High speed photography techniques for twist propagation of yarns in a rotating rotor

A high-speed photography technique has been established to record the manifestation of the spinning yarns inside a rotating rotor in this paper. A high-speed CCD camera and a stroboscopic-flash have been used. The highest capturing frame rate and the highest flash rate are 1,001 frames per second and 33,000 flashes per minute, respectively. The images are directly digitized into 256256 pixels with 8 bits gray level. These digital images are continuously stored in an interleaved dynamic RAM buffer, which is connected with a computer. Some optical techniques, such as focus, have been used in this high-speed photography technique. Twist propagation properties of the spinning yarn tail inside a rotating rotor, such as their size and twist level, have been determined according to the images, which are taken at the rotary speed of the rotor around 16,000 revolutions per minute. This technique has a capacity of detecting yarn tails when the rotary speed is higher than 100,000 revolutions per minute.