it is, and where it sits across the width. The pattern those places make, a line, a band, a repeat or marks near the edges, often points to the machine or the step behind it.

Four patterns on a roll: a line along it, a band across it, bars at an even spacing and marks near both edges, each outlined in cyan.

Two places for every defect

Each defect sits at a place along the roll and at a place across the width. Record which end of the roll the metres count from, which selvedge the width is measured from and which face was up, since rewinding turns a roll end for end. One buyer manual has every defect marked with a sticker at the defect, or with a marker at the selvedge edge ¹.

Patterns and what they point to

Each row is a pattern inspectors meet, with the causes the sources tie to it.

Patterns and what they point to
Pattern on the roll	What it often points to	Defects
A line along the warp at one place across the width	Damaged reeds, whose uneven spacing of the warp ends leaves streaks through full pieces ²; a wrong draw through the heddles, such as two ends weaving as one ²	Reed marks, Broken ends, Floats
A line along a wale in knit fabric	Worn needles, which "generally produce length direction streaks" ³; needles that are bent or damaged, or come from different suppliers ⁴; loops that unravel one by one down the wale ⁵	Runs and ladders, Needle lines
A band across the full width	Full bobbins of mixed filling ²; uneven pickage from take-up and let-off ²; a loom stop, after which the first picks beat up too sparse or too dense ⁶	Filling bars, Starting marks, Mispicks
Bars along the courses of circular knit fabric, often repeating	Yarn differences, or the stitch length or tension at one feed ³; on a single jersey machine one turn knits a course for each feed ⁷	Barre
Marks near the edges	Loom temples grip the cloth for about 4 inches on either edge ²; coarse or dull temple pins left small holes reaching about 4 inches in from one selvedge ²	Holes, Temple marks, Selvedge defects
Marks that repeat at an even spacing	A regular repeat points to a machine part, and a spacing that grows or shrinks to damage while the fabric was rolled up ²; uneven harness tension gives repeat marks in the weave ²	Holes, Filling bars
Scattered spots	Neps, which make short thick places in yarn ⁸; contamination such as organic matter and plastic in the cotton ⁹	Slubs, Neps, Foreign fibers
Spots or bands that show only after dyeing	White specks from tangles of immature fiber that take no dye ¹⁰; uneven pickage, which shows as narrow bands once dyed ²; dye differences in the yarns, one source of barre ³; plastic, whose damage shows only after final finishing ⁹	Filling bars, Barre, Neps, Foreign fibers

The map of the roll

A roll report can carry a map of the roll with each confirmed defect at its place. A pattern that is hard to see in a list of defects stands out on a map.

The example roll on our fabric inspection data page has half of its 20 defects between 60 and 80 metres, a cluster a map shows at a glance. To trace a cluster, work out when that stretch was made, then look at the stops, yarn changes and shift changes around that time.

Greige and finished inspection

Some defects show only after dyeing, so a mill that inspects only greige fabric meets them later. Goldberg notes that uneven pickage is not always easy to see in greige goods and shows once the goods are dyed and finished ². White-speck neps appear in dyed fabric because their immature fiber takes no dye ¹⁰.

What ConductVision Textile records

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.

For each roll it is designed to give a roll inspection report with every confirmed defect, the roll's totals and a line for your inspector's decision, and a map of the roll with its defects marked.

Fabric inspectionDefects, points and a final points forecast

Sources

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 pattern on your rolls would you most like to trace?

Plan a pilot