Automatic yarn characterization system

This paper presents an innovative, low cost, portable and high-precision yarn evaluation tester, YSQ (Yarn System Quality), for quality control of yarn characteristics under laboratory conditions. It presents a modular format, which can integrate simultaneously yarn hairiness, mass, regularity and diameter measurements. The quantification of yarn hairiness and diameter variation (with a sampling resolution length of 1 mm) is carried out using photodiodes; the diameter characterization, based on 0.5 mm width samples, employs a linear photodiode array; the measurements of mass variation, based on samples of 1 mm, employs a parallel plates capacitive sensor. In the YSQ measurement parameters based on optical sensors, a coherent signal processing technique with Fourier analysis is used, to obtain linear and consistent output signal variations. A comparison between results obtained using the YSQ and a commercially available solution is presented.