Investigation of Toy Parts Produced Using Injection Molding and FDM and Selection of the Best Manufacturing Method: A Multi-Criteria Approach

Three-dimensional (3D) printing has become a promising alternative to conventional methods in plastic part production, particularly for customized or low-volume applications such as toys. This study compares toy components produced by Fused Deposition Modeling (FDM) using polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) filaments and those produced by traditional injection molding using ABS pellets. Unlike in many previous studies based on standardized test samples, a real toy part was evaluated in terms of compressive strength, dimensional accuracy, surface quality, and cost. Experimental results revealed that ABS parts produced by injection molding exhibited the highest compressive strength (3.93 kN), followed by PLA-FDM (2.97 kN) and ABS-FDM (0.95 kN). Similarly, injection-molded parts showed superior surface smoothness and dimensional accuracy. Cost analysis indicated that injection molding is economically viable only when production exceeds 735 pieces, while FDM becomes more attractive for smaller batches due to its low initial cost. A multi-criteria decision-making analysis using the TOPSIS method was conducted to integrate technical and economic factors. Results showed that injection molding is preferable for mass production, whereas PLA-FDM is more suitable for low-quantity, cost-sensitive scenarios.