For our final project, we were tasked to work with a partner to create 8 identical plastic chess pieces using molding and casting methods. To do this, Aaeisha and I selected a chess piece on Thingiverse, modified the file to be 3D printed and CNC machined, used silicone to mold the 3D printed piece, and made 8 plastic copies of Patrick. Compared to other fabrication methods taught in this class, this method was relatively quick and easy. It was also great to have results that we were proud of, even if we weren’t able to try the dye part of the assignment.
Selecting a Chess Piece
We decided to use Patrick Star for our chess piece and selected this copy on Thingiverse. After, we downloaded the file as an .stl and imported this file into Fusion 360. We did not use the MeshMixer in the pre-processing step as we noticed that the file did not change after following these steps. Fusion 360 was also able to accept the file as it was.
Modifying File to Be 3D Printed
Because we were not as familiar with SolidWorks, we used TinkerCAD to design the plate that would be attached to the back of our chess piece. After following the steps in the instructions to complete our file on Fusion360, we moved the file to Easel.
Modifying File to Be CNC Machined
We also converted this shapefile into g-code which was checked by a TA for accuracy.
Molding and Casting
After 3D printing our Patrick chess piece, we began the molding and casting process. We started by creating the silicone mold. First, we used cardboard to create a makeshift box with one open end. I then hotglued my 3D printed piece onto the center of the base of the box. We poured a silicone mix using two equal parts and waited overnight before removing my 3D printed piece. We then poured liquid plastic equal parts. This hardened into our finalized piece in 10 minutes. After, we sanded the piece where needed.
In Hindsight
Generally speaking, we were content with our process in building these chess pieces. However, there were some initial inconsistencies in the depth of the Patricks while we figured out the amount of plastic would be sufficient for the model. We also would have loved to incorporate colors into the design.
Cost Analysis
Labor: 6 hrs * $20/hr = $120
3D printing: $2.50 (PLA material)
Silicon mold: $5 – estimated from $50 bottles
Liquid plastic: $15 – estimated from $150 bottles
Total cost: $142.50
