Fabric Inspection Machine

Overview

A fabric inspection machine is the quality gate between fabric production (or receipt) and the cutting room. It rewinds a roll of fabric from one end to the other past a lit viewing screen at a speed an inspector can scan, typically 15–25 m/min for full inspection, while measuring the delivered length, keeping the edges aligned, and recording every defect the inspector flags with its type, severity and metre position. The output is an inspected, accurately measured, evenly wound roll plus a defect report that lets the garment maker grade the roll under the four-point system (ASTM D5430) and lets the cut planner work around faults instead of discovering them in cut panels.

The machine itself adds nothing to the fabric; its engineering problem is transporting a delicate web at constant low tension, in both directions, without stretching it, knits especially can elongate several percent under modest tension, which would corrupt both the length measurement and the garment.

How it works

The incoming roll sits in the Unwind Unit, either on a driven Unwind Cradle for soft or tubeless rolls or on an expanding Unwind Shaft, and pays off through a weighted Dancer Arm arm whose position trims the drive, smoothing the tension transients of starts, stops and reversals. A bowed Spreader Roller roller pulls out creases and presents the web flat.

The fabric then climbs the Inspection Screen, an opal panel inclined toward the inspector and lit two ways: Backlight Tube tubes behind it make holes, thin places, missing ends and slubs show as bright or dark spots in transmitted light, while Top Light tubes show surface faults, stains, snags, shade bars, in reflected light. The Lamp Driver runs the LEDs above 20 kHz so no flicker beats against the moving cloth; for colour-critical work D65 tubes are fitted. Standing on the Inspector Platform, the inspector controls speed, stop, creep and reverse from the Footswitch, keeping both hands free.

When a defect appears, the inspector keys its type and severity on the Defect Keypad and triggers the Sticker Applicator, which fires an adhesive flag onto the selvedge level with the fault so it remains visible on the edge of the finished roll. The controller logs each entry against the running length from the Measuring System system, whose calibrated Counter Wheel rides the fabric and turns an Encoder; because the wheel contacts the cloth directly, the measurement is true delivered length, unaffected by roller slip, to about ±0.2 %. A Width Sensor can log usable width along the roll for the marker planner.

Winding is handled by the Rewind Unit: an inverter-fed Rewind Motor whose torque the Drive Control tapers as the roll grows, so web tension stays constant from core to full diameter, with a Lay-On Roller pressing out trapped air. Ahead of the winder, the Edge Guiding System keeps the roll straight-sided: infrared Edge Sensor forks read the selvedge position and the Guide Actuator pivots the Correction Frame to steer the web, holding edge alignment within 2–3 mm. For knits, Edge Uncurler scrolls open the curled selvedges first.

Grading and reporting

Under the four-point system the inspector assigns 1–4 penalty points per defect by length, with a maximum of 4 points per linear yard; rolls scoring over a threshold (commonly 40 points per 100 square yards) are rejected or re-graded. The Control Board compiles the defect log into a roll report, total points, points per 100 sq yd, defect map by metre, and prints the roll ticket with the certified length. The defect map is increasingly exported to cutting-room software, which nests panels around flagged zones.

Variants

The same transport platform carries several upgrades: tubular-knit versions with basket unwinds and folders, denim machines with heavier 600 mm rolls, and automated visual inspection systems that replace the human with line-scan cameras over the screen, detecting defects at 100 m/min and writing the defect map directly. Doubling-and-rolling machines combine inspection with folding fabric to half width. Throughput for manual inspection is governed by the human, not the machine: sustained reliable detection caps near 25 m/min, which is why camera systems are displacing manual screens in high-volume mills.