Coffee Cup Conundrum

This is the first “problem set” assigned to students for the Special Topics in DIY Design and Fabrication class at CMU. The students were given a couple different design goals with different target audiences and were required to select one of the target audiences.

Being a pretty typical mechanical engineer, I decided to go with the design that required assembling.

As always, I start the ideation process with sketching; however, I had to document the sketches much more that I am usually accustomed to, as the process of sketching out my ideas is part of my grade.


The first thing I did was write down the requirements of the design. After that, I wrote up some other design considerations to sort of guide the design. Once those requirements were out of the way, I could start actually sketching out some ideas.


One of the first considerations was where the fingers would go. Initially, I thought having two fingers above the indentation and two fingers below would be the most stable. The size of the cup would force me to change that later.


Once I had the basic idea down, I had to figure out how to actually make this cup holder out of multiple parts and how it might be assembled. This was an idea for having two mirrored parts that would snap together around the cup. The acrylic parts, however, would be really long and skinny, making them structurally unsound.


Here, I tried to get an idea of a fastener for attaching the different parts. The sort of wedge-shaped clip would make it to the final design.


I wish that could have been the final design. I guess the “assembly” could have been interpreted as stabbing the cup with the pencil.


In retrospect, this probably should have been my final design. The reason I had ruled it out was that one of my personal requirements from earlier was to have a design that could be assembled onto the cup without picking up the cup. With careful measurements, this would have been possible in this design, but I decided to go with something a little more flexible.


Instead of having one piece retaining the top of the cup, I decided to go with two pieces, so this could definitely be assembled onto the cup without picking up the cup.


That’s the isometric-esque sketch o the product. I ended up having to remove one of the steps in the handle to compensate for the size of the cup, which was much smaller than I expected.


That was the model made in Solidworks. Of course, it did not end up fitting that well, and I did not have quite enough time to make multiple cuts to make sure everything fit really snuggly. The translucent part was the handle part before bending. I used a heat gun to get the bends in the final product.


And there’s the final thing. There were definitely quite a number of issues in the design, as i was no all that stable and was in fact a little too fragile. Plenty of the other submissions in the class were far better… so I decided to step up the amount of effort I was putting into this class by quite a bit for my next submission.


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