Non-Destructive Technique Based on Acoustic Transducers and Digital Signal Processing to Detect Failure in the First Layer in FDM

The manufacturing of the first layer in fused deposition modeling (FDM) plays a crucial role in the fabrication of the part, as any irregularity in this early stage can lead to complete fabrication failure, or the occurrence of defects such as part detaching, and warping. Thus, sensor-based monitoring techniques aiming to optimize the process are of utmost importance. Thus, this work investigates the application of the chirp-through transmission technique (CTT) to detect failure in the first layer in FDM using two acoustic sensors. A 3D printer by GTMax3D was used in the experimental tests, which consisted in manufacturing polylactic acid (PLA) squared monolayer pieces with four distinct printing conditions. The signals were collected through a data acquisition system at 200kHz, and later processed in MATLAB. The results show good correlation between the signals and the conditions of the first layer manufactured, demonstrating viability of the technique.