For this week’s assignment, we worked on using the CNC machine to cut out a noun of our choice from a block of wood.
Step 1: Choose a design
The first step in the assignment was to determine a noun to cut out. I chose a yin-yang icon because it is simple but a great example to demonstrate the capabilities of the CNC machine!
Step 2: MODIFY THE FILE IN CARBIDE CREATE
Once I decided on my icon, I downloaded my .SVG file and imported it into the Carbide Create software. Next, I went into the settings and adjusted the stock size and thickness to be that of my material (i.e., a block of wood). I changed the width to 3.5″, height to 8.5″, and thickness to 0.74″. Then, I scaled my .SVG file to 3×3″ so as to fit within the newly set stock (i.e., within the dimensions of my wood).
Next, I went into the toolpaths window to create my contour and pockets. I made the pockets first followed by the contour (cut-out). For the first pocket, I used a start and max depth of zero to work as a constraint for the second pocket. Without the first pocket, the second pocket would work over the first rather than around.
As mentioned above, the first pocket allowed the second pocket to cut around the circle. The second pocket was used to make the yang (highlighted in blue) with a max depth of 0.125″.
For the contour, I used the stock bottom of the material as the max depth and set an outside/right offset direction.
Lastly, I used the simulation tool to visualize and confirm what I sought for my file!
Step 3: SET UP NOMAD CNC MILL
With my file now ready, I saved the G-code and used the Carbide Motion program to set up the Nomad CNC mill. First, I taped down a piece of scrap wood to the mill’s table and taped my block of wood atop the supporting wood. Next, I initialized the machine. Then, opened my file and appropriately jogged the machine in order to use the BitZero tool for probing. Once probed, I started the job! The cutouts took ~ 30 minutes.
Step 4: POST-PROCESSING
The last step in this assignment was to post-process. I began by sanding my blocks using 120-grit sandpaper. I followed that with 220-grit, and lastly 400-grit. Next, I used a danish oil finish to stain my block. 
After two coats of danish oil spread 15 minutes apart, I let it dry for 24 hours. The following morning, I used three layers of clear coat ~20 minutes apart.
And with that, I had two identical CNC-made yin-yang blocks of wood!
Cost estimate
- 4 Pack Unfinished Wood (4×8″) = ~$18
- Cost to Use a CNC Mill per hour = ~$35
- Danish Oil Finish = ~$14
- 12 oz. Protective Enamel Gloss Crystal Clear Spray Paint = ~$7
- Labor (6hrs x $20/hr) = ~$120
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TOTAL = ~$200
