Defect Imaging in Additive Manufacturing Process of Metals through Laser Ultrasonic Technique

Abstract

Additive manufacturing (AM) has become commonplace because it can create products with complex shape without expensive mold. However, since various defects are sometimes introduced during the manufacturing process, defect inspection is essential for assuring the strength of the AM parts. Because the previous research has shown defect imaging technique executed after AM processes, this study aims to develop an experimental system of defect imaging during manufacturing process. Using diffuse field of ultrasonic waves, the defect imaging was realized from the ultrasonic waves detected under the build plate, not on the specimen. Following the results, we developed a new experimental system to conduct both manufacturing and inspection at the same time. In this experimental system, receiving transducers are installed under the plate on which manufacturing process is conducted so that they cannot prevent manufacturing process from being done. We expect that monitoring of additive manufacturing process is feasible with the experimental system.