For this project, I worked alone to produce two metal diamonds with a design with using the water-jet cutter and post-processing techniques. This was the first time working with the water jet cutter, so it was a new experience in creating a part with the machine, and much more work was exerted for the post-processing aspect of fabrication.

PHASE 1: Designing and Cutting out the diamond

To begin the project, I used Adobe Illustrator to design a part to cut out on the water jet cutter. Using the diamond template provided for the class, I added the design into the middle of the diamond. This was the outline of the Circuit des 24 Heures du Mans, the setting of the famous 24 Hours of Le Mans endurance motor race. I thought that the circuit outline would make a cool shape to cut out as it is recognizable with some complex aspects. This design was imported as a vector into the diamond design, and the shape builder tool was used to create the piece.

With the design ready, it was time to use the water jet cutter. Following the process to operate the water jet, the first cut of the design went well, but the second had to be done another day. The part was cut on a silver sheet.

However, issues would be run into when attempting to cut the second piece. When the same procedure was done again, the auto path generated 2 paths to cut the piece. This was noted as an issue because when the dry run was done, the water jet cutter would be going over the part twice, potentially damaging the bed if not stopped. Multiple things were done to correct the issue, including consulting Lab Assistants and Dr. Wettergreen. One potential solution that would be found was the reworking of the shape, as it was not properly joined, which could hav resulted in multiple lines influencing the path. However, it would turn out to be an offsetting problem, as setting an offset created the second path.

To solve the issue, the tool offset was set to zero to create a single cutting cycle for the part.

With that, the two parts were cut.

PHASE 2: Filing

To begin the post processing aspect of the project, the edges of the parts would be filed. Something noted when the part was cut from the water jet cutter, the edges would be left rough and extruded opposite from the face cut. As such using the file would smooth out those edges, these including the ones around the design and the diamond piece as a whole.

After the filing, the edges were much smoother.

 

PHASE 3: Sandblasting

After filing, I went to sandblast the parts. I saw sandblasting as something that could clean off the silver layer of the part. I compared the looks between the sandblasted and un-sandblasted pieces, and noticed a pretty big difference between them. The look and texture of the sandblasting was much more desirable.

As such, the two parts were sandblasted as the second part of the post processing. There was a notable challenge of keeping an even sandblast, and touching a sandblasted part without gloves was not ideal to keep the coating stable.

PHASE 4: Painting disaster

After sandblasting, the texture of the sandblasted parts gave me some sort of inspiration for the painting of the piece. Since the design cutout was the circuit for the 24 Hours of Le Mans, to keep the theme going, I got the idea to paint the top and bottom edges with the colors of the livery of the Audi R8, which won the race in 2000. The idea mainly stemmed from the sandblasted metal resembling the silver of the livery.

To paint the idea, the top corner was going to be red, and the bottom corner some sort of black, with the middle being just the sandblasted metal finish. Ideally, I would have attempted to powder coat, but I had some reservations throughout the project due to my anxiety with working with high levels of electricity. So in the end, I opted to spray paint.

The middle area was covered in the masking tape, and the paint was applied. The red paint applied well, but the black paint was much more runny. To avoid having to use that can then, I decided that the parts would both be red, but unfortunately the damage was done already. The black paint ran under the tape onto parts of the piece I did not want painted, and no sandblasting or filing could remove it. At that point, it was decided to paint the entire part red.

 

PHASE 5: Reflection and cost estimate

Entering this project, I thought that it would be pretty challenging to post-process the part than going to cut it. While some challenges were faced when cutting with the water jet cutter, the step was very straight-forward. However, the real issues would arise with the post-processing. In the end, a lot of these issues resulted in a part that I am sadly not proud of the final results for due to my compounding mistakes. Of course, I am proud of being able to learn and apply skills related to water jet cutting and post processing, but just wish the part could have been finished better and to plan.

If I were to repeat this project, I would certainly allocate a lot more time to planning and executing the post-processing of the pieces. A lot of issues could have been avoiding with planning, and more iterations of post processing could have been done with more time.

The following is an estimated cost of the two diamond pieces:

• 12′ x 12′ steel sheet (Home Depot) = $10.47
• Overhead/Service cost for water jet cutter (TechniWaterjet): $37.50 x 2 hours = $75
• Labor: $18/hr (national average for a water jet cutting operator by ZipRecruiter) x 2 hours = $36
• Labor: $19.74/hr (national average for a spray painter by Payscale) x 3 hours = $59.22
• Spray paint and tape: Negligible.

The estimated cost for the two metal diamond pieces is $180.69. To reduce the cost of the pieces, labor time could have been reduced my mitigating mistakes around the post processing of the pieces.