A Self-Energized Sensor for Wireless Injection Mold Cavity Pressure Measurement: Design and Evaluation

Abstract

This paper presents the modeling, design, and experimental validation of a self-energized sensor system for pressure measurement in the injection mold cavity using ultrasound as the information carrier. The sensor extracts energy from the polymer melt pressure and discretizes the pressure information into ultrasonic pulses for wireless transmission through the mold to a remote receiver. Analytical and numerical models are presented for three constituent components of the sensor: the energy converter, the threshold modulator, and the signal transmitter. Quantitative results were obtained to guide the parametric design of each constituent component. Simulations and experimental studies have validated the functionality of each individual component, as well as the sensor as an integrated unit. In addition to the injection mold pressure measurement, the sensing technique developed is applicable in a broad range of process monitoring applications where high pressure fluctuations occur.