Textile Inspection Machine: Matching Speed to Your Line

A catalogue says 80 m/min. Your line will not run at 80 m/min, and that is not a fault in either the machine or the line.

The number is a ceiling. It describes what the machine can handle when the fabric, the lighting and the tension all allow it. Your real speed is decided by what your fabric can take, and by how much time goes into everything that is not inspection.

This article separates the two, and gives you a way to estimate a shift before you order.

What is the difference between the ceiling and your speed?

The speed on the specification sheet belongs to the machine. The speed on your line belongs to your fabric.

Most buyers compare the first row and order against it. The third row is the one that decides payback.

Our ST-Thinkor textile inspection machine is specified up to 80 m/min across fabric widths of 1,800 to 4,000 mm. That is the ceiling. Everything below it is your calculation, and the rest of this article is about how to do that calculation before you order.

Does the machine have to run at your line speed?

No, and this is the first thing to settle. An off-line machine is decoupled from the weaving or finishing line.

Fabric is batched onto a roll at the loom, then inspected later, at whatever speed the fabric allows. Nothing in the process forces the two speeds to agree, so the inspection speed is yours to choose.

The in-line case is the opposite. The camera sits on the loom, so the fabric moves at loom speed and the inspection has to keep up with it. There is no second chance to slow the fabric down.

That difference decides where the machine goes. Your line speed and your inspection speed can differ, and an off-line machine keeps them independent.

An in-line machine suits the opposite priority. It catches the fault at the loom, before more metres are woven, and it takes the loom speed as its own.

Our ST-Thinkor-L runs in line with water-jet, air-jet and mending machines, and it inherits their speed rather than setting its own.

What speed can your fabric take?

Fabric decides the answer before the machine does. Two structural differences matter most, and both show up as soon as the fabric passes the first roller.

How do woven and knit fabrics differ?

A stable woven fabric holds its shape between the rollers. It can run close to the ceiling if the tension is set correctly at both ends.

A knit fabric keeps moving. The surface stretches and relaxes as it passes, so the same defect looks different from one metre to the next. Knit usually runs slower, and the limit comes from the fabric rather than the drive.

Why do tension-sensitive fabrics need to slow down?

Tension-sensitive fabric stretches when you pull it and relaxes when you stop. At inspection speed, that means the fabric width changes as it passes the camera.

A width that changes is a measurement that changes. If the fabric is 2% wider at the camera than it will be on the cutting table, every width and position figure carries that error.

The practical answer is to run slower, or to add a tension control that holds the fabric at a constant stretch. Slowing down costs throughput. Tension control costs money, and it takes up room on the floor.

Both are cheaper than discovering the problem after the fabric has been cut.

How much can a shift actually inspect?

This is arithmetic, and it is the part most quotations leave out.

Start with the speed you can actually hold. Then subtract everything that is not inspection: roll changes, threading, paperwork and labels.

The 40 m/min and the 3-minute change are placeholders. Put your own figures in and the table still works.

Note how much the changeover time costs. It removes nearly two hours from an eight-hour shift, which is 24% of the shift before a single defect is considered.

If the roll changes take five minutes rather than three, net output drops to 13,600 m. That is a 1,000-metre difference from a two-minute adjustment to a loading routine.

Ask your operators how long a roll change really takes, including the paperwork and the label.

One more subtraction belongs here. Some mills inspect twice, once on the greige roll and once after finishing. On that process the 14,640 m above covers both passes rather than each one, so compare the per-pass figure against your output.

What numbers should you have before you talk to a supplier?

Four numbers decide whether the answer you get is real, and all four come off your own floor.

· Your fabric width range, in millimetres, including the widest style you run.

· The speed you can hold on your slowest fabric, not your fastest.

· Your roll length, because it sets the changeover frequency.

· Your changeover time, measured rather than estimated.

If you want to compare how different models handle those four numbers, the range of fabric inspection machines is the place to start.

Bring those four to the conversation, and a supplier can give you a figure worth comparing instead of a catalogue maximum.

We cannot tell you what speed your fabric will allow. That comes from running your fabric, and it is why we ask for samples before quoting a number.

The other questions worth asking at this stage are covered separately: the common pitfalls in buying an automated inspection system.

Which speed figure to use

Three speed figures get used in the same conversation. One is on the specification sheet, one is what your fabric allows, and one is what leaves the inspection room after the changeovers are taken out.

Only the third can be compared between two quotations, because it is the only one that already contains your own changeover time. The other two are inputs, and neither says much about output on its own.

Two machines quoted at 80 m/min and at 60 m/min can post the same eight-hour total. The changeover time is usually what decides which of them does.