Different behavior of RMF signals was shown in specimens with different printing directions. RMF gradients show more distinct features in the defect area, making it possible to capture defect information. Characteristic parameters were defined to characterize the degree and range of distortion in the RMF gradients curve. The results show that the characteristic parameters are related to the crack width, which further proves the capability of MMM technology in defect evaluation. This research provides a highly sensitive and non-contact method for evaluating the quality and safety of WAAM parts.

With the advancement of modern industrial technology, additive manufacturing (AM), has become pivotal in manufacturing due to its layer-by-layer material deposition approach, contrasting with traditional subtractive methods [1]. Wire and arc additive manufacturing (WAAM), a key AM branch, stands out for its high energy density and melting efficiency, enabling rapid metal forming and making it an ideal choice for large structural parts. Its advantages in material utilization and cost-effectiveness drive broad applications in aerospace, shipbuilding, and energy sectors.

However, there are also some challenges and issues in the process of WAAM. As the metal wire is melted and deposited layer by layer under the action of the arc, complex thermal cycling and heat accumulation are involved in the process, which may lead to problems such as coarse grains and anisotropic properties in the deposited layer. Changes in process parameters during the manufacturing process, such as voltage, deposition speed, wire feed rate, travel speed and preheat temperature, can result in various defects in the deposited layer of the additive manufactured product, including quality defects (e.g., porosity, cracks, lack of fusion, and slag inclusion)) and profile defects (e.g., unacceptable distortion, delamination, and geometrical deviations).

Read the full article at Science Direct.