Hi everyone,
I hope you all ready to embark on our peanut’s origin story. Over the course of 4 weeks, we selected our chess piece, created 3d printed and cnc cut positives, silicone molded the positives to create negatives and lastly molded our final chess pieces that we present to you today.
At first, we did not realize how simple the cnc cut needed to be which limited what we could select for our chess piece. Originally we thought we could do bb8 but because a lot of the grooves and dips would not easily cut we would sacrifice a lot of the resolution to be left with an abstract snowman. Jolina and I decided against this because we wanted a piece we could be happy with which let us to our peanut.
This was past Gate 1 and we had a mission to catch up. At first, the original peanut had an open hold so it would not properly import into Solidworks.I sliced the peanut in half using Meshmixer’s Plane Cut feature to creat a symmetrical half that we could use instead for our peanut.
I spent a lot of time working through Solidworks trying to perfect our peanut half and conjoin it to the mold base as you see in the image. I followed the instructions very closely and realized that Solidworks is very particular about imports and intepretinbg everything as mm. Once I discovered which files import with size I was able to scale the peanut accordingly so it could be implemented into the software with no issues.
3D Printing
3D Printing was relatively simple given the homework enabled us to be comfortable printing. It was the simplest part of the project and we used the Bambu Printer for both our full peanut and the half on the mold base.
It was a relatively smooth and simple process, so no complaints here!
CNC
The CNC process was quite a difficult one. To start, I imported the half peanut into VCarve. However, we imported the .stl file from SolidWorks (the one we used for the 3D printing). This did not work, however. Also, the video did not show the very beginning stages of setting up, so it took forever for us to actual upload any files into Shapeoko. We didn’t know we had to press “ok” after setting up the dimensions of the brick.
Once we figured that out, however, we set up the file to be CNC-ed. In our first round of CNC, it seemed that the .gcode file did not export correctly, and because of this, the first round of CNC got messed up. It was cutting in the wrong place, and it cut cleanly down the middle during the finishing process. It also went off the grid of where it was supposed to be cutting.
Our second trial, however, was much better. In our second trial, we adjusted the settings and used a thicker drill for the initial run-through, so the process was faster. In this, the CNC cut correctly. However, since our finishing run only used the object boundary, it did not finish until the very bottom, leaving a little band of uncut wood. In this case, it is not obvious, but in the future, if we had more time, we would have opted to finish the whole piece instead of just the object boundary.
Making our Silicon Negative:
With our 3d printed and CNC machined half, we were ready to make our silicon negative. In this, we poured equal parts of A and B according to the math we did. However, our 3D printed half of the project was smaller than the CNC half, so we had to adjust to optimize the amount of silicon we used. Once we measured it out, we poured it into the cardboard mold we made. Then, we waited for it to set. Once it was set, it was ready for the positive.
Making our Positive:
In this, we used equal parts of A and B of 305, and did that according to the volume of our piece. We used rubber bands to hold the two halves of silicone together and mixed the dye into part A. We decided to use pink and purple for our final pieces. This step was very smooth sailing. Everything went as planned, as we poured each individual piece, waited, and repeated. Our first piece came out a bit misaligned, but as we kept molding, they got better and better.
Outro:
Since we are so clean, here are some pictures of our clean workspace during the project!
Here’s our cost analysis:
3d printed full chess piece + 3d printed positive with base: ~ $4.85 (195 grams of PLA)
Wood 2 x 6 in by 3.5 in : $13.62
Silicon: ~ $39.66
Polyurethane: ~ $18.07
Labor (7.5 x 20) ~ $150
Total: $226.6
