Visual Width
Non-contact measurement of yarn thickness during winding is performed by scanning the shadow cast by the thread as it passes a light source. Sensors on winding machines measure the optical profile width of the yarn to detect thin spots and thick slubs in real time. This continuous scanning prevents yarn defects from being introduced into the fabric.
Projection Measurement
Infrared light-emitting diodes cast a continuous beam across the path of the yarn onto a high-speed photodiode receiver. As the yarn vibrates or twists, the optical profile width can change slightly, but the averaging software filters out these minor movements to calculate the true average yarn diameter. This ensures the measurement remains stable even at high winding speeds.
Blending Control
Blending operations depend on uniform yarn thickness to prevent the formation of visible bands in the knitted or interlaced fabric. If the optical profile width indicates that the yarn has drifted from the targeted specification, the machine operator can halt the process to check the blending ratios of the synthetic and natural fibres. This early detection saves the mill from wasting expensive raw materials, and it prevents the production of second-grade fabric that would have to be sold at a loss.
Yarn Consistency
Fabric mills use this continuous thickness data to assess the warp yarn quality before starting the looms. If the yarn has a highly variable optical profile width, it is more likely to snag on adjacent threads during shedding. This step prevents loom stops and defects in the cloth.
