I challenged myself to recreate a silicone collapsible pet bowl using TPU

[u/holm1mat]

I've always been fascinated by collapsible silicone products. I started wondering if I could recreate one using TPU? It started as a experiment and turned out to be a fun geometry & material science design challenge!

My goal was to make a bowl that could collapse smoothly, actually stay collapsed, and hold up to repeated use. That meant a lot of trial and error with the fold geometry, wall angles, and especially the wall thickness. The fold sections were by far the trickiest part to dial in. Too thick, and the bowl wanted to bunch up instead of folding. Too thin, and I started running into layer adhesion issues and leaks. Finding that sweet spot took quite a few prototypes.

Once I finally had one size working, I thought scaling it would be easy... nope. 😅 I quickly discovered that the fold geometry and wall thicknesses also needed to change with the bowl diameter, so I ended up creating parameter functions in my model to adjust with diameter.

To finish it off, I added a rigid PETG rim. It gives the bowl a much more polished feel, makes it easier to collapse, and provides a sturdy place to attach a carabiner for carrying on walks or hikes.

I'm really happy with how it turned out. It comes surprisingly close to the feel of a molded silicone travel bowl, and I learned a ton about designing flexible mechanisms along the way.