This work presents a single-nozzle/bi-extrusion FDM technology featuring two material inputs and heating sections connected with a mixing device with a reinforced mixing mechanism. The device ensures uniform mixing of materials, consistent print quality, and functionality, while an air-cooling system allows printing with materials having different solidification temperatures. Trials with six Dryflex TPEs demonstrated precise regulation of material flows, enabling dynamic adjustment of material blends and creation of multiple functionalities in one product. The technology also creates functionally graded materials (FGMs) in transition zones, improving interlayer adhesion and mechanical performance. This advancement enhances production flexibility, efficiency, and product quality, and expands material availability for additive manufacturing.