A Compact Photoacoustic Sensing System for Expeditive Estimation of Paint’s Viscosity

Non-invasive and rapid measurement of paint's viscosity is a challenge for most of the paint manufacturing industries. This study proposes a novel photoacoustic (PA) sensing technique for the measurement of paint's viscosity. The continuous wave laser diode used in an excitation makes the overall system compact and portable. The application of the sweep frequency acoustic interferometry principle enhances the signal to noise ratio of the PA signal. The paint samples are mixed with a thinner solution to vary their viscosity. Zahn-4 cup is used to measure the viscosity of the paint samples which acts as the ground truth. A regression-based analysis is performed to estimate the viscosity through PA measurements. Viscosity measured through PA is compared with the ground truth and the error found is approximately less than 5%. The simple computational method and instrumentation used in this technique enable it to be deployed in industries for rapid estimation of the viscosity of paints.