Ultrasonic Testing of Short-fiber Reinforced Reproduction Filaments for 3D Printers

Abstract

In this study, ultrasonic testing equipment is developed to evaluate 3D-printer filaments, particularly short-fiber reinforced reproduction filaments. Recently, 3D printers based on fused deposition modeling (FDM) using thermoplastics have become popular because of the simplicity and relatively low cost. In addition, filaments containing carbon or glass fibers have also been developed to improve the mechanical properties of products. In 3D printers using reproduced filaments, the quality of the filament affects the reliability of the products, particularly in the case of fiber-reinforced filaments. In the equipment developed for this study, ultrasonic waves that passed through the target filament along the longitudinal direction were measured, and the physical properties of the filament were predicted based on wave propagation velocity. To improve the accuracy of the velocity measurement, the Akaike information criterion (AIC) was introduced to detect the wave arrival time of signals. In addition, a finite difference time domain simulation was conducted to confirm the validity of the ultrasonic inspection. It was determined that change in velocity in ultrasonic waves can be used as an index of filament degradation.