Fused Deposition Modelling (FDM) is a popular additive manufacturing (AM) technique that converts three-dimensional computer-aided design (CAD) models into complex-shaped objects using thermoplastic filaments as a raw material. Existing recyclable plastics, such as Acrylonitrile Butadiene Styrene (ABS), Polyetherimide (PEI), Polyether ether ketone (PEEK), Polylactic Acid (PLA), Polyethylene Terephthalate (PET), and Nylon, can be used to fabricate AM components as alternative for commercially available filaments, as they are a significant source of waste and widely available. This study presents a method of converting waste polymers into filaments for 3D printing. A dual-material extrusion system capable of processing both recycled PET and PLA under identical conditions was developed using a band heater, Proportional-Integral-Derivative (PID) temperature controller, motor, extruder screw and hopper, etc. The experiments were performed to produce the 3D filaments using recycled plastics (in the form of PET) and PLA pellets, and the results were compared. For recycled PET, waste plastics were collected, shredded, and passed through the hopper. The material was melted in the heating chamber at a temperature range of 150–220 °C for PET and 180–210 °C for PLA. The auger bit’s rotatory action delivered the molten material to the nozzle, where the final filament was extruded. The tensile strength of PLA specimens (44 ± 3.6 MPa) was found ~11% higher than PET (39 ± 3.2 MPa). Whereas, the percentage elongation of PET and PLA specimens were found as 4 and 5.2% respectively. This performance affirms that recycled PET, when appropriately processed, can bridge the gap between environmental responsibility and mechanical functionalit y in 3D printing applications. This model will likely help industries improve their efficiency and performance by lowering the cost of the new materials and making it more efficient for them. The produced filament can create personalized accessories, household goods, and distinctive, tailored fashion products.