NiCr Thin Film Strain Gauges Fabricated on Glass Substrates

Abstract

In order to investigate the strain gauge characteristics of NiCr thin films, 500 nm NiCr (80 wt.-% and 20 wt.-%, respectively) thin films were deposited on glass substrates by DC magnetron sputtering. After deposition, NiCr thin films were characterized by using X-Ray diffraction analysis, scanning electron microscope and four-point probe techniques inview of crystallization, phases, film structure and electrical resistivity. After characterization, NiCr thin films were shaped into strain gauges by photo lithography and wet etching techniques. Strain gauges were tested with different loads, and strain values were calculated by comparing the results with commercial NiCr strain gauges with the same surface area. Resistivity change vs. strain was plotted, and the gauge factor of fabricated thin film strain gauges was evaluated as 1.23.

Structure design and optimization for a cutting force measurement tool with embedded nickel–chromium film sensor

“…where a is the distance from any point of the tool shank cross section to the strain/stress neutral layer and A is the cross-sectional area of tool shank. With equations (2) and (3), equation (1) becomes…”

“…The value of k, which is taken as 2.0, here, depends on multiple factors including the Ni-Cr resistance grid thickness. 1,4 The substrate strain at center in the Y-axis direction is taken as the sensor resistance grid strain e. Figure 6 shows the simulated output voltage versus force in Z-axis direction for the two models. As can be seen from Figure 6, the value of output voltage is proportional to the external force in both models.…”

“…The output characteristics of the sensor are gauged with the relationship between the strain of sensor and the external force of the tool. If the k and e are known, the sensor output voltage can be obtained with formula (1). The value of k, which is taken as 2.0, here, depends on multiple factors including the Ni-Cr resistance grid thickness.…”

“…The value of k, which is taken as 2.0, here, depends on multiple factors including the Ni-Cr resistance grid thickness. 1,4 The substrate strain at center in the Y-axis direction is taken as the sensor resistance grid strain e.…”

“…The chemical composition and physical properties of the thin film strain resistance grid were studied, which gave a strain resistance grid factor value of 1.23. 1 C Taylor and SK Sitaraman 2 installed the Ni-Cr alloy thin sensor close to packaging solder bumps to measure the stress in packaging process. M Sohgawa et al 3 fabricated a tactile sensor consisting of micro-cantilevers and Ni-Cr thin film strain resistance grid on the silicon substrate to detect the shear force in the sliding process.…”