For this project we were inspired by this minecraft chess set.
At first we wanted to mold and cast the Enderman, but we got feedback in class that it was most likely not going to work due to air bubbles in the too-thin arms. So we decided to go with the creeper instead. We ran into a small issue due to the limitations of creating a mold from the CNC– the gap in between the legs couldn’t really be filled so we redesigned the creeper in Solidworks with no gap.
We created the positives in Solidworks. We 3d printed one half and using hot glue + cardboard walls, then filled it with silicon to create the mold.
For the other half, we used the Nomad CNC to carve out the mold in a 2″ thick block of wood. We had to convert the stl file into g-code using v-carve. Since the shapeoko broke the day we were going to do this, we had to redo the file to use a 1/8″ roughing pass and a 1/16″ finishing pass. We used hot glue + cardboard walls again and created the mold, this time using a different silicon since the first one ran out.
Here are what the two halves looked like at the end of the process.
Lastly we casted using a 1:1 ratio of part A and part B castable resin. Our first 5 pours were okay but not great, as we noticed some air bubbles in the face of the creeper even after shaking the mold around.
To get around this, we tilted the face part of the mold down while pouring which helped significantly.
Lastly, we did some sanding around the edges to reduce the edge caused by the two molds contacting each other.
COST ANALYSIS
Raw Materials
- PLA for 3d printer = $3.50
- 1 foot of 2”x4” plank of wood = $0.50
- 400ml Part A and Part B of Silicone mold = $20
- 200ml Part A and B castable resin = $4
Labor
- $15/hour x 15 hours = $225
Overhead
- Workshop access(3d printer, CNC) incl. misc tools (cardboard, hotglue, rubber bands) – $50
Total Cost = $303
