NIT Rourkela patents lab-tested recycled filament extruder

A spool of filament is where many desktop 3D-printing projects quietly succeed or fail. At the National Institute of Technology Rourkela in India, a five-member team has now patented a portable extruder designed to turn recycled plastic waste into composite filament, with an estimated build cost of roughly 45,000 rupees—about $470.

The target is not an industrial feedstock plant. Associate professor Sandhyarani Biswas and professor Sujit Sen led researchers from the institute’s mechanical and chemical engineering departments toward a machine for labs, schools and small manufacturers. Those users often need reliable material but cannot justify industrial infrastructure, while improvised recycling setups can depend on manual sorting and inconsistent processing.

The system controls the point at which molten plastic cools and becomes filament. PID temperature controllers regulate the process, while reinforcement materials are blended with recycled plastic particles to form a composite. The researchers say that combination produces filament with better strength and durability than recycled filament made without reinforcement.

In laboratory testing, the resulting material showed satisfactory mechanical properties and the dimensional accuracy needed for reliable printing. That addresses a familiar weakness in FDM—the layer-by-layer process used by most desktop 3D printers—where uneven filament can leave weak spots, rough surfaces and dimensional drift. The institute says the extruder can process multiple plastic types, although it does not report a commercial production run or independent test.

Concretely, the machine could give a school, research lab or small workshop a lower-cost route to producing its own printing material from plastic waste, rather than buying commercially produced virgin-plastic filament. The immediate result is a lab-tested system, not a deployed recycling network: the patent establishes the design, while scaling, repeatability outside the laboratory and real-world adoption remain unreported.