Material and manufacturing process selection for 3D-printed and compression-molded fiber-reinforced composites using multi-criteria decision-making

Purpose This study aims to identify the material-process combinations for structural application. Additive manufacturing (AM) offers design flexibility for complex, near-net-shape parts, with minimal waste, precise fiber control, and reduced production time and cost for low-volume production. In contrast, compression molding (CM) is a well-established process for high-volume production of thermoplastic composites. The growing demand for customized composites leads to the selection of an optimal material–process combination. Design/methodology/approach The study uses the three-way decision-making (3WDM) approach to identify an optimal material-process combination for structural applications. Six alternatives, three manufactured using AM and three using CM, are ranked based on six experimentally evaluated criteria: tensile strength and modulus, elongation at break, flexural strength and modulus, and cost. A comparative and sensitivity analysis has been conducted for the 3WDM approach. Findings The experimental result shows that tensile modulus is highest for the 3D-printed continuous carbon fiber-reinforced nylon matrix composite marked as alternative three, A3 (13.60 GPa), while the compression-molded counterpart marked as alternative six, A6, achieves the highest tensile strength (171.75 MPa). The highest flexural modulus and strength values are also observed for A3 (6.69 GPa and 100.00 MPa). The 3WDM ranking results indicate that A3 achieves the highest ranking, followed by A6. Compared with other multi-criteria decision-making techniques, the 3WDM ranking is similar. The sensitivity results also show that A3 is the best alternative in almost all trials, regardless of the criteria's weights. Originality/value This research presents a unique application of the 3WDM approach for material–process selection between 3D printing and CM processes in the context of fiber-reinforced composites.