11. Open Source Hardware - From Fibers to Fabric¶

I. Introduction (Open Source Circular Knitting Machine)¶

This week marked a transition from working with raw fibers to understanding the mechanical systems that give textiles their structure, introduced through a lecture by Sara Diaz from Studio Hilo on how open-source technologies invite new ways of processing and producing textiles.

From mechanically aligning and twisting fibers into yarn, to interlacing, looping, compressing, or embedding them into stable surfaces. Our focus was on knitting specifically, exploring how open-source approaches can reinterpret its loop-based structure. Through this lens, we were interested in understanding how accessible, open-source knitting systems can translate traditional textile techniques, and accordingly chose to reverse-engineer the Macro Yarn Machine by Jasmine Martinez.

The Macro Yarn Machine is a circular knitting machine designed to produce seamless tubular fabric by knitting in a continuous round motion instead of flat panels. It uses multiple needles arranged in a circular formation, allowing it to produce seamless, stretchy, and uniform knitted fabrics quickly.

Key Features

Shape: Needles are placed around a circular bed → makes a tube-shaped fabric.

Speed: Much faster than hand-knitting.

Fabric Type: Creates jersey, rib, interlock, and other knitted structures.

Use: T-shirts, socks, sleeves, sweaters, sportswear, and seamless clothing.

Variety: Small hobby machines (Addi, Sentro) → large industrial machines used in textile factories.

Historical Background¶

Historically, the circular knitting machine emerged in 1816 when engineer Marc Isambard Brunel patented the Tricoteur, a device that revolutionized the industry by creating seamless tubes of fabric at speeds impossible for hand-knitters. For nearly two centuries, the technology evolved toward industrial efficiency prioritizing speed, fine gauges and mass production.

Research and References:¶

A. Macro Yarn Machine by Jasmine Martinez¶

The Macro Yarn Machine is an open-source textile fabrication system developed for producing large-scale yarn structures. It knits around a central core and can feed multiple yarns within a single row. The mechanism is driven by a spur gear that carries the rotating assembly, while the cylinder group remains fixed to the work surface. As the gear rotates around the stationary cylinder containing the needle guides, this coordinated motion enables precise vertical control of the needles during circular knitting.

The project is deeply rooted in open-source hardware culture and would not have been possible without existing community knowledge, particularly Circular Knitic by Varvara Guljajeva and Canet Solà, and the HILO Spinning Machine, developed through close collaboration with Sara Diaz Rodriguez. Designed as a large-scale, readable knitting system, the Macro Yarn Machine exposes the mechanics of circular knitting while encouraging replication, adaptation, and further development within the open-source textile community.

A redesigned version of the machine was developed in 2025 by Hilo Studio in collaboration with Sarah Prien.

B. Circular Knitic by Varvara and Mar¶

Circular Knitic is an open-source, digitally fabricated circular knitting machine designed to integrate textile manufacturing into contemporary maker culture. Built using accessible tools such as 3D printing, laser cutting, and Arduino, it enables knitting to be approached as a form of soft digital fabrication. Developed as an open hardware project, Circular Knitic is fully replicable and invites community-driven experimentation, reintroducing textile fabrication into Fab Labs and makerspaces traditionally focused on hard-surface production.

Our Objective¶

Our objective was to deconstruct the mechanical logic of knitting by understanding how synchronized movements, guide profiles, and needle geometry organize linear strands into three-dimensional fabric. The project applied product design and reverse engineering methods within a collaborative team, working from an open-source digital design back to physical reality. It required adapting to real constraints, time, files, materials, and available equipment, while engaging in rapid problem-solving, collective decision making, and resource management. This process built technical awareness and enabled us to adapt a global open-source machine design to local conditions.

II. Team Introduction¶

This project was developed collaboratively within Makerspace Amman team, working closely alongside Doaa Al Hinty and Haneen Khaleel and of course our instructor Claudia Simonelli.

III. Process and Workflow¶

The development process was non-linear and iterative, building on existing open-source documentation of the Macro Yarn Machine by Jasmine Martinez and adapting it to local material constraints as follows:

Phase I: Research & Digital Deconstruction: Analyzing existing repositories and STL files.

We started off by following the Visual Building Instructions by Jasmine for the multi-yarn circular knitting machine, then reviewed and downloaded the available STL files from her GitHub Repository preparing the digital assets for local production.

The assembly relied on two main component groups: 3D-printed parts and standard hardware.

3D Printed Parts

Big Bottom Gear

3x Bottom Gear Fix

4x Wheel Structure

Outer Cylinder

4x Holder for Threaded Rods

4x Inner Cylinder

Needle Guide Bottom

Needle Guide Top

Middle Layer

Lid Holes

Funnel

Needle Holder

4x Yarn Wing Guide

4x Yarn Tension Holder

4x Spool

4x Spool Holder

Small Motor Gear

Hardware

8x Threaded Rods M8

12x Wing Nuts M8

20x Flange Nuts M8

4-16 Brother KH230 Needles

4x Book Scews

16 Ceramic Eyelets 5mm

8x Deep Groove Ball Bearings 4x9x4mm

12x M3x6

12x M3x12

8x M3x8

4x Thrust Ball Bearings F8-16M 8x16x5

3x M4x12

4x M4x20

4x M4 Nut

Phase II: Understanding the Mechanism: Prior to starting the work it was crucial to understand the anatomy and the machanism systems.

