I chose to make a coaster for this project. To start I went to the noun project to select a design. I am a fan of Liverpool FC so I found a vector file of the Liverpool badge (https://thenounproject.com/icon/liverpool-5317742/). I then imported this into Carbide Create to adjust the file accordingly to get it ready to be machined. I followed the steps in the provided instructions to get my file ready. Some of those steps included changing the page size to the size of the blocks of wood we were given. To get these dimensions I used calipers and to get an accurate wood depth I measured in multiple locations across the wood and took the average. I also had to set the tool paths to machine the way I wanted. It was at this step that I realized the initial crest would be too complicated for the drill to cut as there were lines that were within 1/8” of each other. To alter my design, I removed the outside shield and kept the bird, then I added a circle around it for the coaster. I set the outside tool path to be cut out, or machined to the full depth of the wood. The inside toolpath of the bird I made as a pocket.
With the file ready I was able use the CNC machine. Before running the file, I put my block of wood in place by screwing it tight into place and taping a plank of sacrificial wood below it. I also had to calibrate the tool, by placing a specific block in the corner of my wood and placing the drill bit into the corner pocket. This allowed for the device to know where to cut on the wood and be calibrated. With the 1/8” in and the calibration performed I ran my file and watched it do its job. The one mistake I made was putting the outside coaster toolpath too close to the edge of the block so on one side it cut slightly into the sacrificial wood. This did not alter the final design at all but showed me the importance of knowing tolerances in my designs but also the importance of having sacrificial wood to avoid much bigger issues. After the job was done, I vacuumed up the sawdust, removed my pieces and cleaned up any mess. I repeated this for the 2nd block but adjusted the wood depth to be specific to the 2nd block of wood.
I now had two unfinished pieces and had to post-process to finish the job. I started by removing any undesired bulk pieces of wood such as the tabs. With those gone I was ready to sand, I used an 80 grit and then 150 grit paper to ensure it was smooth on every side of my coasters. I then coated the coasters with golden oak stain to give the wood a really nice color and to finish the wood.
Cost Table:
| Cost Type | Cost | Price | Source | Quantity | Total |
| Materials | 1 in x 12 in Wood | $12.98/foot | Homedepot.com | 7/12 | $7.57 |
| Wood Stain | $7.98/8 oz | Homedepot.com | 1/8 | $1.00 | |
| Sand Paper (80 grit) | $6.68/6 pack | Homedepot.com | 1/6 | $1.11 | |
| Sand Paper (150 grit) | $6.68/6 pack | Homedepot.com | 1/6 | $1.11 | |
| Labor | Post-processor | $23.79/hour | Indeed.com | 1 | $23.79 |
| CNC Machine Operator | $22/hour | Ziprecruiter.com | 1 | $22 | |
| Overhead | Facility Cost (Machine Time) | $4.85/hour | Rockler.com | 1 | $4.85 |
| Quality Control | $13/hour | Zippia.com | 1/6 | $2.17 | |
| Design | Engineering and Development | $35/hour | Red Fox Innovations | 1 | $35 |
| Misc. | Waste and Scrap | $13.50/hour | Ziprecruiter.com | 1/4 | $3.38 |
| Total | $101.98 |
Cost Analysis
Looking into the cost of my two coasters I found it seemed to be more expensive than I had thought in part due to the file design aspect. Materials was straightforward to calculate and I got all my prices from home depot. For the wood blocks I found a 1 in x 12 in block which is a rough estimate of 2 blocks with a depth close to 1 inch and width of 5.5 in each (11 inches total), and then would cut it at 7 inches length to get 3.5 inches length on each block. The labor was split into labor using the CNC machine and labor post processing and was found on hiring sites. Overhead costs come primarily from using the CNC machine and can account for the costs involved in using the machine such as bit costs and setup costs. The design engineer was one of the more expensive aspects of the project but was a necessary cost to design the vector file and tool paths. Waste management for 15 minutes was the last component of the project to bring the total to just over $100. In bulk, these prices could be cut down significantly, for example the file could be use repeatedly which would cut out the design engineer for future creations.
