Experimental and numerical investigation of FFF-printed carbon fiber–reinforced PETG for functional polymer composite components

Fiber-reinforced polymer composites are increasingly used in home appliance components due to their strength-to-weight ratio and thermal resistance. Injection-molded polyamide 6 reinforced with 30% glass fiber (PA6 + 30%GF) is employed for inner oven glass supports in easy disassembly oven door systems, enabling removal of inner glass panels for cleaning. However, the demand for reduced tooling cost, rapid customization, and sustainable manufacturing has increased interest in additive manufacturing alternatives. This study presents an experimental and numerical investigation of fused filament fabrication (FFF)-printed polyethylene terephthalate glycol reinforced with 20% carbon fiber (PETG+20%CF) as an alternative to injection-molded PA6 + 30%GF. Experimental evaluation included flammability and heat-resistance testing using Glow-Wire, Needle-Flame, and Ball Pressure tests according to the IEC 60695 series, in addition to a full-scale heating test conducted in a freestanding gas cooker following EN 30-1-1 requirements. Temperature measurements confirmed that the maximum steady-state temperature at the PETG+20%CF support location remained below 73 °C during normal operation, which is lower than the measured glass transition temperature of PETG+20%CF (∼80 °C), thereby confirming thermal suitability under service conditions, with limited permanent deformation observed. Finite element analysis was conducted at room temperature (23 °C) and elevated temperature (80 °C). Simulation results showed increased deformation for PETG+20%CF at elevated temperature, while PA6 + 30%GF maintained stiffness and dimensional stability. Numerical predictions showed good quantitative agreement with experimental measurements.