Polymer Thick Film Nip Width Sensor

This paper presents a novel, nip width measurement sensor. The sensor is made using polymer thick film (PTF), screen printable inks. The principle of operation is based on the shunting of a segment of a planar resistor, the segment´s length being equal to the length of the nip width. An analytical model of the sensor´s output has been developed. The model was found to be in agreement with the experimental results. Further, the sensor construction is outlined. Various sensor properties such as cross sensitivity to contact pressure, sensor evenness and repeatability are experimentally quantified. It is found that the sensor´s resolution is at least 0.25 mm. Also, a complete nip width measurement system that uses the present sensor is proposed. The application and benefits of the new sensor in measuring nip widths between rollers is discussed