For this project, I set out to test the plasma cutter’s limits by crafting an optical illusion-inspired shape. My goal was to explore the cutter’s performance on complex designs, with varying trace lengths. Through this experiment, I observed that while the plasma cutter delivers consistent results on larger sections, the quality of shorter cuts tended to vary.

(1) Angle Grinding

After plasma cutting, I used an angle grinder to clean up dross. Unfortunately, the amount of dross produced relative to the amount of metal I wanted to preserve on my piece forced me to devote a significant amount of time to cleanup, as I wanted to remove as much residue as possible without corrupting the actual desired shape of the piece. Luckily, though, with the angle grinder and a magnetic grinding block, the task itself wasn’t that hard to complete.

(2) Sandblasting

Following grinding, I moved to sandblasting to remove any rust or surface impurities, achieving a smooth texture ideal for painting. Based on my peers’ experience, I was expecting this step to take quite long, but it really didn’t! Because my piece consisted of a lot of blank space, there was not much to actually sand blast, so, in comparison with the angle grinding, this step was a bliss. After getting it done, I was really happy with the result; I could finally touch my pieces without risking a few cuts (I had my fair share of those), and the design I had chosen could be appreciated!

(3) White Spray Paint

Once sandblasting was complete, I began painting. I applied three coats of white spray paint to each side. I painted one side over a day, applying coats every twenty minutes, and repeated the process for the other side on the following day. Painting proved tricky due to humidity and other people working on their pieces as I was working on mine, which slowed drying times and (and this one made me a bit angry) led to my diamond being stained with violet spray paint on one side. I tried to resolve this the best way I could by sanding down the surface, and then applying a final coat for a smooth finish.

(4) Glossy Clear Coat (2 Coats)

After allowing the white paint to dry, I finished with two coats of glossy clear coat. Because of what I had previously experienced, I made sure to wait about half an hour between coats, and did the whole process late in the evening to try to minimize the odds of people working close to my work station as the diamond dried up. The glossy finish provided a nice look I was aiming for, so I was happy enough to conclude my work in process.

(5) Clean-up

To wrap up, I thoroughly cleaned and organized all workstations, including the loading dock and the place over the spray painting area I had been at. I made sure to throw away the empty cans I had encountered while looking for the colors I wanted to work with, and called it a day.

Cost Estimate

 

Cost Type	Item	Price	Source	Quantity	Total
Materials	Steel Sheet	$10.47 per 1 sq ft	HomeDepot.com	15 sq in	$1.09
	White Spray Paint	$5.98 per can (12 sq ft)	HomeDepot.com	90 sq in	$0.31
	Glossy Clear Coat	$5.98 per can (12 sq ft)	HomeDepot.com	60 sq in	$0.21
Labor	Metal Shop Operator	$15.00/hr	Ziprecruiter.com	1.5 hr	$22.50
	Prototyping Engineer	$12.00/hr	–	3 hr	$36.00
Overhead	Facility Cost (Machine Time) 40 min sand blaster 1 hour angle grinder 20 min plasma cutter	$80.00/hr	Practicalmachinist.com	2 hr	$160
Quality Control	Inspection	$24.00/hr	Ziprecruiter.com	1 hr	$24.00
Design	Engineering & Development	$30.00/hr	Ziprecruiter.com	20 min	$10.00
Total (excluding overhead costs and using my own rate)	$71.610 total  ($35.805 per piece)

This per-piece cost excludes overhead, as overhead expenses would be minimal in mass production. In a real-world production setting, overhead costs per item would represent only a minor additional charge, while, if added, here they would represent the bigger portion of the total cost. 

Additionally, the use of my own hourly labor rate for this project slightly inflated the cost, as my work took longer than that of an experienced professional. However, my labor rate was lower, reflecting my beginner skill level and slightly reduced quality. For a professional with more experience, the cost per item would be closer to $29.055.

Finally, I also excluded the drying time from the hourly labor rate, as this time could be (and it actually was) productively spent on other tasks, such as additional projects or, in my case, school assignments. So it wasn’t dead time of the project, as it could be reallocated and used for other things.

Conclusion

Overall, this project provided valuable hands-on experience with both plasma cutting and post-processing techniques, allowing me to explore how these methods affect material quality, especially with more intricate cuts. Working through each stage—from cutting and grinding to painting and cleaning—gave me a practical understanding of tool limitations and the impact of environmental factors like humidity on finishes. This experience reinforced the importance of patience and precision in manufacturing processes and gave me insights into cost analysis that will inform future projects, both in design and production. But, in particular, the thing i value the most is how, through this assignment, I got to first-handedly experience how trying to get a particular design on the wrong machine will impact the obtained results: Had I chosen a simpler inner design for the diamond, I’m pretty sure my task would have felt a little bit easier, and my post processing skills could have been better highlighted. Instead, the imperfections produced by requiring too high of a precision from the plasma cutting machine made me struggle more than what was needed.