A high sensitivity micro-pressure sensor based on 3D printing and screen-printing technologies

Abstract

A 3D-printed micro-pressure sensor with high sensitivity is developed in this paper. It is a fully printed pressure sensor fabricated using a combination of digital light processing (DLP)-based printing and screen-printing technologies, with the advantages of high manufacturing efficiency and low cost. The pressure sensor consists of a sensor substrate with a circular diaphragm and a Wheatstone bridge on the surface. First, the pressure sensor was theoretically analyzed and then verified using the finite element method (FEM). During fabrication, the sensor substrate was made from a transparent high-temperature resin, which was printed by a DLP-based 3D printer. The resistors and leads of the Wheatstone bridge were made from carbon paste and silver paste, respectively, and printed by screen-printing technology. Then, the resistors were characterized to find the gauge factor and the print consistency between different resistors. Next, the experimental setup was established for the characterization of the pressure sensor. Three loops of pressurization and depressurization from 0 kPa to 2.4 kPa were applied to the pressure sensor continuously, and the output voltage was recorded. The experimental results show that the gauge factor of the carbon resistor is 17.01 ± 1.85, the sensitivity of the sensor is 4.5522 mV/kPa/5 V, the linearity error is 2.077% FS, the hysteresis error is 6.327% FS and the repeatability error is 5.708% FS. Also, it is very convenient to obtain pressure sensors with different sensitivities and measurement ranges by changing the thickness of the circular diaphragm. All these results prove that the proposed sensor provides a low cost and high sensitivity approach for micro-pressure measurement, and that 3D printing can be applied to the production of personalized sensors.