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Aluminum is one of the most widely used metals for industrial, construction, and automotive manufacturing applications. But before you can use it, you have to process it. One of the basic metal processing that goes with aluminum is cutting. Aluminum cutting is possible through a number of processes, one of which is plasma cutting.
Aluminum is different from steel, so cutting methods and approaches are also different. In certain situations, aluminum cutting needs to be done with a specific method. In a nutshell, what makes cutting aluminum different from cutting steel is the technique and the gas mixture (1,2).
Plasma Cutting for Aluminum
Plasma cutters have been used to cut aluminum, but again you can’t cut aluminum the way you cut mild or stainless steel. Cutting any type of metal includes following the right techniques to ensure the quality of the cuts and your safety.
1. Prepare your workshop.
Basically, what you want to do is tidy up your work space. Do some cleaning and decluttering. Get rid of stuff that’s been lying around that you don’t need. The important part of this step is that you remove combustible materials away from your work area. Sparks landing on wood or paper or some flammable liquid can cause fire. When you’re wearing your helmet and focused on your task, you won’t realize that the corner in your workshop is burning.
Now, since you want to work safely, you had better check that machine. Check that its parts are intact. Any loose cables and hoses can derail your work or cause fires or explosions. Once you’ve checked your work environment and your equipment, it’s time to do the next step.
2. Wear safety gear.
It doesn’t matter what you’re cutting. You need to wear safety equipment if you’re using a plasma cutter. Personal protective equipment includes safety glasses, welding helmet, welding jacket, welding gloves, chaps, and boots. You may think these are a lot of stuff to wear. But the plasma arc and the cutting process produces a lot of radiation and sparks, which can cause injuries.
Eye protection, for instance, keeps harmful levels of radiation out. Ultraviolet radiation from the arc can burn your cornea and cause a painful condition called arc eye. OSHA’s recommendation is a shade 8 lens if you’re working below 300A.
Plasma cutting produces a lot of sparks that can fly anywhere and get trapped in your pockets or inside your shirt and burn your skin. Hence, wearing the right welding shirt, jacket, or apron is a necessity. You also need to wear gloves designed for welding as well as denim pants or welding chaps.
A lot of people who do welding and metal cutting disregard wearing hearing protection. Welding and plasma cutting are noisy affairs. The noise from plasma cutting machines ranges from 90 to 120 decibels. So wear earmuffs.
3. Ensure the right gas mixture.
The wrong gas leads to bad cuts with a lot of slag. This is a common problem with cutting aluminum using a plasma cutter. When cutting metals other than aluminum, a plasma cutter just needs regular air, which is compressed and filtered. For aluminum, a different gas mixture should be used to ensure clean cuts and reduce the need for cleanup afterwards.
There are different types of gas mixtures used for plasma cutting aluminum. Air and oxygen mixture isn’t recommended. What you need are any of the following combinations:
Nitrogen and carbon dioxide
Nitrogen and air
Argon and hydrogen
Because plasma cutting relies on an air source, make sure you hook up your air source. Ensure a snug connection between the machine and the air source.
4. The thickness of the aluminum sheet matters.
The right machine for the job depends on the thickness of the workpiece. While portable plasma cutters can slice through 1/4” or 1/2” sheets without any problem, heavy-duty machines are needed for thicker sheets. The thicker the metal, the bigger the arc necessary.
The speed and amperage also depend on the thickness of the material.
5. Create a sketch.
A smart way to work your way across a piece of aluminum, or any metal, is to sketch out a pattern beforehand. You can use a metal marker to draw the pattern on the workpiece. This way, you will avoid errors along the way and avoid the need to repeat your work and waste sheets of metal. All you need to do now is follow through the pattern you’ve made. This makes cutting easier and faster. Simply move the torch along the pattern or direction. When working with a template, use a drag tip. Do not drag the plasma cutter on the surface of the metal. Doing so will damage the machine.
6. Cut with the right speed.
One of the trickiest parts of plasma cutting for aluminum is that you have to find the right cutting speed. If you’re too slow, you can waste a lot of power. But if you’re too fast, you may not be able to penetrate the sheet and make successful cuts. Also, if your cutting speed is too fast, you’ll send sparks flying over the workpiece. In both cases, the quality of your cuts suffers.
You know when you’ve made correct cuts when the drag lines are at a 15-degree angle. If you’re going too fast or too slow, the angles will be different.
Cutting speeds should be anywhere from 1695mm/m to 4750mm/m depending on the material thickness and the arc voltage.
Conclusion
Plasma cutting aluminum shouldn’t be more difficult than plasma cutting mild steel or stainless steel. Any type of metal cutting entails some risks and precautions that you have to follow for safe and successful cutting. All you need to do is clean your workspace, wear your protective clothing, choose the right gas, create a sketch or work with a template, and cut with the right speed.
For a range if machines that are perfect for plasma cutting Aluminum visit our Plasma Cutter Reviews.
