Fabrication, Performance, Characterization and Experimental Calibration of Embedded Thin-Film Sensor for Tool Cutting Force Measurement

Abstract

Thin-film strain sensors are widely used because of their small volume, fast strain response and high measurement accuracy. Among them, the thin-film material and preparation process of thin-film strain sensors for force measurement are important aspects. In this paper, the preparation process parameters of the transition layer, insulating layer and Ni-Cr alloy layer in a thin-film strain sensor are analyzed and optimized, and the influence of each process parameter on the properties of the thin film are discussed. The surface microstructure of the insulating layer with Al2O3 or Si3N4 transition layers and the film without transition layer were observed by atomic force microscopy. It is analyzed that adding a transition layer between the stainless steel substrate and insulation layer can improve the adhesion and flatness of the insulation layer. The effects of process parameters on elastic modulus, nanohardness and strain sensitivity coefficient of the Ni-Cr resistance layer are discussed, and electrical parameters such as the resistance strain coefficient are analyzed and characterized. The static calibration of the thin-film strain sensor is carried out, and the relationship between the strain value and the output voltage is obtained. The results show that the thin-film strain sensor can obtain the strain generated by the cutting tool and transform it into an electrical signal with good linearity through the bridge, accurately measuring the cutting force.

Study of the Pattern Preparation and Performance of the Resistance Grid of Thin-Film Strain Sensors

“…The experimentally prepared alloy film strain sensor is mainly used for tensile experimental research, and the shape of the substrate is the same. First, a surface treatment was performed on a stainless-steel substrate with a thickness of 0.55 mm, and the preparation of the insulating layer was completed by sputtering a thickness of 600 nm of Al 2 O 3 and a thickness of 300 nm of Si 3 N 4 onto the surface [24]. Figure 1 shows the film patterning process of PMS.…”

Design and Optimization of Tool-Embedded Thin-Film Strain Sensor Substrate Structure

“…Likewise, the thin-film strain sensor is embedded with the tool [ 10 , 11 ] to measure the cutting force. As shown in Figure 1 b, the thin-film strain sensor [ 12 , 13 ] is composed of the film resistance grid and the elastic substrate, and the elastic substrate is the carrier of the film resistance grid. The tool is subjected to a cutting force, and the deformation of the sensor substrate makes the resistance of the film resistance grid change, causing the output of the measurement circuit to change.…”