Hi everyone!
This was the first time I ever used a CNC machine, or even heard about it honestly. It was a nice homework and very straightforward to design, create and post-process. I chose to create a coaster for any canned drink or small glass, with the moon and some stars, as shown below in the figure. I took the SVG file from NounProjects.com and modified it on the Carbide Create software to crave and cut the proper parts as I desired.
Figure 1. SVG edited file on Carbide Create
I then went ahead with the CNC machine calibration and all initialization steps.
Figure 2. Calibration and initialization processes
My piece took approximately 36 minutes to complete, thus 72 minutes, or 1 hour and 12 minutes in total for both pieces. After having both my coaster parts I went ahead and used sandpaper to smooth out all my surfaces.
Figure 3. Total amount of minutes per piece (top); Wood block right at the start of CNC machining (middle); Wood block half way in CNC machining process (bottom)
Then, I took the pieces outside and used a natural wood stain for a more finished look. I let the paint soak for half an hour and then cleaned the pieces with a towel until all the excess came off and the wood was dry, as suggested in the instructions on the back of the product can. I can say I really liked the final result and I am excited to have built and post-processed something I will be actually able to use at home :). It was a nice overall homework assignment and I really enjoyed it.
Figure 4. Resulting coaster
Cost Analysis
| Cost Type | Cost | Price | Source | Quantity | Total |
| Materials | Scrap wood | $0 | Rice OEDK | 2 blocks | $0 |
| Sandpaper (220 grit) | $4.99 | Amazon.com | 1 sheet | $4.99 | |
| Natural classic wood stain | $11.98 | Home Depot | 1 can | $11.98 | |
| Labor | Working Operator | $8/hr | Glassdoor.com | 1 hr 30 min | $12 |
| Prototyping Engineer (You!) | $8/hr | Glassdoor.com | 30 min | $4 | |
| Overhead | Facility Cost (CNC machine) | $65/hr | Ultimate Precision Tech in Houston | 1 hour | $65 |
| Design | Iterations | $5/iteration | Estimation based on cost of materials used each iteration | 0 iterations | $0 |
| Misc. | Waste and Scrap | $0 | Estimation | N/A | $0 |
| TOTAL | $97.97 | ||||
