Design and Fabrication of a PID-Controlled PET to Filament Extrusion System

Introduction

With the increasing demand for sustainable manufacturing, recycling plastic waste into useful products has become a global priority. This project focuses on developing a low-cost and efficient machine that converts discarded PET bottles into usable filament for 3D printers. The system integrates mechanical extrusion with precise thermal control, making it both eco-friendly and practical for rapid prototyping applications.

Project Objectives

To design and fabricate a machine capable of recycling PET bottles into continuous 3D printer filament.
To implement a 2-stage gear reduction mechanism for stable and controlled filament extrusion.
To integrate a PID-based temperature controller for maintaining consistent nozzle temperature.
To promote sustainable engineering practices by reducing plastic waste.
To produce high-quality filament compatible with standard FDM 3D printers.

Methodology

Shredding & Feeding: PET bottles are cut and fed into the extrusion system.
Heating & Extrusion: Material is melted and pushed through a precision nozzle.
Gear Reduction Drive: A two-stage gear reduction provides steady pulling force for uniform filament thickness.
Temperature Control: A PID controller ensures accurate and stable heating to prevent filament defects.
Spooling: Final filament is collected and wound for easy use in 3D printers.

Outcome / Results

Successfully developed a working prototype of the PET-to-filament recycling machine.
Achieved stable extrusion with uniform filament diameter.
Demonstrated the feasibility of sustainable filament production from plastic waste.
Provided a cost-effective solution for makers, researchers, and small-scale manufacturers.