This semester has been full of a lot of firsts for me, and using a CNC machine is one of those. Considering my interest in CAD and CAM, this is a particularly useful skill to familiarize myself some more with. Originally I wanted to cut out a model of the Hylian shield from The Legend of Zelda, however, after witnessing the limitations of the 1/8 inch endmill bit I decided to do something simpler as I didn’t have the time to troubleshoot for the small and intricate design in the original shield; so I redesigned it to simplify it.
Hylian Shield model
By the time I got to work with the machine, I witnessed how several of my classmates struggled with it, and the way they solved the problems that they encountered. From thin walls, bad adhesion to bad initialization and zero-ing of the machine I saw how to take precaution on every step of setting up the machine. I took all of this into account when redesigning my shield.
Simplified shield toolpath
The first shield being cut
I was very happy with the first shield that got machined, I didn’t run into any problem I witnessed from my classmates. However, this was not the case for my second piece. I don’t know if it was the state of the wood itself, but the second shield broke on certain internal walls and even chipped on one of the edges when contouring. Still, no other problems encountered, I decided to go along with it, let’s just say now I have a pristine and a “worn and damaged” version of the shield.
The second shield with its flaws
To release the shields, I saw the similarities to Gunpla and applied a technique that Gunpla enthusiasts use to reduce the amount of nub/tab marks when cutting them out. After releasing the shield from the stock I sanded them down with 180 grit, 280 grit and 400 grit sandpaper to make them feel a little smoother.
Sanded down pieces
To finish them, I used masking tape as a mask (who would’ve thought it was useful for that?) certain parts of the shields and paint sections of it according to the corresponding color on the original design; mainly because by this point I was a little too tired to get on the Vinyl cutter, try to get the dimensions right to mask it using vinyl. In the end I’m happy with the result, and twisting the narrative so one shield is pristine and the other worn makes me feel a little better about one of them not coming out perfect.
Painting the shields
The Final Product
| Cost | Price | Amount | Source | Quantity | Unit | TOTAL |
| 1″ x 4″ x 8ft Yellow pine lumber | $5.08 | 96 | Lowes.com | 10 | ft | $0.53 |
| Rust-Oleum Spray Paint (negligible) | $6.48 | 3 | Lowes.com | 0 | cans | $0.00 |
| CNC operator | $24.00 | per hour | Ziprecruiter.com | 1.5 | hours | $36.00 |
| Post-Processing (Painter) | $18.00 | per hour | Ziprecruiter.com | 1 | hours | $18.00 |
| Facility & tooling cost | $250.00 | per month | txrx.org | 1.5 | hours | $0.52 |
| CNC machine energy | $0.28 | per hour | circlemwoodworking.com | 1.5 | hours | $0.42 |
| Quality Control | $18.00 | per hour | Ziprecruiter.com | 0.5 | hours | $9.00 |
| NET TOTAL | $64.47 |
