Measuring defects - Measuring fabric defects: size and points

Under the 4-point system, a defect's size sets its points. Here are the bands in inches and centimetres, the rules for holes and running defects, and how a roll's points become points per area.

Three defects of different lengths, and one running defect that crosses yard lines, each outlined in cyan.

Points by length

The 4-point system scores a defect by its length. One buyer manual that follows it as ASTM D5430 prints the bands in inches and in centimetres ¹.

Points by length
Length in inches	Length in centimetres	Points
Under 3	Under 8	1
Over 3, under 6	Over 8, under 15	2
Over 6, under 9	Over 15, under 23	3
Over 9	Over 23	4

One trade guide words the bands as up to 3 inches, over 3 up to 6, and so on ². Our four-point guide uses the same wording, so a defect of exactly 3, 6 or 9 inches falls in the lower band. The centimetre edges are rounded, so a defect near an edge can fall in a different band in centimetres than in inches. Grade in the unit your buyer's manual uses.

Holes

The same trade guide scores a hole of 1 inch or less at 2 points and a larger one at 4, by the hole's largest dimension ². Buyers differ on holes: one study of knit fabric scored any hole except a pinhole at 4 points ³. Your buyer's manual sets the rule. Rules like these go by what the defect is as well as its size, so the name your inspector gives a defect can change its points.

Running defects

A running defect continues along the roll, as barre or a run can. One buyer manual gives up to 4 points to each consecutive linear yard or metre in which a continuous defect runs past 9 inches, or 23 centimetres. No linear yard or metre gets more than 4 points, however many defects it holds ¹.

From points to points per area

Rolls differ in length and width, so mills compare them by area. Points per 100 square yards are the roll's points times 3,600, divided by the yards inspected times the cuttable width in inches. Points per 100 square metres are the points times 100,000, divided by the metres inspected times the cuttable width in millimetres ¹.

Take the example roll on our fabric inspection data page: 30 points over 100 metres of fabric 1.5 metres wide. That is 30 × 100,000 ÷ (100 × 1,500), or 20 points per 100 square metres.

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.

It is designed to measure each defect along its longest dimension and to give no linear yard more than 4 points.

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 fabric and which buyer's limit would you test first?

Plan a pilot