Acoustic Wave-Based Data Transmission for Multivariate Sensing

Improving process observability is of high relevancy to improved manufacturing process control. This paper describes a novel measurement technique using acoustic waves for the transmission of multiple physical parameters from within the cavity of an injection mold to a receiver outside: temperature, pressure, velocity, and viscosity of polymer melt. Such a technique is a key to improved monitoring and control of plastic injection molding. A coded-acoustic wave modulation scheme enables multiparameter transmission through an acoustic transmitter with variable gains. This enables selective resonant frequencies that provide the carriers for the individual parameters to be transmitted, while suppressing noise induced in the modulation process. The presented acoustic wireless sensing method is applicable to a wide range of process monitoring scenarios.