Monitoring the strain and stress in FDM printed lamellae by using Fiber Bragg Grating sensors

Abstract

Fused deposition modeling (FDM) is an additive manufacturing technology that is used for prototyping and production applications through a computer-aided manufacturing process. In process, a high thermal gradient can lead to harmful residual stresses, resulting in unexpected deformation or delamination failure. To improve the quality of 3D printed parts, it is important to characterize the residual stress during FDM 3D printing. Here, we develop a stress inversion model and present an in-situ measurement technique to obtain the substrate strain using Fiber Bragg Grating sensors. Combining the theoretical model and the in-situ strain measurements, the residual stress of printed lamellae is determined. To evaluate the technique, circular lamellae were printed with different printing parameters, including layer thickness, layer number, and printing direction, the evolution law of substrate strain during the printing process and the influence of the printing parameters on the residual stress were analyzed.