The Drying Rack That Has Every Runner’s Back

In week five of my physical prototyping class, I was tasked with making a 3D printed object that would be useful in my everyday life. The only design requirement was as follows: design something that would be useful in your everyday life - it must serve some function rather than just being art or for decoration. 

Design

While brainstorming for this assignment, I thought of many things that I do every day. I wake up, I make a matcha latte, I go for a run, and many other things. The event that I decided to focus on is going for a run. The act of running has become so integrated into my life that I almost don't notice how many times I interact with my running gear. One object that I interact with almost daily is my running water bottles, which slip into my running vest. These small water bottles are very hard to keep clean because I use them so often, and they usually hold electrolyte drinks. In particular, I struggle with how to dry them as there is no good way to hang them from my drying rack. 

Salomon Soft Flask water bottle: How can I dry it more easily?

Based on these observations, I decided to focus on this goal for my 3D printed object: 

• Holds both of my running water bottles and their caps so that they can easily dry out overnight without getting moldy. 

Therefore, this design would be useful in my everyday life when I am not running, specifically when I have just gotten back from a run. 

For this prototype, I will be evaluating its usability. 

Usability: Works as a drying rack and holds two Salomon running water bottles in such a way that they can air-dry overnight, allowing airflow through the water bottles and the caps. A user can easily remove and replace each object without difficulty (even with sweaty hands). 

• I measured my goals by filling both water bottles with water and then emptying them and placing them on the drying rack and leaving them overnight. Then, checking them in the morning and seeing if they are dry on the inside. I also tested these steps after going for a run.

Unique Feature: I modeled this drying rack to fit along the edge of my sink so that water can flow down the ramp and into the sink.

Sketches

After researching some existing products, I began by sketching some initial ideas for this prototype.

Sketches I made throughout the design process.

Prototype

First, I observed the location where I hoped to place my prototype. I wanted it to drain any excess water into my bathroom sink, so I measured the width of the sink ledge. I also measured the water bottles to determine the desired height. Based on these measurements, I made my first low-fidelity prototype out of cardboard. When testing it, I instantly noticed that the small branches at the top of the poles were too wide. I had to bend the cardboard to fit it inside the mouth of the water bottle. This led me to measure the width of the water bottle openings to ensure my next prototype would fit inside.

Analyzing the location for the prototype, making a low-fidelity prototype, and creating a first 3D model.

Next, I began my 3D modeling process. This was my first experience with 3D modeling, and I used Onshape to design the entire prototype from scratch. There were a couple of features that I aimed to add to the model: a ramp to let water drip down into the sink, and branches to hold open the water bottles and allow for airflow. After I was satisfied with my model, I printed my prototype. I printed it at 86% scale because I wanted the height to be ten inches to hold the water bottles off the base, but the maximum height of the printer was 8.6 inches.

Adjusting and finalizing the first model to be printed, then printing it.

My first print was a success, and I was excited to test it out. The water bottles slipped on and off easily, and there was enough space for both caps on the base. I went for a run and washed the water bottles, and then set them to dry overnight as a first test.

Testing the first printed prototype in the desired location and leaving the water bottles to dry overnight.

Then, I held an online review session with three people. They helped me brainstorm how I could add more features to the drying rack and make it more effective. 

They identified two main issues with this prototype: 

1. There is no air circulation around the caps, so they might not dry.

2. The poles are not tall enough to hold the bottles off the ramp, so they might not get enough air circulation.

This was confirmed by the results of my test the following morning: the water bottle still had some drops of water inside when I checked it.

I also received feedback from a professor and gained the following advice:

• Adding little branches mid-way up the poles could add even more airflow by holding open the sides of the bag as well as the top.

• Making the bottom of the ramp thicker could make it more durable and long-lasting.

Based on these testing sessions, I iterated my 3D model to allow for more airflow. To allow more circulation around the caps, I lifted them off the ramp by a circle of cubes to allow water to flow down the ramp. I considered adding grooves to the ramp, but I hoped that this solution would allow for easier cleaning. I also chose to lift the water bottles above the ramp instead of extending the poles. This would conserve sink space and resources. I created a cube-shaped model before switching to a horizontal pole model, as seen below. I also increased the grade of the ramp.

Left: an iteration of the added features to improve airflow.

Right: The final 3D model with increased airflow features.

I attempted to print my model a second time, however, the print was unsuccessful (as seen below). My third and final printing attempt was successful (and matched the color of my bathroom soap).

My failed print which stopped before finishing the base, and the start of my final successful print.

Final prototype at the sink location.

Details of my final prototype can be seen below: cubes to lift the caps and horizontal bars to lift the water bottles.

My daily life included a run, so I tested my final design after washing the water bottles. The following morning, they were dry, so I concluded that this prototype was successful!

Details of the added airflow features.

Analysis

I tested my final prototype with four design students. This consisted of four five to ten-minute testing sessions, for a total of 30 minutes of testing. Each participant was asked to grade this prototype out of 6 based on the assignment rubric. Based on this, I gathered the following insights:

Quantitative data: 

Participant 1: 6/6

Participant 2: 6/6

Participant 3: 5/6

Participant 4: 6/6

Things That Worked Well:

• Addressing the possibility of mold growth by allowing airflow

• One participant mentioned that the unique feature is very thoughtful and makes the design more usable and desirable

• The final iteration shows significant improvement from the first couple designs. 

• One participant mentioned that it helps resolve a paint point that they hadn't considered.  

Things That Could Be Improved:

• One participant noticed that “you have to be gentle/slow with it” and suggested that it could be improved by making the sticks slightly thinner. 

• Another participant mentioned that it is “slightly hard to get the bottle on and off.”

• Two participants mentioned that the caps could be held in a more secure spot so that they don't slide off, suggesting a rack or compartment. 

• One participant suggested that I test it with other types of bottles. 

• Someone suggested adding adjustable length for different-sized bottles. 

In conclusion, my prototyping process was successful to create a drying rack that dries my Salomon running water bottles overnight. The final prototype is a design that I will use in my daily life, therefore meeting the design requirements for this assignment. It also highlighted a unique feature; it’s measured to fit along the edge of my sink to allow water to flow down the ramp and drain into the sink. 

If I had more time for this project I would:

• Adjust the length of the branches to allow for easier placement of the water bottles on the poles. 

• Iterate the feature that allows airflow to the caps to ensure that the caps do not slip around. 

• Allow for the drying rack to be printed at 100% scale by making the poles detachable. This would allow for the poles to be taller, and the design would collapse into smaller pieces for easier storage. 

Overall, my final drying rack prototype met my goals of prototyping for usability and I received positive feedback during my critique, therefore I will not be completing another iteration of my drying rack for this assignment.

Reflection

Through this process I learned how to 3D model using OnShape software. I also learned how to slice an STL file and print it using an MK4 3D printer.

I chose to create this object because it meets a pain point that is prevalent in my daily life, and I am passionate about running and athletics which increased my motivation to design this product.

The biggest challenge I faced was printing my final iteration when my print failed. This helped me realized that time is an important resource. I enjoyed seeing my sketches turned to life through this project. It was satisfying for me to see my own progress and learn how to iterate within constraints such as time and size.