How I 3D Printed A Headphone and Key Hanger
A Model Prototyping Process Blog
Task at Hand
This week, I tackled the task of 3D printing a hanger for my headphones and keys. The challenge was to design a model in a 3D modeling software that was functional.
Design
Why I Chose To Make a Hanger
Before approaching any software, I decided to sketch out some basic ideas for a model. I knew that I wanted to build some sort of hanger for my keys because I constantly lose them in my room. I also wanted to make the hanger able to hold my headphones because they usually end up somewhere in my bed where I can’t find them (and frankly, I’m surprised I haven’t accidentally sat on them yet).
Form Rationale
I knew that my hanger would need a flat section large enough to attach a command strip to secure to my wall, a round section for my headphones, and some hooks for my keys. After playing around with a few different sketches I settled on the following forms (Figure 1):

The form of the sketch on the right reminded me of an octopus so I tried adding tentacles. Eventually, I scrapped this idea because I realized the tentacles would be too fragile and would also give the 3D printer more opportunities to fail. I decided to chose function over decoration and ended up keeping the simple form of the hanger on the right. As a small reference to my process, I kept some of the ornamentation by keeping the eyeballs from my octopus in my design. I modeled this design using Solidworks, exported it as an STL file, and printed my model.
Final Model
The following images show my final model (Figure 2).



I am very happy with the way the model turned out and use it regularly. The 15% infill settings left a visually interesting pattern on the flat part of the “octopus” head. My only complaint is that the supports necessary for printing the little hooks left marks on the model itself after I took them off. Aesthetically, it is not the best looking model. However, functionally, the model works perfectly.
Reflection
Hurdles Along the Way
I have previous experience with Solidworks and 3D modeling, so this aspect of the project wasn’t particularly challenging. What I didn’t expect however was how off I would be with estimating the dimensions for my hanger. On my first attempt, I assumed that my hanger would need to be about 3.5 inches wide by 4 inches tall. This was a gross overestimation. My first attempt turned out way too large for my headphones (blue model) (Figure 3).

Pros and Cons of the Software I Used
On my second attempt, I reduced the dimensions of my model in Solidworks itself. Because I designed the model with good design intent, I merely had to change a few numbers in my sketches and the software adjusted the rest of my model accordingly. One of the pros of Solidworks is its parametric nature allows you to define each detail with precise dimensions and relationships. This aspect ensures accurate dimensions and quick alterations when designed correctly. One of the downsides of Solidworks is that it doesn’t allow for more free form manipulations. For example, I would have loved to make a dome like shape instead of the flat surface on the “octopus” head. With a modeling software such as Fusion 360, this would have been way easier because you could push and pull the model’s surfaces as if they were clay.
What I Wish I Knew
I should have suspected something was off with my first print because its print time was 20 hours. In retrospect, I wish I had measured the size of my headphones instead of eyeballing them. I also wish that I was better acquainted with appropriate printer settings for making my model. On the first attempt I used a 30% infill which definitely contributed to the 20 hour print time. On the second attempt, I used a 15% infill and smaller dimensions, which brought down the print time to 3 hours.
What I Enjoyed
My favorite part of this project was seeing the finished 3D part. 3D printing generally gives me a lot of anxiety because I have had many experiences in the past where the print fails. There’s so many different things that could go wrong, especially when the print time is long. Luckily, in this project I was able to get my model right in just two tries. Needless to say, I was very happy when I saw the completed model.
