Optical monitoring of a fiber strand for quality control in yarn production uses reflected light for successive determination of yarn diameter and impurities

摘要

Reflected light (11) from a fiber strand (1) provides a signal (M) from a line sensor (14) that is analyzed to first measure the diameter and then identify any impurities. The signal from each sensor cell is compared with a reference value and if the difference exceeds a limiting value a fault signal is given. A predetermined number of faults trigger a process intervention. An independent claim is also included for the apparatus comprising a light source (4), optics (12), sensor (14), and control and computing electronics (17) to provide a control signal for strand diameter (SD) and for impurity identification (SV). The light source can be a ring of light diodes (5) coming to a focus (2) of less than 3 mm in size. Alternatively a laser can be used.