It was very cool to get to cut metal in this last project. These are the pieces I did!

If you want to know how to make your own waterjet cut diamond, read the steps below for how I did mine!

How to make your own metal diamond:

1. First, I downloaded the diamond shape to Adobe Illustrator. I decided that I wanted to cut an octopus in the inside of it, but when looking at the Noun Project options, I was not really convinced. Also, one that I liked had too many lines which would not work with the waterjet. Thus, I decided to draw my own! It wasn’t super straight forward since I did the drawing by parts and then had to join them, remove the inside, etc. But I managed! This is how it looked in the eld:
   

   Adobe Illustrator file for the piece

2.  After that, I used the waterjet to cut my piece. I followed the steps on the instructions. During the process, I had to measure the metal, for which I used calipers; the piece was 0.06 in thick. These are the two files from the first and second programs (ProtoMAX LAYOUT and ProtoMAX MAKE respectively) needed for modifying the Adobe Illustrator file as well as for cutting the piece with the waterjet:
   

   Program 1 (ProtoMAX LAYOUT) used to modify my Adobe Illustrator file for waterjet cutting

   

   Program 2 (ProtoMAX MAKE) used after the first program to cut the piece

   

   Using the waterjet

3. After cutting two pieces with the waterjet, I checked and saw that they were similar pieces, so I did not cut any more. Here you can check for yourself:
   

   Waterjet metal pieces

4. After cutting, I started post processing the two pieces.
   1. First, I filed the two more pointy corners from the metal pieces and started filing the inside of the octopus. I wanted to get smoothen some very spiky sides because I did not want whoever picked up the diamonds to get hurt by them (when I took the metal for waterjet cutting, I touched more than one deep corners from other people’s projects and it wasn’t nice!)
   2. However, since the sandblaster was available at that moment, I went to sandblast my piece without having finished filing. This is how my piece looked before and after sandblasting:
      

      Non-sandblasted side of the piece (I had already started sandblasting the other side and realized that I had not taken a picture!)

      

      Pieces after sandblasting

   3. This was not the best idea though, because after sandblasting, I then went to finish filing the inside of the octopus but I scratched it a bit.
      

      A little scratch on the octopus after filing

   4. So, then I decided to sandblast again a little:
      

      After sandblasting again

5. After post-processing, I printed some stickers with the vinyl cutter
   1. I first made an Adobe Illustrator file that looked this way:
      

      File for vinyl cutting

   2. I had to flip the file horizontally and print another set of stickers for the other side of the diamonds since these are mirror images of the original octopus. These are some stickers printed:
      

      Stickers!

   3. I then pasted the inside octopus on one of the sides and the negative of it with a diamond outline on the other side. On the side with the octopus in the middle, I also added strips of the sticker vinyl that I cut myself on the outline of the diamond. I decided to flip the design for one side after printing the stickers, so I did this instead of printing more stickers as I thought that it was not necessary for just the sides.
      

      Side with the negative of the octopus and diamond outline

      

      Side with the octopus sticker and vinyl on the sides

6. With the stickers in place, I then spray painted the pieces, waiting for each side to dry in between:
   

   Spray painted the front in blue

   

   Spray painted the second side with red

7. After painting, and once dry, I removed the stickers.
8. I noticed that there has been some small ‘leaks’ of paint through the stickers and tape in some spots.
   

   The back side had more spots

   So, I decided to try to clean these up. I was first given by a TA some small ethanol wipes, but then I run out of these, but I was told that the there were ethanol bottles, and so I used some swabs to carefully remove the extra paint. I did not manage to remove everything, but it looked a lot better.

9. Once this was finished, I sprayed a clear coat of gloss enamel to the pieces, waiting for each side to dry.
10. And, my piece was finished!

Troubles and Improvements:

• It was not super easy to figure out how to use the waterjet at first. The first time we tried, I was with Raeedah and even someone else that wanted to learn how to use the machine was there but I was having trouble managing to enter an origin such that the waterjet would start cutting from the middle of the shape. With help, we managed to make it work, but when I wanted to take the piece out, it had not cut through! We first thought that it had been the water level being a bit too high but later Raeedah told that it was probable that we had taken aluminum instead of steel. Since there was no more metal left, I forgot to check!!
• I did not realize that the sticker had to be mirrored for one side until after printing. That plus that some stickers were not good, I ended up printing 7 stickers in total, which are more than I needed…
• I also realized when printing the stickers that because I had used the brush in Adobe Illustrator, the lines for the octopus were double lines as seen below. This was not an issue but could be changed in the future in the case that the boundaries are important since this removes an extra thin layer of sticker.

• And, as mentioned above, the paint leaked between the stickers a little, so next time I would try to press them more firmly against the piece or try to look for another solution.

How much would this cost?

Labor time: 456 min

• If the wage is $14/hour (chose this value), then the labor cost would be:
  • $14/60 min * 456 min = $106.4 
• However, this time includes learning time, which means that for a normal piece it is an overestimate.

Machine time:

• I used the electricity cost/kWh calculated for the sewing project again ($0.1638695652 per kWh) (https://engi210.blogs.rice.edu/2023/01/22/paulas-apron/)
• Waterjet: 9 min 22 s (counted the second diamond time and multiplied by 2)
  • Since there are a lot of factors when calculating the cost of waterjets, I only used power to get an estimate. However, operating pressure, for the same power, also affects electricity cost. I also did not know which type of waterjet was used, so I used a middle value of about 72.5 horsepower or 54063.24 W [1].
  • Thus, using the electricity calculator [2]: 8.44 kWh which equals $1.38 
  • Compared to other machines, this seems like a lot, so in the future I would want to look into the type of waterjet used as compared to the types to which these powers correspond.
• Sandblaster: About 17 min
  • While I am not sure how the sandblaster at the OEDK, air compressors consume between 2 and 28 horsepower, so the middle value, 15 hp is 11185.5 Watts [3].
  • Using the electricity cost calculator [2]: 0.48 kWh which equals $0.08 
• Vinyl cutter: estimated about 2 min 34 s (about 22 s estimated for one sticker and cut out 7 stickers in total)
  • I did not consider this into the electricity cost since I believe that the time and the electricity consumption make the addition of cost very low.

Raw materials:

• Cut out two diamonds
• I believe that the material used was steel, but I am not sure the type. Stainless steel 0.06 in thick and 24 in x 24 in costs $154.66 [4].
  • The material used was a lot less. I did not have the diamonds in front of me for calculating the material used, but I estimate that I used at most, 5 in*3.5 in* 2 if considering the rectangular area around the diamonds. Thus, this would be about 35 in^2, so:
    • $154.66/(24*24 in^2) * 35 in^2 = $9.397743056 
• I did not consider the water or sand used in the waterjet.

TOTAL COST: $106.4 + $1.38 + $0.08 + $9.397743056 = $117.2577431 which is about $117

References

[1] https://www.aquajetservices.com/a-technical-guide-to-waterjet-cutting/comparison-between-waterjet-configurations/#:~:text=In%20waterjets%2C%20pump%20pressure%20ratings,drive%20pumps%20and%20intensifier%20pumps.

[2] https://www.calculator.net/electricity-calculator.html?appliance=&power=54063.24&powerunit=W&capacity=100&usage=9.366666666666666&usageunit=mpd&price=0.1638695652&x=67&y=26

[3] https://www.cycloneblasters.com/documentation/sandblasting-air-consumption/

[4] https://www.mscdirect.com/product/details/32004533