Let’s Plasma Cut
Jim Correll, director Fab Lab ICC at Independence Community College, Independence Kansas
In a previous column, we discussed the carbon dioxide laser and how our mid-size lasers are the most popular machines and capability at the Lab. I don’t know if plasma cutting is second most popular or not, but it is near the top.
Plasma cutting is a means of cutting through sheet metal. Artists can hand-hold a plasma gun and cut flowers and all kinds of decorative designs out of shovels, bench backs or framed metal. You may have seen decorative cuts in sheet metal at craft shows. For the rest of us who can’t free-hand a rose, let alone using a plasm gun, here is the answer; mount the plasma gun on a gantry and use digital files to cut out the artwork. This is another way of saying you can create a file of what you want to cut out and let the computer and gantry do the intricate cutting, so you don’t have to have the skilled hands of an artist. Actually, for letters and shapes, the software that operates the plasma cutter has a text and shape tool built in so you can type up what you want to say and the machine will cut it out.
Normally, buying sheet metal is expensive but we have a special situation that allows us to have 1/8” thick sheet aluminum on hand, readily available to our members, for about $6.00 per square foot. This is about one-eighth of what you’d pay for new aluminum if it was even available in a small town like Independence. We have one of our local manufacturers to thank for that; VT Hackney. Hackney makes the beverage trucks we see on highways all over the United States. You know, the colorful trucks with the garage-like doors on the sides. These truck bodies are made of aluminum and Hackney buys giant coils of aluminum. For manufacturing, they have machines that unroll the coils and convert them into flat sheets. The very outer part of each coil can be scratched up and sometimes creased. While not suitable for their trucks, it is very suitable for most of our plasma cutting needs. They sell us sheets of what we call aluminum seconds at a price that’s slightly more than scrap but is allows us to resell to our members at an affordable price. Because it’s aluminum, two people can easily lift a sheet four-feet by eight-feet up onto the five-foot by ten-foot table. This combination of ease of use and affordability, along with light weight material is what makes plasma cutting so popular.
You don’t even have to be able to create an art file from scratch. There are many web sites with free or low-cost digital files available that can be uploaded to our machine. Just Google “Line Art: Plasma Cutting Examples” to get an idea of the plethora of designs available.
The technology of plasma cutting has been and is still a little hard to wrap my head around. Many of us, especially those with farm backgrounds, are familiar with the oxy-acetylene cutting torch. In that process, oxygen and acetylene gases are mixed to form a flame hot enough to cut through metal. I think there was something wrong with the tip I used on the farm growing up as I could never cut metal without it being a jagged, gloppy edged mess. I used a torch at Garden City Community College that worked correctly but was still faced with the problem of needing a nice steady, straight-line hand to make the cuts look good. Even with the better torch, getting a perfectly clean edge without globs of metal on the edges to be ground off was a challenge.
Plasma cutting uses an electrode, therefore the process only works with metallic, conductive materials, that forces hot gas through a small opening in the tip to do the cutting. In our case, we use compressed air as the gas. This makes for a much smoother, cleaner cut with less warping of the metal due to heat. Combined with the use of computer files for the cutting paths, makes plasma cutting easy for the novice to learn to use and we can show you how.
Plasma cutting is another example of how the digital world has been combined with the physical world to make processes like cutting metal easier and safer for the average person to learn. Fab Lab ICC is a member-based organization where individuals can belong for just $125 per year and learn to use our machines at a comfortable, enjoyable pace.
Jim Correll is the director of Fab Lab ICC at the Center for Innovation and Entrepreneurship on the campus of Independence Community College. He can be reached at (620) 252-5349, by email at email@example.com or Twitter @jimcorrellks. Archive columns and podcast at jimcorrell.com.