Introduction

For this ENGI 210 assignment I was challenged to carve out a shape in a material such as wood, using a Computerized Numerical Control (CNC) machine. I was prompted to choose a shape from the noun project, an online database of nouns in image form. The wonderful thing about the noun project is that every image you find can be exported as an “svg” file, which is exactly the type of file you would want for the CNC machine.

Design

After browsing online for a while, I stumbled upon a dolphin. As dolphins happen to be my favorite animals, I knew then and there that I was going to use this shape. However, I realized that I wanted to add something to the dolphin to create something that resembles a “painting,” but then in wood. So, I browsed a bit more and found another shape that I could combine with the dolphin to create something more “my own.” So after adding and adjusting some things in Adobe Illustrator, I had created a scene of a dolphin jumping out of the ocean at sunset.

Because I wanted the wood surrounding the dolphin to be cut out, while the dolphin itself remained, I had to reverse the colors in Adobe Illustrator because the CNC machine cuts everything that is black on the image. Once I had completed this step, I was ready to export the final svg file and transfer it to the CNC machine.

Cnc-machining

The “Carvey” CNC machine that we have in the OEDK operates with a software called “Easel”, this software allows you to import an svg file and make final adjustments before carving. In Easel, I had to report the dimensions of my piece of material from which I was going to carve. In my case, this consisted of a piece of pine wood. After completing this step, I was able to adjust the carving depth to my desire. Taking into consideration the time it takes to carve and considering the aesthetics of my design, I decided to cut about 1/4 of an inch deep. I decided to use a 1/16 inch downcut carving bit to do the carving. Finally, I had to clamp down the wood onto the CNC machine, making sure it was secured enough so that the forces of the drill did not change the position of the wood.

Results

Fortunately, the carving worked out on the first try and I was very content with the results. I immediately did a second iteration, and it worked again. However, because the second wooden piece was naturally varying in thickness, the carving was deeper in some parts than in other parts. Coincidentally, this created a very cool effect that made it seem as if the carve was “shadowed” by a very faint carve. To better understand what I’m explaining, you can take a look at my pieces behind number 3!

Once we are taught how to post-process wood, I look forward to bringing this image to life using color.

Cost analysis

For the raw material, I used two 13.5 cm by 9 cm by 2 cm pieces of wood, which amounts to about 500 cm^3 or 0.0005 m^3 of wood. The absolute bottom price I could find for pinewood is about $450 per m^3, which would amount to $0.225 cents for the raw material. However, this would only be accurate in case of mass production because consumer, store bought wood has already been cut multiple times and goes at a higher cost.

Let’s say I was working for a Texas minimum wage again at $7.25 per hours, the labor costs would amount to $21.75, since I spent about 1.5 hours creating my design before spending another 1.5 hours using the Carvey. This time includes preparing the material for cutting (clamping, etc.) and two 23 minute periods of actual cutting time. In total the costs add up to $22 for two pieces, or $11 per carving.

*Since the Carvey has already been purchased by Rice, I will consider the costs of using the machine as negligible.