Effects of annealing on mechanical properties, dimensional accuracy, and long-term stability of Fused Deposition Modelling (FDM)- printed carbon fibre reinforced polyamide parts

Fused deposition modelling (FDM) of carbon fibre reinforced polyamide (PA6-CF10) parts is subjected to challenges related to dimensional stability and mechanical properties. This study investigated the effect of annealing as a post-processing method for carbon fibre reinforced polyamide parts produced by FDM to enhance the mechanical properties while preserving dimensional accuracy immediately after processing and after 90 days of ambient storage. It provides a comprehensive evaluation of the effect of annealing on the mechanical properties, dimensional stability, and long-term behaviour of FDM-printed PA6-CF10 components under ambient storage conditions. To analyse mechanical properties and dimensional accuracy, samples were annealed at 90 °C to 180 °C for 60 min to 360 min. Optimal conditions were 180 °C for 210 min, yielding significant gains in tensile properties, especially for samples stored in ambient storage for 90 days after annealing. The tensile strength and tensile modulus after annealing increased by 7.27% and 5.15% compared to unannealed samples; samples tested 90 days after annealing have the tensile strength and tensile modulus increased by 14.53% and 13.79%. Dimensional deviation of the annealed samples compared to the 3D CAD model was less than 1% for samples tested 90 days after annealing. These results indicate that annealing improves both immediate mechanical performance and long-term stability of PA6-CF10 components while maintaining dimensional accuracy.