PSI - Issue 79

Popa Cosmin Florin et al. / Procedia Structural Integrity 79 (2026) 354–360

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1. Introductions Additive Manufacturing (AM) is a process that fabricates complex components layer by layer in a fast and efficient manner, without the need for additional post-processing operations to complete the component (Zhang, 2018). This method has gained widespread application across various fields, including biomedical engineering Malik et al. (2015), Mulford et al. (2016), mechanical engineering Henriques et al. (2018), Ahmed (2013), and Kroll (2011). Additive Manufacturing (AM) encompasses various 3D printing technologies, and this paper focuses on Fused Deposition Modeling (FDM) due to its ease of use, speed, and minimal material waste. The process of creating a component using FDM involves several steps, starting with the development of a digital 3D model. This model is then imported into 3D printing software, where parameters such as print speed, bed temperature, nozzle temperature, and raster orientation are defined. Once all parameters are set, a G-code file is generated and sent to the 3D printer. The printing process involves pulling a filament through two rollers into the heated nozzle, which melts the material at the specified temperature to build the part layer by layer. In the literature, several researchers have studied the impact of raster orientation on the mechanical properties of 3D-printed specimens, Marsavina et al. (2022). Ziemian et al. (2012), Lou-Ke et al. (2024) and Joseph et al. (2020), for example, observed significant variations in tensile strength based on raster orientation. Their findings showed improved tensile properties as the raster angle increased from 30° to 90°. For shear specimens, Kamori (2023), Bovier et al. (2006), and Rauch et al. (1998) have extensively analyzed the homogeneity of the shear zone and identified in-plane simple shear with a single shear zone as an effective technique for determining shear strength and analyzing in-plane plastic anisotropy. In their study, Liu et al. (1990) highlight that any anisotropy in shear specimens can significantly influence test results. Considering that the specimens used in this paper were 3D-printed, some variations in the results were likely influenced by irregularities in the manufacturing process. Digital Image Correlation (DIC) is mainly used for deformations and shear deformations, and this technique is allowed to be measured in any type of material. The advantage of the non-contact technique is that the measurement is three-dimensional, Matus (2012). This paper aims, to evaluate the mechanical behavior of polyethylene terephthalate glycol (PETG) specimens printed at different raster angles, comparing results between contoured and un-contoured specimens. Additionally, the study compares measurements obtained using a mechanical extensometer and a Digital Image Correlation (DIC) system. The findings indicate that contoured specimens demonstrate better repeatability, with more consistent results in the tensile tests. 2. Material and methods The material used for the specimens was white PETG. The specimens were printed on Prusa MK3 with a 2 mm nozzle, and the diameter of the filament was 1.75 mm. For printed parameters, a nozzle temperature of 230°C was used, and the bed temperature was 85°C. The shear specimens’ geometry was carried out according to ASTM 831-5 specifications and the tensile specimens were carried out according to ISO 527-2. Both types of specimens were created with different raster angles, likewise specimens without contour. The angle of the specimen was 0, 45, and 90 degrees. Six specimens were manufactured for each configuration. Figure 1 presents the tensile specimens, a) printed specimens with contour, and b) the specimens sketch.

Fig. 1. Tensile Specimens a) with contour and without contour, b) specimen drawing