Furthermore, PLA printing creates very little waste material, in contrast to the large amounts of waste  
Figure 1: Molecular structure of PLA [9]. that are usually created by subtractive or molding-based manufacturing [13]. Overall, PLA is still a useful material for additive manufacturing because it is easy to work with, lasts a long time, and works well, especially for prototypes and small-scale production [14]. The compatibility of PLA with AM technologies allows for a high degree of design flexibility, encouraging innovation and rapid development cycles across various industries [15]. In the evolving landscape of additive manufacturing, material selection is increasingly shaped by a combination of conventional and emerging criteria. While mechanical properties remain a critical consideration, growing emphasis is now placed on factors such as ease of manufacturing, environmental sustainability, and recyclability. Though PLA is characterized as and considered to be a potential candidate in the present scenario, looking to the future, polyethylene terephthalate (PET) is expected to garner more attention, particularly as ongoing research focuses on its potential for efficient chemical recycling and upcycling. These advancements highlight a broader shift toward sustainable materials in advanced manufacturing processes [16]. Biocomposites made by PLA are gaining significant attention due to their durability and sustainability. By combining natural fibers with PLA, these composites offer several advantages, including lightweight structures, cost-effectiveness, and a reduced environmental footprint. Additionally, they exhibit favorable mechanical and thermal properties, making them suitable for a wide range of applications such as food packaging, medical devices, and construction components [17]. Traditional manufacturing techniques could be effectively used to produce PLA-based composites that are not only mechanically strong but also structurally stiff. Life cycle assessments have revealed that PLA consumes approximately only one-tenth of the fossil fuel energy required to produce synthetic polymers. This significant reduction in energy consumption, combined with the material's biodegradability and performance capabilities, makes PLA a leading choice for the development of environmentally responsible and naturally degradable composites [18]. There is a dearth of review articles detailing the primary procedures for obtaining PLA infilled with metallic particles as composite filaments and their applications in FDM-based 3D printing technologies [19; 20]. Aviation, tissue engineering, sensor, battery, robotics, automotive, bioprinting, electrical conductivity, smart textiles, and biomedical industries are just a few more places where newly developed PLA composites have improved the qualities of 3D-printed objects [21]. Addition of metal particles slightly reduces the tensile strength and increases the thermal conductivity of the PLA-based biocomposites. However, reinforcement of continuous metallic fibers mitigates this issue. Meanwhile, addition of more than one metal into the PLA may result in incompatibility and diminishes the properties of the biocomposites drastically [22; 23; 24; 25; 26; 27; 28]. Common AM techniques include inkjet 3D printing, selective laser sintering, 3D printing stereolithography, and FDM. Because of its low production costs, ease of usage, and accessibility, FDM has quickly become the 3D printing method of choice for those on a tight budget. It has also been noted that, for the melting or fusion of metallic particles during layer-by-layer printing, high energy is required, which is possible only achievable with techniques such as SLS, DMD, and SLM, but these methods require more electrical energy, tailored environments and more safety considerations. Due to these constraints, utilization of FDM has been wide and common [29; 30; 31; 32; 33; 34; 35; 36; 37; 38]. This review article comprehensively discusses the extrusion of PLA-based filaments infilled with metal particles using suitable methods.