This week’s assignment was nominally about plasma cutting, but in reality, it was about post processing. Plasma cutting was actually a really easy process. Most of the work is in creating the file. Although the plasma cutter does require a bit more work to set up than the laser cutter, there’s not much more to it than setting the origin and hitting go.

After cutting my Texas shape out of aluminum with an feed rate of 70 inches per second, I got something that looked like Figure 1. The dross appeared to be worst in areas where the shape got more complicated—causing the head to spend more time in relatively the same area—and where the metal rested on the slats. This second reason was probably caused by the plasma cutter fusing some metal that had solidified on the slats during previous cuts to the aluminum.

After some quick work with a file, I got something that looked like Figure 2. Filing the edges proved somewhat difficult. The complexity of the Texas shape made it really hard to use a file, and after talking with Danny, I decided not to use the Dremel. This decision was both out of concern that the radius of the Dremel wheel would be to large to smooth out the curves I wanted it to and out of fear that I would severely alter the shape.

 

My post processing experience made me really happy that I had chosen to work with aluminum rather than steel. The file made quick work of the dross. The very thing that made filing off the dross so easy also made scratching the aluminum very easy.

The final step in my post processing was the sandblaster. I made sure that I sandblasted each face well to get rid of the scratches that I had left with the file. I also sandblasted the sides to help smooth them out, which worked better than I had expected. I decided not to spray-paint the shape because I liked the sandblasted aluminum look (Figure 3).

If I had more time, I would have lightly sanded the faces of my Texas cutouts to get rid of the deep scratches before polishing them. I would then have either used the fiber laser on the Epilogue laser cutter to etch a star where Houston would be or covered the Houston area with a star-shaped sticker and then sandblasted the rest of the shape before taking the sticker off to leave a star-shaped shiny area.