Hi everyone! In this project I used the plasma cutter to process a diamond-shaped metal piece designed by myself.

Background:

I have never used the plasma cutter before! I was very excited after the training. Before doing the project, I got myself familiar with the process of initiating the plasma cutter and creating the DXF, DGC file for plamsma cutting.

Part 1: Creating the Adobe Illustrator file

After downloading the diamonds from the course page, I decided to carve a lightning logo in the middle as it is one of my favorite patterns. I searched online for a satisfying pattern and traced the outline of it on Illustrator. After placing it on the diamond, the pattern looked like this:

Part 2: Plasma cutting

As mentioned before, I have gone through the process of plasma cutting serveral times for dry runs and test cuts. After converting the file to a DXF and DGC file, the pattern was ready to be cut. When I looked on the piece of metal sheet, I found that the place left for each diamond cut was not enough for cutting all 4 of them (I chose to cut 4 in case of damaging any of them in post-processing at the same time. Therefore, I have to cut each shape in separated places. This process largely increased my size-estimation skills.

 

Part 3: Angle grinding

The plasma cutter has created a lot of rough edges that would need relatively intensive post-processing. As the material I was using is steel, it was possible to be sticked on a magnetic fixing base to be angle ground. The metal piece was placed on the base and ground until there was no obvious bumps and grooves on the surface of the metal piece. The outcome was smooth and shiny. The result looked like this:

Part 4: Metal filing

There was an empty space in the middle of the diamond piece that was hollowed out. Therefore, some more post-processing was needed to smooth out the edges of the inside of the pattern that cannot be ground by the angle grinder because of the smaller scale. A metal file was used to clean these edges as shown in the following picture:

Part 5: Sanding

In order to make the pieces less likely to hurt people, I planned to use sandpaper to further smooth the edges. As the metal piece was already smooth before sanding, I decided to start with 220-grit sandpaper and work my way to 400 grits. This is a photo of the sanding process:

Part 6: Sand Blasting

I love the texture of sand blasting and that would be my final step of post-processing. After turning on the vacuum and putting the metal pieces in, I began to sand blast them with the sand gun. What turned out to be surprising is that sand blasting became the most time-consuming process. This might be caused by the low efficiency of the sand blasting gun. I had to put the outlet extremely close to the metal piece in order to create the texture. I also had to repeat the process again and again so that a uniform sand-blasting texture could be formed.

After that, I put on the six steps I used on a small paper and taped it to the back side of my diamond piece. It was finally done! These are pictures of the accomplished pieces.

Successes and Failures

Successes:

The plasma cut was pretty clean and none of the pattern was damaged by the inprecision of the plasma cutter.

There was no grooves or edges sticking out, the pieces were mostly smooth.

The sand-blasting added a pleasing texture which could minimize the effect of scratches on the surface.

Failures:

One small defect of the metal pieces is on the back of the pieces. There are 2 small pits on the edges of the pattern that couldn’t be ground or sanded.

The addition of the processing steps of the metal pieces could be more creative. Instead of a piece of paper attached to it, it could be a label through the hole in the middle, or even a piece of wood with etching on it.

Cost estimation:

Labor:

The 4 hours spent on the project: $15 * 4 = $60

Material:

About 50 square inches of metal: $0.02 * 50 = $1 (metal sheet price)

Rental of machinery:

Plasma cutter: $18/h * 1 = $18 (plasma cutter rental)

Angle grinder: $6.75/h * 1 = $6.75 (angle grinder rental)

Sand Blaster: $50/h * 1.5 = $75 (sand blaster rental)

Total cost: $60 + $1 + $18 + $6.75 + $75 = $160.75