Student Projects

PLAstic

Project Manager

Samaher Nassar, Engineers for a Sustainable World

Amount Requested

$2,870

Summary

This project aims to design and implement a student-led 3D printing filament and plastic waste recycling program on campus. Our goal is to reduce plastic waste, introduce a lower-cost material for on-campus 3D printing prototypes, and provide undergraduates with hands-on engineering experience through a real-world sustainability initiative.

Northwestern offers students widespread access to 3D printing through resources such as Mudd Library’s Makerlab, Ford Makerspace, and The Garage’s Prototyping Lab. While these spaces open doors to creativity and innovation, they also generate a significant amount of plastic waste. On average, 33% of the plastic used in a single print is waste. Recycling programs for 3D printing filament exist, but these are expensive to enroll in, and Northwestern does not have one at present. Instead, the waste is sent to landfills, where it can take hundreds or even thousands of years to decompose., In just two weeks of voluntary waste collection at the Ford Makerspace, we gathered enough discarded plastic to fill two five-gallon buckets: clear evidence of the volume of material going unused.

Our project presents both a practical solution to this problem and an educational opportunity. We will begin by focusing on PLA, one of the most common and recyclable 3D printing plastics. The Ford Makerspace, through Pam Daniels, has already agreed to support waste collection, and we have access to a consistent supply of sorted material. During the fall of 2025, we will develop and test a full recycling pipeline: collecting and grinding waste plastic, experimenting with extrusion methods and ideal temperatures, and producing filament suitable for reuse. We plan to acquire a dedicated 3D printer for trial printing and quality control.

Planned Activities/Investments

Design and First Prototype: Fall 2025 - Winter 2026

1. Initial Data Collection
   • We will begin by placing more collection buckets in the Ford Makerspace to gather all PLA 3D printing scraps from users. This will supplement the waste already collected at the end of the 2024-2025 academic year. During this phase, we will conduct mechanical testing and controlled experiments to determine the malleability and solidification times of re-melted PLA at various temperatures. These measurements are essential for identifying the conditions required for successful recycled filament production.
   • We will consult with experts in plastic recycling and 3D printing, including faculty, industry professionals, and technical staff. These conversations will help us understand existing processes and the specific needs of stakeholders. We are reaching out to faculty with expertise in plastics recycling, polymer chemistry, and sustainable manufacturing to understand plastic degradation pathways and standards for recycled filament quality. The outcome will be a foundation of technical data and requirements for designing an effective system.
2. Initial Process Creation
   • Using insights from the data collection phase, we will design a system for preparing and recycling PLA into usable filament. This includes defining each stage of the process, from sorting and grinding to melting, extruding, and spooling. We will gather materials to build a functional PLA extruder and begin constructing an initial prototype. By the end of this phase, we will have a complete CAD model and the materials to begin construction. We will document the process so future students can iterate on it.
3. Prototyping
   • We will construct a physical prototype of the system. Key components include a grinding mechanism, a controlled heating system, an extrusion mechanism to form filament, and a spooling system. Each subsystem will be designed with attention to parameters like temperature control and mechanical stability.
   • We will also design an integrated system that automates the recycling process, eliminating manual transfers. The outcome will be a modular prototype capable of turning PLA waste into filament.
4. Testing
   • Once complete, we will conduct iterative testing to refine the system. The goal is to consistently produce filament with reliable dimensions and mechanical integrity. We will perform qualitative and quantitative testing—tensile strength comparisons and DSC—ending with a report comparing recycled PLA to virgin PLA. Once it passes our standards, we will 3D print trial projects. Results will be documented and shared with stakeholders.

Expansion Phase 1: Winter 2026 - Spring 2026

1. Broader Data Collection
   • We will research additional types of plastics used in 3D printing. This includes developing a sorting and collection system for non-PLA filaments and consulting experts. We will collect data such as melting points and viscosity to adapt our system.
2. System Ideation
   • We will design a multi-material recycling system. This includes processing requirements for PETG and ABS and drafting modular upgrades. Selection will be based on availability, recyclability, and safety considerations. The goal is a scalable system for multiple filament types.
3. System Prototyping
   • We will prototype the system for each new filament, testing compatibility with thermal and mechanical properties. Each result will be a functional design optimized for a specific plastic.
4. Testing and Refinement
   • We will assess each recycled filament for consistency and usability, comparing it to its virgin counterparts. The final deliverable will be validated recycling processes.

Expansion Phase 2: 2026 - 2027

1. Expansion and Broader Application
   • We will explore recycling other plastic waste beyond 3D printing, such as plastic bottles and cutlery. The goal is to expand campus sustainability and engage more students in engineering solutions.

