PSI - Issue 83

Manuel A.R.V. Esteves et al. / Procedia Structural Integrity 83 (2026) 146–153

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recycled PLA printed at three different nozzle temperatures (220, 237, and 255 °C), while maintaining all other parameters constant. Impact tests were conducted at both room and low temperatures to assess the combined effects of recycling and service conditions on energy absorption capacity. 2. Experimental details 2.1. AM material PLA was selected as the base material for this investigation, given its widespread use in FDM and its relevance to sustainability-oriented manufacturing. To evaluate the feasibility of employing recycled PLA in FDM applications, two distinct filament sources were considered. The first consisted of a commercial virgin PLA filament supplied by the 3D printer manufacturer, which was used as the reference material. The second comprised a fully recycled PLA filament obtained from a supplier specialized in the recovery and reprocessing of polymer waste into printable filaments. Both materials were supplied with a nominal filament diameter of 1.75 mm. According to the technical documentation provided by the virgin PLA manufacturer, optimal mechanical performance is achieved when specimens are printed with their principal axis aligned in the x-y plane and tested in the same orientation. This recommendation applies to both flexural and impact loading conditions. The corresponding mechanical properties are reported in Table 1, resulting from the application of standards ISO 178, ISO 179, and ISO 527 (BAMBU 2025). The manufacturer indicates that these properties were obtained using a nozzle temperature of 220 °C, a build-plate temperature of 35 °C, a printing speed of 200 mm/s, and a solid infill configuration (100%).

Table 1. Pristine PLA properties.

Property E (x-y)

Average ± deviation 2580±220 MPa 2060±170 MPa

E (z)

Tensile strength (x-y) Tensile strength (z)

35±4 MPa 31±3 MPa 12.2±1.8 % 7.5±1.3 %

Breaking elongation rate (x-y) Breaking elongation rate (z)

Ef (x-y)

2750±160 MPa 2370±150 MPa

Bending modulus (z) Bending strength (x-y) Bending strength (Z) Impact strength (x-y) Impact strength (z)

76±5 MPa 59±6 MPa

26.6±2.8 kJ/m² 7.9±1.2 kJ/m² (notched)

13.8±0.9 kJ/m²

The recycled PLA filament used in this study was produced entirely from reclaimed material. The mechanical properties declared by the supplier are summarized in Table 2, following standards ISO 527 and ISO 179-1eA (SAKATA3D 2025). Unlike the virgin PLA, detailed information regarding the printing parameters employed to obtain the reported properties is not provided. The only processing condition explicitly specified by the manufacturer is the use of a 100% infill rate during specimen fabrication.

Table 2. Recycled PLA properties.

Property

Average 3,500 MPa 45 MPa

E

Tensile strength Tensile elongation Charpy notched impact

5%

118 J/m

2.2. Charpy specimen characterization

The test specimens for this study were designed in accordance with the relevant ISO standards for characterization of polymeric materials. Thus, the impact specimens were produced according to ISO 179-1 for Charpy testing. The geometry and nominal dimensions are presented in Fig. 1.