Fabric defect · Woven fabric - Selvedge defects in woven fabric

The selvedge is the woven edge on each side of the fabric, made stronger than the body so it stands up to weaving. A selvedge woven too tight or too loose makes the cloth wavy or keeps it from lying flat, and a loopy, curled or broken edge is a fault of its own. Some selvedge faults cause their trouble later, in dyeing and finishing.

An uneven, wavy edge along one side of woven fabric, outlined in cyan.

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.

On the defect map in the roll report, a selvedge defect is a line along one edge of the roll.

Fabric inspectionDefects, points and a final points forecast

What selvedge defects are

Goldberg's 1950 casebook defines the selvage as "the warp yarns woven at the extreme edges of a piece of fabric," usually denser than the rest of the warp or different in fiber, twist or ply, "to provide the greater strength needed for support in weaving" ¹.

A U.S. federal glossary lists bad selvages by kind: curled, folded or rolled; tight; loose; scalloped; wavy; stringy; corded, beaded, rough or loopy; cut or broken; and torn ². Most it calls "self-descriptive." A loopy selvage is "a selvage containing irregular filling loops extending beyond the outside selvages," and a cut or broken selvage has "cuts or breaks that occur in the selvage only and do not extend into the body of the cloth" ².

A wrong selvedge tension shows in the cloth beside it. Goldberg notes that goods with tight selvages sometimes "will not lie flat on the cutting table," and that "abnormally loose selvages, too, are undesirable" ¹. A 2012 U.S. military cloth specification has the inspector take the tension off the cloth and look for "a waviness in the selvage or significant ripples diagonally across the width of the fabric" ³.

What causes selvedge defects

Several of these causes involve parts of a shuttle loom.

What causes selvedge defects
Stage	What happens	What to check
Weaving	Loopy selvedges from waste caught behind the drop wires, too little tension on the yarn, or filling caught on the shuttle ¹.	Drop wires, filling tension and the shuttle
Weaving	A shuttle feeler that works badly can leave loopy selvedges or jerked-in filling ¹.	The shuttle feeler
Weaving	Damage on the side away from the shuttle box: a distorted selvedge with broken or partly cut picks, which later broke and ripped in finishing ¹.	The selvedge opposite the shuttle box
Construction	Selvedges too heavy for the body build up on the loom, which leaves a stretched or baggy center. In one case, edges with as many as four two-ply ends weaving as one broke where nip rolls pressed the wet goods; being all rayon, they also lost about half their strength wet ¹.	Selvedge weight and fiber against the body
Dyeing and finishing	Tight selvedges can cause oblique dye streaks from the edge, creases that will not come out in wet processing, or broken and torn selvedges if the strain is too great ¹.	Selvedge tension before the goods go to the dyer
Finishing	A selvage folded or doubled in finishing leaves a more or less regular mark along the selvage ².	Edge guiding through finishing

Where selvedge defects show on a roll

Selvedge defects lie along the edges of the roll. A cut or broken selvedge stays in the selvedge and does not reach the body of the cloth ². Tight selvedges can send dye streaks out from the edge at an angle ¹.

Some show away from the edge. A selvedge that is too heavy can leave a finished piece "with a stretched or baggy condition in the center" ¹, and uneven shrinkage, a wavy warpwise condition that keeps the cloth from lying flat, "may appear along one selvage or both selvages or through sections in the center of the cloth" ².

Defect positionWhat a defect's place on the roll points to

How selvedge defects count

A selvedge fault that runs on along the roll is a running defect. One buyer manual, which follows the 4-point system of ASTM D5430, gives up to 4 points to each linear yard or metre in which a continuous running defect exceeds 9 inches, and no linear yard gets more than 4 points ⁴. A short fault, such as a small cut in the selvedge, 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 ⁵. Check your buyer's manual for which selvedge faults it scores.

For military contract cloth, U.S. specifications score tight or loose selvedges at 4 points for each yard in which they occur ^{3, 6}. To find them, the 2012 specification has the inspector stop the perch "a minimum of three times for each roll in the sample, the tension removed," and look at the selvedges ³.

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 fabric shows selvedge defects most often?

Plan a pilot