Knit Fabric Quality Control

Quality monitoring: Online detection—drop stitches (hole detection via optical sensors stopping machine, integrated in modern circular knits monitoring 100% production), yarn tension monitoring (preventing tight loops, slubs, thick places), and fabric take-down tension (maintaining consistent GSM, width). Offline inspection—fabric relaxation (allowing loops to settle, typically 24 hours before measurement), dimensional measurement (width, GSM verification against specifications ±5% tolerance), and visual inspection (grading defects per 4-point system). Common defects: Drop stitches/holes (needle malfunction, yarn break—most serious, rejectable), horizontal bars/lines (tension variation, machine stoppage marks, machine setting issues), vertical streaks/wales (needle damage, uneven yarn tension in feeders), contamination (fly, oil spots, foreign fibers), and dimensional issues (GSM variation, width variation, excessive shrinkage). Quality standards: first quality <20 points per 100 m², second quality 20-40 points, rejectable >40 points per 100 m² (textile industry standard modified for knits considering structure complexity).