FrED

FrED is a Desktop Fiber Extrusion Device developed to teach manufacturing and feedback control systems to remote learners. Inspired by desktop 3D printers, FrED enables students to alter fiber extrusion parameters for hands-on learning. Originally deployed at MIT, FrED needed to be expanded to Monterrey Tech in Mexico, prompting a low-cost variant for large-scale production. FrED comprises extrusion, cooling, spooling, and control systems, using sensors to refine fiber diameter. The project’s goal was to reduce FrED’s cost from $5,428 to under $200, with objectives covering redesign, prototype testing, supply chain setup, and a pilot production of 25 units.

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Team Members

Russel Bradley, Rui Li, Tanach Rojrungsasithorn

Affiliation

MIT Device Realization Lab, Tec Moterrey

Motivation

Make FrED accessible for educational institutions, enabling hands-on learning. By reducing production costs and scaling up manufacturing, the project aimed to meet the growing demand for FrED units in teaching environments at MIT, Monterrey Tech, and beyond.

My Role

Design and manufacturing of the extruder, heat block, tower frame, cooling system

Prototyping

The first prototype used an Aluminum 6061 heat block with nichrome wire, offering high resistivity and oxidation resistance. The T-shaped tower support with adjustable holes allowed control over the heat block’s position to influence fiber diameter. Prototyping involved SLA printing with high-temperature resin. In testing, the heat block melted the preform, but manual feeding was required, and the nichrome setup posed insulation and temperature control challenges. Additionally, the tower length was insufficient for fiber cooling without active cooling, indicating a need for refinement in the extrusion sub-assembly.

In the second prototype, a redesigned heat block with a single heater cartridge was used, along with a taller, wider tower support to fit a diameter measurement sub-assembly. The tower was split for SLA printing and assembled with bolts. A DC motor replaced the stepper motor to lower costs, but challenges arose with stability due to the tower’s weight and complex motor control requirements. The SLA-printed parts needed excessive support material, which was difficult to remove. These issues, including the need for a simpler motor control solution, informed the development of the third prototype.

In the third prototype, a modified Creality Ender 3 hot end was used to accommodate the 7mm glue stick, replacing the heat break pipe with PTFE for insulation. A lighter, laser-cut acrylic tower support was introduced, and a spring-loaded extruder with a stepper motor improved pre-form handling. Parts were assembled with solvent cement, and the nozzle size was drilled larger. Testing showed successful extrusion but revealed issues with polymer leakage from the PTFE pipe and structural instability. The tower’s attachment and height required reinforcement for stability and effective fiber cooling, prompting further design iteration.

In the fourth prototype, the Creality Ender 3 hot end was used with a steel heat break pipe and Marine Weld for sealing. The nozzle was removed to simplify the design. A taller tower support with added brackets improved stability, and PETG was used for 3D-printed parts for better heat resistance. An adjustable spring tension system was included in the extruder, and active cooling was added with a fan to cool the fiber before diameter measurement. Testing showed successful, uninterrupted fiber extrusion, and Marine Weld was chosen for sealing to enhance strength as well as temperature resistance in final user testing.

Manufacturing

Factory Setup

A factory was set up in Building 35 - 017, with distinct stations assigned to each sub-assembly on the production line. The extrusion sub-assembly parts were stored in red bins, and fiber cooling parts in green bins. A section of the factory housed six Prusa 3D printers for PLA and PETG printing.

Pilot Run and Time Study

A pilot run of 15 FrEDs was conducted to test the production process. Each sub-assembly was completed, and a time study was performed to evaluate the efficiency of the production steps. This run helped identify areas for improvement and provided insights into potential adjustments to the workflow.

Bottleneck Identified

The time study revealed that the Marine Weld step is the primary bottleneck in production. Applying Marine Weld carefully to seal the steel pipes requires significant time and precision. Moreover, this step involves a 24-hour curing period to ensure full setting, slowing down the overall manufacturing process.

Process

A systematic product development life cycle (V-model), as listed below, was defined for the development of a low-cost variant of FrED.

Defining functional requirements
Conceptual design of the low-cost variant of FrED
Iterative cycles of prototyping and testing
Process plan and sourcing plan
Assembly line setup and pilot production

Keeping in mind the principles of Design for manufacturing and assembly (DFMA), the following four points were focused on while design the low-cost variant of FrED:

Usage of standard parts wherever possible
Reducing the total number of parts while still meeting the functional requirements
Taking a modular approach for easy deployment, repair and if required replacement of modules
Integrating parts as much as possible

User Testing

A user manual was prepared and engineering students who had no prior knowledge about FrED were brought in to assemble FrEDs. Each student was given the FrED kit.

Feedback was incorporated into the final production level design of FrED. The user manual was updated to have more pictures in it. The tower support was updated to have the default positions of the different sub-assemblies etched on it.

Final Production Design

Feedback

The feedback highlights both positive and negative points regarding the assembly process. Positive comments noted the user manual’s straightforward, user-friendly design, with one-sided printing and clear aesthetics praised by users. Specific improvements included adding laser-engraved shapes and detailed images to enhance clarity.

Negative feedback focused on assembly challenges, including confusion with positioning and wiring. To address these, instructions for laying down the assembly while plugging in wires were emphasized, and color-coded labels were added for easier identification of wire plugs. Issues like bracket alignment and clearer direction for pulling the PCB drawer were identified for future improvements.

New Design

Existing Design

New Design

Results

Cost reduction of 95% and weight reduction of 50% was achieved. The prototypes of the design were built and tested extensively. The process plan has been defined and documented. The supply chain for the materials has been set up. The assembly line has been set up in MIT Building 35. 25 FrEDs have been successfully manufactured and are ready to be deployed to the end users.

	Old Design	New Design
Minimum Extruded Fiber Diameter	~0.2 mm	0.15 mm
Weight	~10 lbs	5 lbs
Unit Costs	$5428	$269

Old Design		New Design
~0.2 mm	Minimum Extruded Fiber Diameter	0.15 mm
~10 lbs	Weight	5 lbs
$5428	Unit Costs	$269

Results

Cost reduction of 95% and weight reduction of 50% was achieved. The prototypes of the design were built and tested extensively. The process plan has been defined and documented. The supply chain for the materials has been set up. The assembly line has been set up in MIT Building 35. 25 FrEDs were successfully manufactured and are ready to be deployed to the end users.

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