For this week’s homework, we learned how to utilize a Computer Numeric Control (CNC) machine to create a delicate yet sturdy piece that expressed our personal interest and tested our design abilities with new software. To complete this assignment, I chose a design that challenged and allowed me to manipulate it to my liking.
Step I: Choosing the Design
As a Space Studies student, choosing my design was easy; I found an astronaut icon from thenounproject.com and loaded it onto Carbide Create V7 to manipulate it to my liking.
Step II: Manipulating the DesignÂ
After uploading the design onto Carbide Create, I set up my working area as a measuring 3.5″x5.5″x0.75″, which were the measurements of the wood, and rotated my piece 90 degrees to use as much space of the wood as possible. I then added pockets at 2 different depths (0.150″ and 0.170″) to make the astronaut stand out. Later, I selected the cuts of the design and added tabs to stabilize my piece while cutting. Finally, I looked at the simulation of my cut, and I was able to have a preview of the path the machine would follow to cut out my piece.
Step III: Cutting
After the design was complete, I set up the CNC machines to cut 2 pieces simultaneously and save time. Paige was a huge help during this process; she walked me through the process and gave me the confidence to do the whole process on my own.
To set up the machine, I changed the bit on the large CNC machine to a 1/8″ bit, as suggested by Fernando, to have a cleaner cut, then followed the instructions on the homework file to finish setting up both machines, including securing the wood and aligning the corner on the machine to the wood.
When my pieces were cut, I vacuumed up any sawdust left in the machines. A problem I encountered with the small machine was that it didn’t cut the piece all the way through, so I sanded the piece from the back to push it out; I also attribute the cut not going all the way through to my wood being slightly warped.
Step IV: Post-Processing
Once I pushed my pieces out, it was time for sanding. It is important to note that the piece cut by the bit Fernando suggested (cut in the large CNC machine) was smoother and, therefore, easier to sand. I used 120 and 280-grit sandpaper to achieve a smooth and even look to both of my pieces.
Finally, I stained my astronaut with a brown wood stain. I faced some difficulty wiping the stain off the small crevices, but I completed it and let it dry!
Cost Analysis
7
| Cost Type | Cost | Price | Source | Quantity | Total |
|---|---|---|---|---|---|
| Materials | 1×4 Board | $7.97/8ft | homedepot.com | 3 yds | $33.97 |
| Screws | ~$5.00 | homedepot.com | 1 pack | $5.00 | |
| Sandpaper | $3.50 | homedepot.com | 1 pack | $3.50 | |
| Labor | Woodworking Operator | $15/hour | ziprecruiter.com | 2 hours | $30.00 |
| Prototyping Engineer | $20/hour | Self | 4 hours | $80.00 | |
| Overhead | Facility Cost | $10/hour | practicalmachinist.com | 3 hours | $30.00 |
| Quality Control | $15/hour | ziprecruiter.com | 1 hour | $15.00 | |
| Design | Engineering and Development | $25/hour | ziprecruiter.com | 2 hours | $50.00 |
| Iterations | $20/hour | Self | 1 hour | $20.00 | |
| Misc. | Waste and Scrap | $5.00 | Self | N/A | $5.00 |
| Total | $272.47 |
Once the design has been finalized, the cost of subsequent iterations is significantly reduced. The major cost savings come from the reduced design and development time, as the initial design phase accounts for understanding the software and adjusting parameters. In future runs, labor costs for the Prototyping Engineer, Engineering and Development, and Iterations will be minimal since the design and settings can be reused. Additionally, material waste and facility costs may decrease as the process becomes more efficient. This would likely reduce the total cost per piece by about 40-50%.
