During metallic wire drawing processes, the presence of knots and the failure to detect
them can lead to long production interruptions, significant economic losses and a lower
quality of final product. Consequently, there is a pressing need to develop methods
for real-time detection and prevention of this fault. In this paper, a sensor to prevent the
formation of knots during the metallic wire drawing process is presented and evaluated
by means of experimental data. This fast, inexpensive, non-contact sensor is based
on electromagnetic principles such as eddy current induction, magnetic reluctance
variations and magnetic coupling. The proposed sensor without direct contact can detect
knots in a target metallic wire by measuring the impedance variations of a calibrated
sensing coil caused by either a knot or an unwound loop rising from a wire rod. The
incorporation of this type of sensor into a wire-drawing machine can avoid the
tightening of the knot, thereby reducing downtime and increasing the security and
reliability of the process. Experiments were conducted using a scale model of the above
proposed system. This allowed highlighting the sensor’s potential by carrying out an
automatic, real-time knot detection during steel wire drawing
