Experimental characterization of the interlayer fracture toughness of FDM components

The present work is aimed at determining the inter-layer fracture toughness behavior of FDM parts. Double-cantilever beam specimens were produced and tested using already-established testing standards to capture the fracture toughness behavior. A new sample configuration was also proposed to overcome some limitations concerning sample preparation, which is also influenced by human factors. The two kinds of samples were compared to determine the suitability of the proposed solution to address the critical energy release rate in mode I crack opening. The fracture zone characteristics were investigated by ex-situ measurements using optical and scanning electron microscopy. Thermal analysis was performed during the deposition process to capture the variation and distribution of the temperature. The results indicated that the insertion of Polyimide and particularly the pause time required may alter the thermal history leading to lower polymer healing of the tested layer. This leads to an underestimation of the mechanical behavior of the tested samples. On the other hand, the proposed sample with nested spacers does not introduce artifacts in the thermal history leading to a more reliable measurement of the Interlayer Fracture Toughness.