An evaluation of materials and processes employed in the construction of novel thick film force sensors

Abstract

Novel thick film strain gauges have been constructed using a z‐axis orientation on insulated stainless steel for a variety of force sensing applications. These devices exhibit high gauge factor and good thermal stability compared with conventional x‐axis devices and offer other mechanical advantages due to their mode of operation. The work reported here investigates the characteristics of different types of stainless steel substrate and different types of insulating material used in the construction of the sensors. Both ferritic and austenitic steels have been investigated, together with different resistive and insulative compositions. The temperature coefficient of resistance of the devices has been shown to be a complex function of device thickness, surface area and the difference between the thermal coefficients of expansion of the various materials employed.

An explanation of thermal behaviour of thick film strain gauges

“…This consideration is confirmed by some earlier work [14], which shows that the resistors printed on different dielectric materials exhibit a noticeable difference in their temperature characteristics although the substrate materials are the same. This is possibly due to the different chemical interactions between resistor and dielectric, i.e.…”

LTCC Post Load Cell

“…A design of a z-axis piezoresistive force sensor, using the geometry shown in Figure 1b, was previously introduced to obtain high levels of strain [11,12].…”