Capstone Design (with ARL-MLS Lab @ University of Toronto)

This project is being conducted in collaboration with the Advanced Research Laboratory for Multifunctional Lightweight Structures (ARL-MLS) at the University of Toronto, supervised by Prof. Kamran Behdinan

(link to the lab: https://arlmls.mie.utoronto.ca/)

(download the complete design report here)

This project ranked FIRST out of more than 80 entries in the 2024-2025 University of Toronto Mechanical Engineering Capstone Showcase, AWARDED $1000.

Objectives

Aims to design a temperature control unit for the Anisoprint A3 CFC (Continuous Fiber Co-extrusion) 3D printer, to mitigate the problem of non-uniform cooling between adjacent printed layer that cause edge warpage and ​delamination. 

Design Outcome

A single-packaged, user-friendly control unit has been designed and prototyped.

The design is capable of heating a nearly half-cubic-meter printer chamber from room temperature to any target between 40°C and 65°C, with error within ±0.5°C, oscillations under 0.5°C, and a temperature uniformity of ±2°C across the entire chamber.

The Design in the Printer

Design Showcase Video

The system uses forced convection to heat the chamber. 

Unheated air is drawn in by a centrifugal fan at the top, forced through an enclosed air duct across a high‑power PTC heater at the bottom, and then introduced into the printer enclosure via a specially designed deflector at the outlet. 

Users can adjust the target temperature by a remote. Both the current and set temperatures are displayed on the LCD screen.

The design uses a special-designed correlation sensor and a PD controller to regulate the temperature.

Working Principles

Airflow Direction

Air Spreading Direction

Isometric Diagrams

Explosive Diagram of the Design

Product isometric diagram

Product isometric diagram (transparent)

Performance

The design delivers a high-accuracy, high-uniformity, and high-stability control outcome.

*StDev stands for standard deviation of temperature throughout the chamber

Design Prototype

Product Package

Prototype Product Photo (left: front; right: back)

A fully developed prototype was fabricated with an enclosure 3D‑printed from PA6‑CF, housing a 47 CFM centrifugal fan and an 800 W PTC heater. For more details, please refer to the video. 

My task includes:

As the team leader, I was responsible for:

Mechanical & Electrical Design & Prototyping
         • Produced the complete CAD model, including internal compartments, mounting holes, and airflow ducts.
         • Designed the schematic, laid out the PCB, and carried out board soldering.
         • Prototyped and assemble the design.

Air‑Flow Optimization
         • Ran a full‑factorial Design of Experiments (DOE) to optimize the deflector geometry and duct length.
         • Improved in‑chamber temperature uniformity by 62.9%, achieved in-chamber uniformity of 2°C.

Adaptive PD Temperature Control
         • Developed a PD controller whose proportional gain adapts to the target set‑point. Fine tune the terms using a method of enumeration. Cut steady‑state error by 98.6 % and boosted temperature‑control stability by 58.6 %.

Chamber‑Wide Temperature Calibration
         • Created a self-adaptive correction model that maps the single sensor reading to the entire chamber’s spatial average temperature. Ensures the controller acts on a reference that can accurately represent the entire space.