This week I made 2 metal diamonds. This project had a few unexpected events but overall I think I learned a lot of new skills.
First, I cut 2 diamonds out of the steel sheet using a ProtoMAX Waterjet. This involved creating a design for the diamond with adobe illustrator. I decided to cut out the shape of my home state, Maryland by looking up an image of an outline of the state and vectorizing it with inkscape. I then made a 5x3in diamond on Onshape and exported the dxf file to inkscape and centered the diamond and the outline on top of each other shown in Figure 1.
Figure 1. Resulting diamond dxf file
Once I created my file, I went to the ProtoMAX Waterjet and imported my vector file into the ProtoMAX MAKE software. I made sure to measure the thickness of the steel I was using to ensure I input all the right parameters into the software. I got a measurement of 0.07 inches and I selected a thickness of 0.08 in the ProtoMAX to ensure that the cutter would get through the material. I selected a tool offset of 0.05 in since the shape of Maryland has lots of smaller features. To set up the waterjet cutter, I followed the instructions, including filling the water up to a specific level and adjusting nozzle height. By following the instructions for the machine I was able to successfully cut out two diamonds in one cut.
Figure 2. Measuring steel thickness
Figure 3. ProtoMAX MAKE software with parameters
Figure 4. Waterjet cut steel pieces
After I cut out the diamonds I sandblasted them to make the surface more uniform and better suited for powder coating. Sandblasting resulted in an almost glittery finish on the steel. A before and after is shown in Figure 5.
Figure 5. Before and after sandblasting
Figure 6. Both diamonds after sandblasting
After sandblasting, I filed the edges of the diamond to smooth them out. The file I used is shown in Figure 7
Figure 7. Both diamonds after filing.
After filing the diamonds, powder coated them with a brown coating. I set up the powder coating gun as the instructions outlined and successfully powder coated my metal pieces. However, someone else wanted to use the rack right after me(since there is only one rack available), which made me wait to put my pieces in the oven for over 30 minutes. While waiting I had to hold my pieces by the paper clip and wait. This jostling and lack of oven time led to imperfections in the powder coat. The fact that the other student was using a different color also negatively impacted my powder coat. Causing some specs of yellow to end up on my pieces. If powder coating, I would not recommend waiting for someone else, just make them wait the 20 min needed for curing and give them the rack afterwards.
After powder coating, we placed our pieces into the oven at 400 degrees and waited 20 min. We then took the diamonds outside to cool. The resulting powder coat was relatively uniform but there are clear locations of under spray and over spray as well as small gaps in the coating.
Figure 8. Powder coating set up.
Figure 9. Powder coated diamonds
In an effort to give the diamonds a cleaner look I used the vinyl cutter to create a sticker that looks like the Maryland flag. The goal of the sticker was to cover up imperfections and maintain the Maryland theme with a stylistic touch. I imported an image of the Maryland flag on to the vinyl cutter and etched the sticker out of black vinyl. To remove the sticker, I did not use transfer paper, since I was having a lot of difficulty transferring with this method. Instead I made my vinyl cuts near locations where it had been cut in the past and used a box cutter to pull up the vinyl by hand. I then placed both diamonds on a respective flag and carefully cut out the center outline. Furthermore I hand peeled portions of the sticker to ensure the sticker had the same pattern as the Maryland flag.
Figure 10. Maryland flag vectorized image
Figure 11. Hand peeled vinyl
Figure 12. Finished Diamonds
In conclusion, this project took me much longer than expected. I made errors in multiple portions of the process resulting in a product that could definitely be improved in future iterations. However, I am overall proud of the final product. I think the imperfections are down played by the flag pattern and I like how thematically cohesive the overall design is. I learned a lot through this project and I am excited to apply the skills I have acquired in future projects.
In total, my two diamonds costed, $154.77 to make. I think the main source of expenses was the labor costs, mostly designing components and putting them together. I think more experience would allow me to go through steps faster with fewer mistakes, likely decreasing costs by at least 30%.
| Cost Type | Cost | Price | Source | Quantity | Total |
| Materials | 1/16 in thick steel sheet | $6.50 / sheet | Amazon.com | 1 sheet | $6.50 |
| Vinyl | $0.62 / Foot | Amazon.com | 2 ft | $1.24 | |
| Metal File | $5.66 / set | Amazon.com | 1 set | $5.66 | |
| Powder coat | $2.25 / oz | Amazon.com | ~3 oz | $ 6.75 | |
| Labor | Waterjet cutter Operator | $17/ hr | ziprecuiter.com | 1 hour | $17 |
| Vinyl cutter Operator | $18/ hr | ziprecuiter.com | 2 hours | $36 | |
| Sandblaster operator | $18/ hr | ziprecuiter.com | 0.5 hour | $18 | |
| R & D(decal and cut out design) | $17/hr | ziprecuiter.com | 1.5 hour of designing and assembling | $42.5 | |
| Overhead | Waterjet time | $20/hr | wardjet | 1 | $20 |
| Sandblaster time | $45/ hr | Homeadvisor .com | 0.5 | $0.5 | |
| Misc. | Waste and Scrap | $0.62 (from vinyl waste all other materials were recycled) | Amazon.com | 1 | $0.62 |
| Total | $154.77 |
Figure 13. Cleaned Workspace
Figure 14. Cleaned Work Space
Figure 15. Cleaned workspace
