For our final EDES 210 project, Lizzy and I decided on a Fred the Frog figurine as our chess piece. We sourced the file from Thingiverse and did some alternations such as removing the CAD’s original base and sizing up the entire figurine, to truly make it ours.
Before starting the molding and casting process, we had to establish the size we hoped our chess piece would be. Due to our design being particularly stubby, we had to iterate on the sizing multiple times to get the right height for a chess piece.
After the piece was size correctly, we then started to prepare the positive of our mold. MeshMixer was used to split the figure in half and Solidworks was used to add the surrounding rectangle. We choose to split the frog, such that the more detailed end could be 3D-print, while the simpler end would be CNCed.
Therefore, the positive of front end of the mold, with the face and toes, was 3D-printed. Our first version of this end turned out to be too small, and we had to scale it up. Scaling it up allowed us to make a better negative mold out of silicone. To make this side of the negative mold, we mixed equal parts of a silicone solution, let it set, then demolded.
Then, to make the other half of the positive we started by preparing the file in VCarve. This half contained the back of the frog, which was basically a just a curved surface. This file was then uploaded to a CNC machine and carve out of wood, which took 4 hours. Then the same process was used to create the other negative half of the silicone.
The mold turned out well separately, however when we tried to place the pieces together, we realized that the pegs and holes were on the same side instead of opposing each other, therefore they were unable to be inserted into each other. To remedy this issue, Lizzy gerry-rigged one side so that the holes and pegs were swapped, and then the mold worked as intended.
Once both halves were set, we were then able to begin the process of making the actual pieces via casting. Our first version of our frog chess piece turned out decently well. We used the 30-minute pot-time polyurethane, and the process of measuring the parts, mixing them, and then letting the cast set was very simple. We attempted this same process to make the other iterations of our chess piece, however, adding the color caused some excessive bubbles. However, there frogs still turned out fairly well.
We decided to make our final two frogs using the 30 second pot-time polyurethane to try to get rid of some of the bubbles. The rush of making sure to mix both parts and the color and then pour the solution into the mold all before it cured was really fun. Also, it was really cool to see the polyurethane cure right before our eyes.
After removing each frog from the mold, they required some clean-up which was done with an Exacto knife. Finally, Lizzy made each frog look cute and unique by adding color and detail with acrylic paint.
Overall, this final project was fairly enjoyable. There were lots of steps in the process of making our chess pieces, but the gates and demonstrations really helped us stay on track. We worked well together and made some pretty awesome frogs.
Clean workspace below:
Cost Breakdown: Raw Materials * PLA - $20.00 * Wood - $8.00 * Silicone - $40.00 * Polyurethane - $75.00 * Acrylic Paint - $12.00 * Polyurethane Dye - $10.000 Labor * 20 hours x 10.00/hour (2 people) = $400.00 Tools * Nomad CNC Machine - Owned by the OEDK ($2,800) * Bambu 3D Printer - Owned by OEDK ($2,00) Total: $565.00