1. Drive System (Gear Assembly)

A spur gear mounted on the main shaft drives the machine’s motion. As the gear rotates, it carries the entire rotating assembly around the central knitting area. This rotation is the primary power source that moves the needles and yarns through the knitting cycle.

2. Fixed Cylinder (Needle Bed)

The machine has a fixed cylinder group attached to the table. This cylinder contains needle guides that hold the knitting needles in place and define their path.

3. Needles (Latch Needles)

Latch needles are mechanical knitting needles used in circular and flat knitting machines. Each needle has a small hinged latch that opens to catch the yarn and closes to form and release loops, enabling continuous automated knitting. The knitting needles ride in the needle guides. As the drive gear rotates around the cylinder, the needles are moved vertically and radially, opening and closing their latches to catch the incoming yarn and form loops.

4. Yarn Delivery

Multiple yarns can be fed simultaneously into the path of the needles. The machine arranges them so that as each needle cycle happens, the yarn is caught, pulled through the preceding loop, and released to form fabric. This enables multi-yarn rows and more complex knitted textures.

Phase III: Material Sourcing and Adaptation: Inventory audit and sourcing local equivalents.

We applied a “Warehouse First” approach, reviewing available inventory against project requirements and making necessary component substitutions accordingly.

A. Needle Specification Comparison¶

The original design called for the Brother KH230 14 cm needle, we used a locally available alternative that was 1 cm shorter. This difference did not affect functionality, as the needles needed to be further trimmed by around 2 cm for the machine.

Phase IV: Fabrication & Prototyping: 3D printing, acrylic laser cutting, and manual metalwork.

A. 3D Printing¶

Started off by printing all the Stl files from the Repository, arranging and slicing the files on Cura Ultimaker.

3d Printing and Slicing Settings

Printer: Ultimaker S5
Material: PLA
Make sure the model is placed flat on the build plate (Z = 0).
Adjust slicing settings:

Layer Height: 0.2 mm

Wall Line Count: 2

Top/Bottom Layers: 4

Infill Density: 20%

Infill Pattern: Triangles

Print Speed: 70 mm/s

Initial Layer Print Speed: 6 mm/s

Fan Speed: 100%

Initial Fan Speed: 0.0%

Printing Temp: 205°C

Build Plate Temp: 60°C

Build Plate Adhesion Type: None

Disable supports.

Click Slice and save the file.

B. Laser Cutting¶

Certain components were fabricated by laser cutting instead of 3D printing, either due to their larger scale or the improved accuracy offered by the laser cutter. These include: Middle Layer Component, The Gears.

Prepare gear design for laser-cut:

5mm Acrylic Laser Cutting Settings

Power: 100%

Speed: 1.0%

Frequency: 1,000 Hz

Passes: 1 pass

Ready for test parts¶

Phase V: Design Engineering and Adaptation: Redesigning components to fit available hardware.

A. The "Bearing Shift"¶

Because we utilized larger deep groove ball bearings than the original design, a complete redesign of the Wheel Assembly was required. This modification rippled through the assembly, eventually requiring the removal of the top needle guide to maintain mechanical clearance.

B. Redesign the Book Screws¶

Modify the book screw design to fit the rod diameter.

C. Threaded Rods vs. Power Screws¶

In this project, we explicitly chose Threaded Rods for better motion over Power Screws (Lead Screws).

Threaded Rods: Designed for tension and fastening. Their finer pitch provides high friction, which helps maintain the fixed structure of the machine frame under vibration.

Power Screws: Designed for motion transmission with low friction. While smoother for movement, they were unnecessary for our static structural supports and would have increased costs.

Threaded rods were purchased in 1m lengths and processed into 25cm segments. Machine used for cutting: JET JWBS-14SFX 14" Steel Frame Bandsaw

D. Deep Groove vs. Thrust Bearings¶

We chose Deep Groove Ball Bearings over Thrust Bearings.

Deep Groove Ball Bearings: Best for high-speed, smooth rotation where the force is pushing straight down onto the axle. They are cheap and available but can "wobble" if you push them from the side.

Thrust Bearings: These look like a "sandwich" of two washers with balls in the middle. They are designed specifically for axial force (pushing along the shaft).

Phase VI: Assembly & Manual Calibration: System integration and tolerance tuning.

A. Inserting the needles and Assembling the Inner Cylinder¶

B. Assembling the wheels¶

C. Assembling the bottom gear¶

D. Assembling the Needle Guide and Rods¶

E. Cylinder with Bottom Gear Assembly¶

F. Yarn Assembly and second layer¶

Phase VII: Validation & Motion Mockup: Testing the needle movement and mechanical synchronization.

IV. Final Result¶

V. Materials BOM¶

Qty	Description	Price	Link	Notes
1 Sheet: 30 x 60 cm	Acrylic	15 JOD	N/A	Lab Warehouse
700 gm	PLA Filament	25 JOD	N/A	Lab Warehouse
50 x 24 cm	Plywood	4 JOD	N/A	Lab Warehouse
8 pieces	Deep Groove Ball Bearings	4 JOD	N/A	Lab Warehouse
2 Rods: 1m length	Threaded Rod	2.5 JOD	N/A	Local Supplier
20	Bolts	1 JOD	N/A	Local Supplier
50 hrs	3D Printer Usage	N/A	N/A	Lab
30 min	Laser Cutter Usage	N/A	N/A	Lab
10 min	Jet Steel Frame Bandsaw Usage	N/A	N/A	Lab
4 Cylinders	Thread Yarns	4 JOD	N/A	Lab