An Initial Study Towards In-SITU Ultrasonic Monitoring and Measurement of Part Properties during Photopolymer Based Additive Manufacturing

摘要

This paper presents our recent preliminary study on using a novel in-house ultrasonic measurement technique to investigate ex situ the elastic modulus evolution during a photopolymer based additive manufacturing (PAM). Experiment is designed to study the effects of PAM process parameters on the elastic modulus of fabricated samples. A unique lab-built line-focused ultrasonic transducer based on time-resolved defocusing is employed to measure velocities of the surface waves (Rayleigh waves and longitudinal bulk waves) leaking from the samples. The samples' elastic properties can be calculated from the obtained wave velocities. As a result, changes in elastic modulus with the varying PAM process conditions are successfully detected and quantified by this ex situ ultrasonic technique, revealing important information on both the "need-to" and "how-to" develop an in-situ monitoring and measurement system for part properties during PAM processes. The research outcome will not only enhance understanding about evolution of mechanical properties during PAM, but also offer insightful guidance on a future development based on the reported ex-situ ultrasonic technology towards an in-situ ultrasonic system for in-process measurement and advanced control of PAM.