For our sixth assignment, we were challenged to use the plasma cutter and post-processing techniques to make an object. I had never used the plasma cutter before this class, so I was excited to experiment with this new tool.

Stage 1- Designing the object

The first step in my process was to choose the design for my object, given the diamond shaped template necessary for the basis of my design. I really like elephants, so I thought I could cut out a walking elephant and add footsteps to make it seem as if it had walked onto the template. I did this by finding an outline of an elephant online and using the pen tool on illustrator to trace the shape.

I used the basic shapes tool to make the footsteps with ellipses. I placed both the elephant and the footsteps onto the template and converted the file into a dxf format suitable for the plasma cutter. I then cut the drawing onto an aluminum sheet using the plasma cutter.

Stage 2- Using the plasma cutter

The video above shows the plasma cutter cutting my piece. My first cut didn’t turn out very well. The footsteps were almost imperceptible, the material wasn’t cut through all the way, and I had too much dross.

I recut the material again with different settings (voltage of 80 instead of 120) and got much better results, primarily because the material was cut through all the way. However, the footsteps were not cut well (just as in the previous cut). I figured that the holes were too small. I changed my Illustrator drawing to make the footsteps slightly larger. The third and final cut came out much better. I had some dross, but the cut seemed pretty clean overall.

Stage 3- Post-processing

Now that I had my two pieces adequately cut, I moved onto post-processing them. My first goal was to remove the dross. Removing the dross from the exterior edges, top, and bottom was easy because they were easily accessible. I first attempted to use the sand belt, but it wasn’t as effective as I would’ve hoped. I used the angle grinder, which worked much better because it was able to quickly remove lots of material. Removing the dross from the inside was more challenging because I needed a tool that could get into the small cracks. I considered using a file, but decided otherwise because most of the files were too large and I realized it would’ve taken me a significant amount of time to be able to remove all the excess material. Luckily, Adulfo recommended I use a dremel with a metal bit. Although it was hard to make both plasma cut pieces exactly identical after using the dremel, the tool was an effective way to remove the dross.

Once all the dross was removed, I moved on to sand blasting the piece. I chose to do this because I wanted to paint my piece and I wanted to ensure I had an even surface before doing so.

Now that I had an even surface, I spray painted the pieces in a vibrant orange color. I struggled quite a bit with the spray painting because in my first attempt, immediately after applying the paint and leaving the piece out to dry, it started to rain spontaneously. The rain ruined the paint I had just applied because it was no longer sticking well to the material. I had to sandblast the piece again and reapply the paint. In this second attempt, however, I applied too much paint and tried to move the piece from the floor to the table. Through that movement, I moved the piece and the paint smeared. I had to sandblast a third time and spray paint again.  

My third attempt went fairly well. I was able to successfully paint the front for both pieces and the back of one of them. The paint on the back of the other piece smeared a little on the edge. Since the smear was so small, I sanded it down using sand paper and lightly painted over that area.

Stage 4- Done!

Overall, I would say I’m satisfied with my piece. However, I would like to become better at spray painting to make the piece surface smoother and to limit the number of mistakes during painting. I would also like to experiment with different post-processing methods.

Cost Estimate

Labor

• I worked for 4.5 hours, assuming a rate of $15/hour = $90

Materials

• Aluminum: 36 in. x 36 in. sheet sold by Home Depot for $31.98. I used approximately ⅓ of that amount, so $31.98/3= $10.66
• Paint: One can of spray paint sold by Home Depot for $4.27. I used approximately half a can, so $4.27/2= $2.14

Machining

• To use a laser cutter at a fabrication lab outside of Rice, I would have to pay at least $50 (the price of the “Tinkerer”, the cheapest membership which includes full access to tools at TXRX Labs)

Total cost: $90 + $10.66 + $2.14 + $50 = $152.8