Oct 2024: Bendabottle
Skills developed: Product Design, Market Research, Fabrication (Modeling, Adhesion, Physical Prototyping)
Context:
At Wharton, I balance my classes in entrepreneurship and strategy classes with hands-on product development as part of the Integrated Product Design Certificate. This program supports my engineering roots and adds a design-focused perspective to my MBA.
Taught by Professors Ashley Marcovitz and Karl Ulrich, OIDD 5150 Product Design covers everything from the fundamentals of fabrication (for physical products) to product management and market scalability (including digital products). The class is a popular listing across the University of Pennsylvania and I joined a diverse cohort across Engineering, Design and Wharton.
We were assigned to teams of 4 to develop a functional aesthetic product for college students, priced under $50. At the end of the semester, the university hosts a product design expo at Penn Museum, where the general public could vote for their top 5 favorite products.
Bendabottle is our final project, and this page documents our design-to-prototype process.
Brainstorming a water bottle:
The assignment was to create a single, functional, and aesthetic product for college students, priced under $50. This demographic simplified user interviews and market research, but a preliminary search on Amazon or Temu makes it evident why innovating a completely new product category in the space is a challenging assignment. I had to reckon with the classic reality that while nothing is new under the sun, I could always try to execute a known idea better.
One of our first lessons in class was that entrepreneurial ideas stem from a direct need that the founder(s) experience, and I am notorious for forgetting my water bottle. Water bottles are a necessity, but metal ones are heavy, and plastic ones are environmentally harmful. Drawing inspiration from hikers and outdoor enthusiasts, we envisioned a fully-compressible water bottle—portable, reusable, and sustainable.
Initial prototype design and feedback:
Our initial prototype used the top half of a Fiji Aqua bottle with a cardboard base.
For compression, we created a “skeleton” along which the material can fold. This prototype’s skeleton was made from triangular cardboard pieces attached to the body but we intended to use very thin (1/16th inch) acrylic to create the final version. These triangles would later become part of our logo and its colors were an aesthetic feature.
Our initial tests were very promising. Users found the dimensions of the bottle too large and hoped for more complete compression in the final product. The prototype was constrained by the plastic top of the Fiji bottle itself. We hoped to solve this by cutting the bottle out of silicone sheets.
Material testing and adhesion:
Our initial material tests were rough.
Silicone was ideal for its durability and water resistance, but its high surface tension made adhesion nearly impossible. We tested hot glue, Epoxy B6000 and Epoxy E6000, all of which dried on the material to no effect. We tried to reduce the surface tension by intentionally scratching away at the surface of the material. Yet for a whole week, every prototype we cut came undone. The surface tension also made it difficult for the bottle to remain in a compressed form.
We considered pivoting to Tetrapak, which folds as well as cardboard and is as waterproof as silicone. We abandoned the idea due to budget constraints and industrial ordering requirements. We tried to simulate the material by attaching a sheet of silicone to thin cardboard, but without the right adhesive, that also fell apart.
By the time we discovered a special silicone adhesive (it cures in 30 seconds), we were too late for our midterm demo. So we improvised a second version of our prototyping by stapling together the silicone body and attaching all external components with duct tape.
Caps and compressions:
Although we fixed adhesion, compression was still an open question. Our real-world competitors (like Stojo) were using silicone blends rather than pure silicone, which explained why their foil held shape once folded. Constrained by our budget and sourcing such a material, we added a rubber band to the top of the cap to loop around the compressed bottle.
We modeled our bottle cap in Rhino. Learning to use the software is one of the academic goals of the class and most of us were using the education free trial. With an amateur interest in animation and many incomplete Blender projects, I hoped that the basic modeling operations I’d learn in Rhino could be transferable. We had weekly modeling assignments to ensure that we could create something that could be safely submitted to the Stratasys 3D printers in our lab.
The initial cap was too large for the silicone body. We also cycled through 2 prints for size, number and depth of screw-ridges for the cap top.
Final finishing touches and the Product Design Expo:
Our final week of class was preparation mainly for the Product Design expo. We created various prototypes for our marketing materials, including a foam board for our stall, “sell sheets” (which were postcard-sized versions of our ad that would help prospective customers remember the product at the voting booth) and stickers.
We also estimated a cost model of our bottle to competitively price it at $15. For comparison, Stojo is usually priced at $13 and drives a sustainability-focused marketing strategy. Lookalikes at Amazon are generally at $11 and at Temu are priced at $2. The cost model template I used primarily includes cost of materials only and not cost of time worked.
Acknowledgements
This project was made possible through the incredible support of my team—Miranda Papapetropoulou, Clara Baurmeister, and Indrani Paul Roy—and our mentors, Professors Ashley Marcovitz and Taylor Caputo. Special thanks to all the lab techs at Tangen Hall, our TA Iryna Donska, and everyone who attended the expo or followed our progress on Instagram.