Optimizing fused filament fabrication parameters for PETG + 20% CF oven door brackets as a sustainable alternative to injection molded PA6 + 30% GF

Abstract

This study investigates the application of fused filament fabrication (FFF) for producing oven door brackets from polyethylene terephthalate glycol (PETG) reinforced with 20% carbon fiber (PETG + 20% CF), positioning it as a sustainable alternative to injection-molded polyamide 6 reinforced with 30% glass fiber (PA6 + 30% GF). A Taguchi L9 orthogonal array was employed to optimize three critical FFF parameters: nozzle temperature, layer height, and infill pattern. Mechanical characterization (tensile, flexural, and impact tests) and thermal analyses (heat deflection temperature, Vicat softening point, differential scanning calorimetry, and thermogravimetric analysis) were conducted in accordance with ISO standards. Optimized PETG + 20% CF specimens achieved tensile and flexural strengths of 48.65 and 69.3 MPa, respectively, compared to 171.9 and 206.22 MPa for PA6 + 30% GF. Thermal evaluation indicated a heat deflection temperature of 74.29 °C and a Vicat softening point of 82.63 °C for PETG + 20% CF, which remain sufficient for safe service under typical oven operating conditions (∼56 °C). Results further demonstrate the influence of FFF parameters on the mechanical performance of PETG + 20% CF, with the optimal condition identified as 280 °C nozzle temperature, 0.15 mm layer height, and triangular infill pattern. Although PA6 + 30% GF maintains superior absolute properties, the findings highlight the potential of PETG + 20% CF as a recyclable, design flexible material suitable for functional home appliance components, while also providing insights into parameter–property relationships that guide future optimization strategies.