Fiber Bragg grating monitoring during 3D wire arc additive manufacturing process

Fiber Bragg grating can be used to monitor temperature, strain, …, in harsh environments. Benefiting from this process, high temperature type III fiber Bragg grating were inscribed in Telecom optical fiber in order to monitor the manufacturing of stainless steel (316L) walls using the wire arc additive manufacturing process. In this study, walls of about 9 cm long per 2 cm width and 10 cm height was built. The gratings were placed inside steel capillaries ranging from 1 mm to 5 mm of external diameters, so as to protect the fiber from the molten metal and to keep the fiber free from any stress. This enables the measurements of only the required temperature fields. Some fibers were also fixed on the substrate to measure its deformation. During the process, temperatures up to more than 200°C were measured, for a grating located at less than 1 cm from the wall edge and deformation up to 1.2 mε at room temperature. These measurements provide new information to optimize the manufacturing of parts using wire arc additive manufacturing process.