In situ monitoring of polymer 3D printing using ultrasonic Lamb waves generated by a 3D printed wedge

Abstract

The additive manufacturing (AM) of polymers has become increasingly popular in industry to create complex geometries for parts while maintaining low manufacturing costs. Rapid nonuniform cooling introduced during the printing process can lead to part warping and delamination which are precursors to part failure and/or poor part quality. Previous researchers have integrated online monitoring techniques such as optical or thermal sensors. These techniques are limited to monitoring exposed areas of the part leaving unexposed areas unmonitored. In this work, ultrasound has been implemented to monitor the inaccessible areas where defects can originate. An in situ guided wave-based ultrasonic inspection system was implemented into the test setup to detect delamination during printing. A 3D printed ultrasonic wedge was designed to generate S0 guided waves that were received by a broadband pinducer. The wedge was printed onto a plate of 6061 aluminum acted as the print bed for the experiments. A 3D printed part was printed between the transducers, which was continuously monitored for signs of delamination. This presentation will report on precursors to part delamination that are difficult or impossible to sense using previous methods. This work seeks to reduce 3D part failures and, thus, polymer waste associated with 3D printing.