Introduction When I started brainstorming for this project, I wanted to challenge myself by having the design to meet the following criteria:

• The print had to have a uniform, maximum height with a thin profile (3-5 mm high at most)
• It had to not look like it came from a flat pack/die-cast kit format when assembled
• It had to have a functional mechanism and serve a practical purpose

With this criteria, I landed on designing a charging cable spool container. I knew I wanted it to have a cylindrical profile but due to the uniform height constraint, I had to think outside the box (or tube, as it were). After some quick research, I learned about the Kerf-Cut technique for bending wood in woodworking; I quickly adapted this concept to FDM printing by adopting design principles for living hinges. The result is a unique cylindrical profile that provides a textured surface for improved grip and also orienting the layer lines of the wall components to be orthogonal to the direction of forces applied through normal use, boosting the strength of the design.

The result of my design process is a device that is completely functional immediately after assembly without any auxiliary adhesives needed; the assembly can be held together through press-fits alone.

Assembly Instructions (See "Assembly Photos" Section in Gallery Above)

1. Remove all components from frame; wire cutters and/or needle nose pliers are helpful in this process, but not necessary.

2. Take base plate (denoted by circular central slot) and the wall components. Bend the wall components such that they fit into the outer slots of the base plate.

3. Repeat the bending and slotting process for the second wall component. Note that the smaller flaps that go across the cable inlets created by the gaps in the cylindrical wall need to be tucked behind the adjacent wall component.

4. Take the small, curved spool components and place them thin-walled side down into the circular slot of the base plate.

5. Orient both spool components such that there is a clear through-line from the cable inlets of the outer walls through the gap between the spool components.

6. Run the charging cable of your choice through the cable inlets, opening the wall flaps as needed, and through the central gap of the spool assembly.

7. Take the top plate (denoted by the central hole and identical outer wall slots) and align it such that the wall slots press-fit into the wall components.

8. Ensure the spool assembly passes through the central hole of the top plate.

9. Take the crank cap (denoted by the toothed grip on its outer edge) and align it such that the semi-circular central slots line up with the spool assembly. Press firmly to engage press fit.

10. Turn the crank cap to wind up your charging cable. Note: Do not over-torque, as this can cause the spool assembly to fail. Failure can be mitigated by adding glue to the spool assembly and the crank cap.

Documentation Commentary

a. Initial design sketches from my brainstorming process; a mix of concept sketches and preliminary drafting. b. OnShape CAD - Cross section of partial assembly to evaluate tolerances and fitment comparability between components. c. Layout Planning sketch in OnShape to design the die-cast card component. d. Final die-cast assembly with all components present. e. Close-up shots of different connector profiles I designed for the various component geometry to achieve single-piece removal of the entire kit from my build plate, but also ensuring easy removal of each component. f. The aftermath of my iterative design process; the double-edged sword of rapid prototyping!