Fused Filament Fabrication (FFF) is a widely embraced material extrusion (MEX) additive manufacturing (AM) process to produce complex three-dimensional structures, and it is typically used in the fabrication of biodegradable polymers for biomedical applications. However, FFF as a fabrication process for blended polymeric materials needs to be optimized for enhanced mechanical properties. In this work, biodegradable polylactic acid (PLA)/polyhydroxyalkanoate (PHA) dog-bone and notched specimens are printed to determine optimum printing parameters for superior mechanical properties in FFF additive manufacturing. The effect of layer thickness, infill density, and printing bed temperature on mechanical properties is investigated by employing a design of experiments (DoE) approach using response surface methodology (RSM). Experimental results showed the significance of the opted parameters for mechanical properties of the PLA/PHA blend. Then, optimum values for layer thickness, infill density, and printing bed temperature are identified for tensile and impact strength and an empirical relationship between parameters is formulated for low density and cost-effective fabrication. Finally, the analysis of variance (ANOVA) is performed to check the adequacy of the model for the influence of process parameters and their mutual interactions. The verification experiments validated the adequacy of the proposed model for PLA/PHA blend in FFF additive manufacturing.

Since the late 1980s, additive manufacturing (AM) has emerged as a prominent fabrication technology, experiencing significant advancements over the past decades. Even with its rapid development, this technology still faces many manufacturing challenges. Driven by the development of AM, 5D printing evolved from conventional 3D printing by incorporating five controlled degrees of freedom (three translational and two rotational axes) to enable non-planar deposition, curved-layer fabrication, and improved control of deposition orientation. This review critically analyses and summarizes 5D printing technology, detailing its development, material innovations, applications, and future outlook. The study starts with the evolution of printing from 1D printing, through 2D printing, to 3D printing, detailing its limitations and the paradigm shift to 5D printing. Further insights are also discussed regarding material selection, which plays a crucial role in determining the functionality and performance of 5D printing. Moreover, various applications of 5D printing across the aerospace, automotive, biomedical, jewelry, and food industries have been discussed, highlighting its potential for lightweight, high-strength, and tailored components. Furthermore, a detailed SWOT analysis of 5D printing has been presented to evaluate the strength, weaknesses, opportunities and threats of the technology, providing a strategic perspective of 5D printing in the industry. Lastly, future prospects for multi-material integration, AI-optimized printing and hybrid manufacturing methods are discussed.