Introduction
For the 4th homework assignment in ENGI 210, used a water jet cutter to cut a metal diamond design (2x) and then applied metal post processing and finishing techniques to refine its appearance and feel. Even though I have had some experience with the water jet cut, I followed the beginner level instructions because I was on a time crunch due to midterms and other assignments. In this project I cut two identical metal pieces, post processed them using three different methods.
The Process
Water Jet Cutting
I began by designing an SVG file in Inkscape that I would use to cut. I chose a K in the middle of the design as well as a gear to the right of it and a rice logo to the left of it. I then scheduled some time on fabman and transferred my design to ProtoMAX water jet software, taking all the necessary steps through the software to prepare the machine for cutting. Before starting, I ensured the metal sheet was properly secured with clamps, the water level was right, the machine was properly jogged, and there was enough abrasive.
Securing the metal sheet
ProtoMax Software Setup for our diamonds
WaterJet in Action
Once the setup was complete, I started the cutting process, which took 41 minutes since I combined my design with two others so that we could all complete this portion of the assignment faster. We paid close attention to water levels and how the machine was moving throughout the cut, unfortunately though the water level became too high and the abrasive built up. Thankfully though we were able to clean the abrasive and lower the water levels so that we could continue our cut. The final cuts were not as clean or precise as we would have wanted, but they were good enough to continue. 
WaterJet Cut Results
Post Processing
After cutting, I focused on three key post-processing steps to refine the metal pieces, sandblasting, spray painting, and clear coat application.
To remove any surface imperfections and rough edges, I used the sandblaster in the OEDK wetlab. Sandblasting helped create a smooth, matte finish by eliminating metal oxidation and sharp edges from the diamond.
After Sandblasting
Next, I applied a green spray paint to enhance the design and give it a nice looking finish. I used multiple thin layers to ensure even coverage and prevent paint buildup. I let the coat dry for about an hour before I moved to the next step.
Two metal diamonds hanging on the rack after spray painting
To protect the paint and prevent chipping or rust, I applied a clear coat spray as a final layer. This step added a sort of glossy finish while increasing durability against scratches and wear.
Two metal diamonds hanging on the rack after clear coating
Final Product
The final metal diamond pieces had a clean, smooth surface, with the green spray paint and clear coat providing a fairly professional appearance.
Final Product
Reflection
This project helped me understand the basics of water jet cutting, post-processing, and finishing techniques. If I were to repeat this project, I would choose a simpler design that the water jet could more easily handle, improve my sandblasting technique to achieve an smoother surface, experiment with different paint finishes and improve my spray painting avoid uneven coating.
Materials Used
1×1 foot Metal Sheet ($10)
Rented WaterJet Cutting Time (16 minutes) ($4.00)
Rented Sand Blasting Time (20 minutes) ($2.00)
Spray Paint (1 Can) ($4.00)
Clear Coat (1 Can) ($4.00)
Total ($24.00)
