PART I: Introduction
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It was a long journey for the plasma cut. At the beginning of this semester, the compression air system in OEDK was broken. Thus, we were not able to do the plasma cut after class. Besides, the sand-blasting machine was affected. In addition, when I went to the one-on-one training, I realized that my original design did not align with the requirements. Therefore, Luke just quickly showed me how to use the plasma cutter and end the training. Honestly, I did not feel confident enough to operate the plasma cutter independently after training.
The compressed air system is finally back up and running! I’m grateful to the OEDK staff, who worked through midterm recess to make it happen. Under their guidance, I am not only familiar with operating the plasma cutter but also learned how to set up the machine before cutting my pieces.
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↑↑↑ Power supply ↑↑↑ Compression air ↑↑↑ Cutter
PART II: Workflow
- First: Object selection
Originally, I chose Deathly Hallows as my cutting objective. However, according to this homework requirement, I have to put my object in a specific diamond. Also, I still need to consider the kerf of the plasma cutter. So, I had to give up Deathly Hallows. Finally, I put “NASA” in my diamond.
↑↑↑ The original object ↑↑↑ Final object
. - Second: Cutting
Under the OEDK staff’s guidance, I finished my metal pieces. Below is the video of when I did the plasms cut.
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- Last: Post-processing
According to the requirements, I have to use three ways for post-processing. The methods below were what I did.A.
After cutting my pieces, I used pliers to remove the residue on the metal pieces. Later, I used the gear polisher to polish the surface. Also, attempt to remove the rust on the pieces.
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B.
After that, I did the send-blasting to make all the surfaces become even. In the photos shown below, you can see the difference before and after send-blasting.
↑↑↑ Before ↑↑↑ After
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C.
Last, I chose spray painting to finalize my metal pieces. In order to make an outer space background on my metal, I used black color to paint the first layer. Later, I used white color to create tiny spots on the surface.
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PART III: The Work Space
The space was cleaned after used.
PART IV: Cost Estimation
| Cost Type |
Cost | Price | Source | Quantity | Total |
| Materials | 12 in. x 24 in. 28-Gauge Galvanized Sheet | $19.93 | Home Depot | 1 piece | $19.93 |
| Black Spray Paint | $5.98 | Home Depot | 1 ea | $5.98 | |
| White Spray Paint | $5.98 | Home Depot | 1 ea | $5.98 | |
| Labor | Machine Shop Plasma Cutter Operator | $20/hr | ZipRecruiter.com | 2 hr s | $40.0 |
| Prototyping Engineer (You!) |
$25/hr | Indeed.com (Engineering Intern) |
1 hrs | $25.0 | |
| Overhead | Machine Time | $260/hr | cnczone.com | 2 hrs | $520.0 |
| Quality Control | $22.5/hr | Glassdoor.com | 2 hr | $45.0 | |
| Design | Engineering and Development | $25/hr | Indeed.com (Engineering Intern) |
1 hr | $25.0 |
Total: 686.89
The total for completing the plasma cut objects is $ 686.89. Most of the manufacturing cost was Machine Shop Plasma Cutter Operator. Since I was not familiar with an operating plasma cutter, I could only produce 3 pieces in 2 hours. However, once I get it, I can increase my production by making the same pieces in 2 hours. Thus, the cost of each metal piece will decrease significantly.
In addition, I also spent many times on Quality Control, but I believe it is challenging to cut costs in this area. Otherwise, the product’s quality can not be sustained.
