HCDE 451: 3D Printing

Anna Schmitz
Nov 5, 2019 · 5 min read

In HCDE 451, we talked about 3D printing. Earlier, it was a fascination of makers of all disciplines, but has since become a norm for industry and especially for students. The machines allow easy iteration of complex parts with very little material. A person only needs to know about computer-aided design (CAD), and a little about how the machines work.

Students had nearly free-range over which topics they could create a 3D printed object for, but were limited to household and useful objects. Examples are: a pen holder, a ruler, a cable organizer, a soap dish, a toothpaste squeezer, cookie cutter, and many more.

I chose a different kind of organizer — one made for jewelry. I realize that many women get annoyed with loose jewelry floating about their homes. But more importantly, that jewelry organizers are needlessly expensive and almost always purely for decoration. It can be hard to find something that is simple, cheap, and hides itself neatly away. I set out to design such an organizer for necklaces.

An example of an overly-complicated jewelry organizer by H Potter on Amazon

The class provided PLA plastic filament for the printers. PLA is almost entirely made from vegetable oil, making it inexpensive and easy to work with. I figured, however, that my product should be a little bit visually interesting. A user should enjoy encountering it, rather than putting up with it. I therefore decided to use a special filament — PLA with copper. This filament contains 20% microscopic copper particles, meaning objects it prints come out with a glossy auburn-red finish. This material should be something that compliments the shiny metal of jewelry.

Obviously, necklaces are best organized using gravity to keep them still, meaning they should be hung from something. My idea is to use a wall-hanging device to keep them from tangling, while still being accessible and not overly-complicated.

Rendering of model necklace holder

The design is scoop-like with five slots cut into it. Each of the resulting prongs can hold a different necklace. The scoop shape is to prevent the necklaces from sliding out on their own. The back is flat and can be taped or stuck to a wall. I planned to use sticky foam strips (Command strips) to hang this up.

I used Solidworks to model this. It’s the CAD software I am probably most comfortable on. At first, I was eager to give Rhino a try, because I’m familiar with CAD and therefore would expect to find some functions that I’ve seen on other programs. Upon trying it out, I found that Rhino sort of works “in reverse” from other CAD programs. It asks for locations and dimensions first, before you specify what modification you’re making (such as an extrusion, revolve, cut, etc). I’d like to experiment with it more on my own time, but for simplicity’s sake, I stuck with Solidworks for this project.

I’ve 3D printed several times before and felt comfortable doing so with this project. I oriented it with the wall-facing side touching the print bed. The prongs were at a shallow enough angle to not need any printing supports, which saved the amount of filament I used. Because I was using a new material, I was a bit skeptical of how the result would turn out.

3D printed result

This model printed out quite well. It was sturdy enough to hold several necklaces and had no obvious flaws to it. The size was exactly what I expected. The material, too, looks intriguing and a little more “dressed up” than normal PLA plastic. All in all, I’m happy with how the print turned out. (The photos shown above depict the model with its wall-facing side down.)

The real test is determining how well it performs once it is stuck to a wall. I took a few Command strips and laid them along the wall side. At first, they seemed to adhere to the PLA material quite well. I pressed the strips in firmly, then peeled off the opposite side and pressed it against the wall. Within a few seconds, it seemed plenty sturdy enough for jewelry. I hung a few pieces from it to test.

Jewelry hanger with command strips, and stuck to a wall.

As I hung more jewelry on it, the device still held up. Overall, it was doing its job quite well. In the future, I would modify the design a bit so the gaps between the prongs would be wider. Some of my necklaces have large clasps or tags on the ends, which occasionally got caught in the narrow gaps. The gaps would only need to be another 1/8" wider or so.

In creating this, one of the challenges was to get a good 3D print started. I had to switch out filament, lay new masking tape down on the print bed (which ensures the 3D print will stick) and get it started going the right speed. In one of my first attempts, the print speed was way too high, and the filament was travelling too quickly to adhere to the bed. Once I found a better speed, I sat with the printer for a while to make sure it was looking good, then I left it to finish.

I really enjoyed working with the copper PLA in this project. Aside from its interesting looks, I’m evermore curious to see how other types of PLA hold up in 3D printers. I know of filaments infused with wood, silver, brass, and magnetic iron shavings. Experimenting with some of these might enable me to make different parts with unique characteristics. Overall, this was a fun exercise in CAD and 3D printing, and I hope to make more useful items like this in the future.

    Anna Schmitz

    Written by

    Human-Centered Design + Engineering at University of Washington. A relentless creator, musician, and reinvisioner of a better world.

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