design choice
For our final project, we brainstormed a couple of ideas, but quickly landed on making something related to the animal kingdom. As I was scrolling through Thingiverse.com, I came across the design of complete animal chess by David Musaffi. Out of available figures, we picked a penguin pawn. Penguins are adorable and we were excited to see how our work would turn out!
prototype
We made our prototype on FDM 3D-printer with yellow PLA. The resulting piece was slightly smaller than what we wanted, but smooth and easy to print. After the discussion with a teaching team, we were recommended to get rid of the small hat because of the limitations of the CNC machining with such objects.
two positive halves
Using Mesh Mixer and Solid Works and following instructions in documents and during in-person sessions, we divided the file in halves, put them on the bases, added pour and air channels, and cut a hat off our penguin. Big thanks to Gloria for working out the intricacies of both softwares, it was a quite challenging task!
First half was FDM 3D-printed, while the other one was cut out of a wood on a NOMAD3 CNC machine using a file processed on VCarve. While some groups experienced issues with their CNC, we were able to get a reasonably short (1hr 40 min) CNC cut of our penguin half. Working with NOMAD3 had its challenges from tricky VCarve software to issues with homing and probing the tool to forgetting to save some toolpaths in the process. Eventually, we did get our positive halves using both methods.
Molding and casting
Using our halves, we made negative silicone molds. Both times it was a simple 1:1 ratio of Part A and Part B, poured over the half in the box of the indeterminate size and left overnight. We appreciated the relative easiness of the process. Next, we combined two molds, taped it together, and poured polyurethane in it to make final figures. The result was repeated multiple times until we got 8 presentable pieces of our penguins. We got a cute little colony of penguins!
post-processing
For our post-processing, we cut the pour channel tail off, sanded, and spray painted our penguins. We decided to make classy black penguins that are prepping for their graduation with Rice Owls!
Our workspace after cleaning up:
cost model
| Cost type | Cost | Price | Source | Quantity | Total |
| Materias | PLA | $14.99 | Amazon | 1 spool | $14.99 |
| Silicone casting | $44.99 | Amazon | 1 kit | $44.99 | |
| Urethane casting | $38.69 | Amazon | 1 kit | $38.69 | |
| Wood | $1.00 | HomeDepot | 2 bricks | $1.00 | |
| Labor | Prototyping Engineer | $20/hr | Gloria and Bakai | 5 hrs | $100 |
| Worker | $10/hr | Gloria and Bakai | 15 hrs | $150 | |
| Overhead | FDM 3D-printer | – | OEDK | 5 hrs | – |
| NOMAD3 CNC | – | OEDK | 4 hrs | – | |
| Solidworks | – | OEDK | 2 hrs | – | |
| Waste management | Cleaning | $10/hr | Gloria and Bakai | 1 hr | $10 |
| Total | $359.67 |
