Water Jet Cutter Design:

Knowing that simpler shapes have a better outcome on the water jet cutter, I decided to cut my initials for this project. The letters C and N are in different fonts, but I made sure that the fonts were simple enough in their edges to be cut.

Preparing the file for Protomax Layout:

To go from the .ai file to a file accepted by the water jet cutter, I used Protomax Layout. First, I clicked on “clean up” for the program to clean up the design. It found 4 duplicates and was able to simplify the design more. Then, after double-checking the dimensions, I generated the autopath. I chose the start point to be outside the design in the bottom left corner.

Protomax Make:

After preparing the file, I opened it in Protomax Make.

Water Jet Cutting:

The first time I tried cutting, the lab tech noticed that the sound the machine made was abnormal, and it was discovered that water got into the abrasive line. After it got repaired, I was able to finish my other cuts. It was suggested to me that after the the machine finishes the letter “C”, I should stop the cut to remove the letters that, after they got cut, were detached and could interfere with the rest of the cut. The results were two cleanly cut diamonds:

Post-Processing: Filing and Sanding

The edges of the diamonds were quite rough. I used a metal filer to take away the majority of the material on the edges. For the inside edges of the letters, I used sandpaper. To my surprise, sandpaper still did a great job at smoothing out the edges of the metal. The consequence, however, was that it left a lot of scratch marks on the surface of the metal.

Post-Processing: Spray Painting and Matte Clear Coat

I decided to use masking tape to paint the top and bottom half of the diamond two different colors. Diamond #1 had green on top and blue on the bottom, while Diamond #2 had the reverse. There were limited spray paint colors to choose from, so the green half was a mixture of two shades of green and a metallic copper color. The blue half was a mixture of blue, metallic copper, and gray-ish white. I spray painted the back of the diamonds with the same metallic copper paint. I sealed everything with a matte clear coat.

Issues: The first time I spray-painted, I misaligned the tape, which created a thin line that wasn’t covered and exposed the metal. I had to spray paint it again, but the layer of paint wasn’t equal to the rest of the painted areas. Also, I learned that if you accidentally touch the spray paint before it is dried and coat another layer to repair it, the deformity will still persist.

Cost Analysis:

Area of my diamond shape: 3″ x 2.5″ = 7.5″. 2 diamonds = 15″ in^2

A 12″x24″x 0.024″ cold rolled steel sheet= $20

15″ in^2 x ($20/288 “in ^2) = $1.04

Water jet cutter costs $25-30 per hour to operate.

My cut: 4 minutes x ($30/60 minutes) = $2.00

Labor = 4 hours x ($15/hr) = $60

Total cost = $1.04 (materials) + $2 (machinery) + $60 (labor) = $63.04

Compared to most diamonds on the market, this one is relatively cheap.

Conclusion:

It is interesting to compare laser cutting and water jet cutting. I prefer laser cutting, but it is cool to see how water jet cutting can cut something as strong as metal with just water and sand. Further, a metal piece would be more durable and more permanent than a wooden piece. When I first tried to do the homework, the water jet cutter broke down and needed to be prepared. It seems that there are more complex parts, and thus more prone to unreliability, comparing the water jet cutter to the laser cutter. Overall, it was cool to learn the file preparation for the water jet cutter and the post-processing techniques for metal.