Energy consumption, process stability, and tensile anisotropy of FFF-printed PLA and carbon fiber-reinforced PLA: Effects of build orientation and chamber conditions

This study experimentally investigated the effects of build orientation and chamber conditions on the energy consumption, mechanical performance, and process stability of polylactic acid (PLA) and carbon fiber-reinforced PLA (PLA-CF) manufactured using Fused Filament Fabrication (FFF). Flat, on-edge, and Z build orientations were examined while maintaining constant processing parameters. Energy consumption was evaluated separately for the heating, printing, and cooling phases. The results showed that build orientation had a greater influence on energy consumption than material type. The printing phase was the dominant contributor to total energy consumption, whereas the heating and cooling phases exhibited relatively limited variation. Z-oriented specimens required substantially higher energy consumption than flat and on-edge specimens. Mechanical testing revealed pronounced anisotropy, with the highest tensile strength obtained in the on-edge orientation for both materials. In the on-edge orientation, PLA-CF exhibited approximately 26% higher tensile strength than neat PLA. In contrast, Z-oriented specimens showed significantly reduced mechanical performance. Under the investigated Z-oriented printing conditions, chamber configuration influenced both energy consumption and process stability. Prolonged PLA printing under closed-chamber conditions led to extruder clogging, whereas no comparable printing instability was observed for PLA-CF. Overall, the results demonstrated that build orientation was the dominant factor affecting both energy consumption and mechanical performance, while chamber conditions became important for process stability during prolonged Z-oriented printing.