Impact

First, our project will provide Northwestern engineering students with a valuable hands-on engineering design experience. Despite the popularity of 3D printing, few filament recycling systems exist, making this project one where students will have significant freedom to exercise their creativity and understanding of the engineering design process. Moreover, our project is highly interdisciplinary. It combines rapid prototyping, additive manufacturing, automation, system design, and sustainability, bridging mechanical engineering, electrical engineering, computer engineering, computer science, industrial engineering, and design. By bringing together students from across majors, we will encourage students to develop crucial collaboration skills and to learn from each other as we reimagine plastic recycling. As Engineers for a Sustainable World is a barrier-free organization, we intend to reach out to students of all experience levels, sharing this experience with as many students as possible. We will evaluate our success by keeping club roster records and by inviting our team members to reflect on their experience at the end of each quarter through a Google Form and group discussion.

Second, our project will also impact the greater Northwestern community. As Northwestern community members use the 3D printers across campus, they will interact with our 3D printing waste disposal system and our recycled filament. This will increase the visibility of the waste generated by 3D printing and the need for effective recycling methods. Our project thus provides a crucial opportunity for Northwestern community members to consider this and other common open-loop processes and think more deeply about the intersection of sustainability and engineering. We will evaluate this impact by recording the mass of 3D printing filament recycled, the number of 3D prints made with 3D printing filament, and the number of people who print using the recycled filament.

Deliverables

This project will deliver fully functional and modular plastic recycling devices, capable of converting waste plastic into 3D printing filament, to campus. The devices will initially be located at the Ford Corner Makery, followed by Mudd Library, The Ford 3D Printing and Rapid Prototyping Lab, and The Garage through later iterations. We will also provide sample recycled 3D printing filament to each of these spaces, allowing Northwestern community members to test the filament for their prints. These devices and filament samples will be accompanied by usage instructions, educational materials regarding 3D printing recycling, and invitations to join our mission!

Sustainability

This project is expected to be ongoing, with continued development beyond the upcoming school year. Engineers for a Sustainable World has previously received funding from the McCormick Student Advisory Board, the Associated Student Government Sustainability Grant, and Engineers for a Sustainable World Global to support its other projects. Beyond the Murphy Grant, we will continue to seek funding through these and other avenues to continue our work on 3D printing filament recycling.

Budget Overview

Items marked with an asterisk (*) will also be used in the final prototype.

Unmentioned needed equipment will be created by our student team to reduce cost, promote innovation, and uphold our pledge of sustainability.

• Oven or Dehydrator*: to evaporate any moisture from the plastic waste before processing to avoid filament inconsistencies, system clogging, and equipment damage — $40
• Food grinder: low-cost initial shredder to break plastic into small bits for melting and extrusion — $20
• Metal Funnel: to safely transport the plastic bits to the heating area — $10
• Large drill bit: to compress the plastic and feed it into the system — $15
• High temp Hot glue gun x2: serves as a method for early-stage extrusion testing and performance evaluation — $60 total
• Nozzle replacement x2 (different sizes to match the printing practices on campus) — $10
• Digital circuit board thermostat: to measure and control the temperature and find the needed heating levels for our plastic waste to achieve filament consistency — $15
• High-temp heat insulation tape: for general safety and equipment preservation — $50
• Empty filament spools x5*: to store produced filament and feed it into 3D printers — $25 total
• 3D printer*: for filament prototype testing — $250
• Final product:
  • Commercial plastic grinder: is a larger grinder than the aforementioned one to decrease manual labour and ease automation, and produces more uniform plastic bits to ensure filament consistency — $350
  • Custom Extruder Assembly: to evenly heat up, feed, and extrude the plastic waste through a 3D printing nozzle for diameter compatibility, made from the following parts.
  • Motor + coupling: to rotate the screw and drive extrusion — $50
  • Band heaters ×3: one for each of three heating zones (as can be seen in the attached visuals) for homogeneity — $45
  • PID controllers + K-type thermocouples ×3: one per zone to control the band heaters — $60
  • Puller + Stepper Motor: to pull the plastic out of the nozzle and to the next step — $30
  • Filament Diameter Optical Sensor: to ensure filament diameter consistency and adjust pull force when needed — $70
  • Power supply (12V/24V) + wiring kit: to power and safely connect control electronics such as the PID controllers, thermocouples, optical sensor, stepper motor driver, and cooling fans — $60
  • Cooling System (e.g., Fan, tubing, water trough): to cool down the filament so it holds its shape and does not stick to itself — $95
  • Spooling System (e.g., Holder, guide tubes, bearings): to guide the filament and store it for later use — $35
  • PLA Sorting & Storage Bins: to collect and separate clean vs. contaminated plastic— $50
  • Prototype Enclosure & Safety (e.g., Acrylic shielding, E‑stop, ventilation fans) — $280
  • NIR Plastic Identification Sensor: to distinguish between different types of plastics (e.g., PLA, PETG, ABS) for compatibility in the recycling system — $1200

Total Budget Amount: $2,870

Faculty Adviser/Department

Neal E. Blair/Department of Civil and Environmental Engineering and Department of Earth, Environment and Planetary Sciences