Plasma Cutting Aluminum

Plasma cutting is a process that uses a high-velocity stream of ionized gas to cut through conductive materials. Plasma cutting is commonly used to cut through metals such as stainless steel, aluminum, and copper.

Can a Plasma cutter cut Aluminum?

Aluminum is a popular material to plasma cut because it is strong yet lightweight. When cutting aluminum with a plasma cutter, it is important to use the correct settings and techniques to avoid damage to the material.

Check out this article on How Plasma Cutting works?

Yes, plasma cutting aluminum is possible using a plasma cutter or CNC plasma cutting machine. But there are some things to keep in mind when using this method.

Plasma Cutting Aluminum
Image Courtesy: Machitech

First, the thickness of the aluminum will affect the speed and quality of the cut. Higher the aluminum thickness, lower the cut quality and finish.

Second, it’s important to use the correct settings on your plasma cutter to avoid damaging the material.

Third, using the right plasma gas is equally important. Using nitrogen or mixture of nitrogen + Hydrogen gives best cutting surface finish. Air is cheap but quality is compromised.

Here are a few things to keep in mind when plasma cutting aluminum:

  1. The torch needs to be set up correctly. The correct tip size, gas mixture, and flow rate should be used.
  2. Use a lower air pressure when cutting thin aluminum. This will help to prevent the aluminum from being blown away by the plasma jet.
  3. Use a sharp drag tip when cutting aluminum. This will help to prevent the formation of dross on the cut edge.

How plasma cutting works?

Plasma cutting is a process in which electrically conductive materials are cut through by means of an accelerated jet of hot plasma.

Typical materials that can be cut with a plasma torch are steel, stainless steel, aluminum, brass and copper, as well as other conductive metals.

Plasma cutting is widely used in manufacturing operations, automotive repair and restoration, industrial construction, and salvage and scrapping operations.

Due to the high speed and precision of the cuts at low cost, plasma cutting is widely used from large industrial CNC applications to small hobby companies where the materials are subsequently used for welding. 

Plasma cutting – Conductive gas with a temperature of up to 30,000°C makes plasma cutters so special.

Plasma Cutting Aluminum

There are three main factors to consider when plasma cutting aluminum:

  1. Torch tip size,
  2. Cutting speed, and
  3. Power level.

For a plasma cutter or CNC Plasma cutting machine, torch tip size is determined by the thickness of the material being cut. Cutting speed is measured in inches per minute (ipm). Power level is measured in amps.

The correct settings and techniques for plasma cutting aluminum will vary depending on the specific application. Higher amperage is required to cut thicker material.

Plasma Cutting Gases

Plasma cutting is a process that uses a high-velocity stream of ionized gas to cut through electrically conductive materials.

The gas, typically either air or an inert gas such as argon or nitrogen, is passed through an electrical arc to create the plasma.

The plasma cutting process can be used to cut through a variety of materials, including metals, alloys, and thermoplastics.

In order to cut through these materials, different types of gases are used. The most common types of gases used in plasma cutting are:

  1. Air,
  2. Nitrogen (N2),
  3. Mixture of hydrogen (H) & argon (Ar): H35 (contains 35% H & 65% Ar), and
  4. Oxygen (O2),
  5. Mixture of hydrogen & nitrogen (Usually 5%H and 95% N2).

Nitrogen is costly but provides best aluminum cut quality using Plasma cutting. Mixture of Nitrogen and hydrogen also provides good gas cut quality.

Effect of Gas on Plasma cut Quality (ref:Hypertherm)

Each type of gas has its own advantages and disadvantages. Air is the most common type of gas used in plasma cutting because it is readily available and relatively inexpensive.

However, air can cause the formation of oxides on the cut surface, hence gas cut quality is not very good. Air can cause the plasma torch to overheat, which can shorten the life of the torch.

Nitrogen is another common plasma cutting gas. It is less likely to cause the torch to overheat than air, but it is more expensive. Nitrogen can also provide a better quality cut on thicker materials.

Oxygen is the third most common plasma cutting gas. It produces a very hot flame that can cut through thick materials quickly. However, oxygen can also cause the metal to become brittle and break apart easily.

Can you cut Aluminum with a plasma cutter?

Yes, a plasma cutter can be used to cut aluminum. Plasma cutting is a process that uses a high-velocity stream of ionized gas (plasma) to cut through electrically conductive materials, such as aluminum.

The plasma is created by passing an electrical current through a gas, such as compressed air, which ionizes the gas and creates the plasma stream.

This stream is then directed through a small nozzle and onto the workpiece, where it cuts through the material.

Plasma cutting is a fast and efficient way to cut aluminum, and it can produce accurate cuts with minimal heat-affected zone.

However, it is important to use the correct cutting parameters and nozzle size to ensure a clean and precise cut.

It is also important to note that aluminum is a soft metal and the cutting edge might need to be deburred.

What is the best gas for Plasma cutting aluminum?

The best gas for plasma cutting aluminum is compressed air. Compressed air is commonly used as the plasma cutting gas because it is readily available, relatively inexpensive, and produces a good-quality cut.

Plasma Gas (Shielding Gas)AdvantagesDisadvantages
Compressed Air (Air)Cheap, high cutting speed, good quality cut.rougher finish and may not be at a perfect 90 degree angle.
Nitrogen (Air)Economicalrougher finish and may not be at a perfect 90 degree angle.
Nitrogen (Nitrogen)Economicalrougher finish and may not be at a perfect 90 degree angle.
Nitrogen (CO2)Slightly faster & better cut qualityrougher finish and may not be at a perfect 90 degree angle.
65% Ar + 35% H2 (Nitrogen)Wider cutting capacity, Smooth cut edges.Costly & limited supply.

Other gases such as Nitrogen, Oxygen, and Inert gas (Argon, Helium) can also be used for plasma cutting aluminum, but these gases are more expensive and require specialized equipment.

In general, compressed air is considered the most practical and cost-effective gas for plasma cutting aluminum.

Plasma Cutting Advantages

  • One of the most economical cutting processes in the steel sector up to approx. 35 max. 40 mm thickness.
  • Plasma cutting is one of the fastest thermal cutting processes.
  • Achieves a high cutting quality (not “high” in comparison and in the sense of laser cutting or waterjet cutting, although state-of-the-art quality plasma torches achieve certain accuracy overlaps with the laser!)
  • Less thermal influence than with oxyfuel cutting.
  • Unmanned cutting partly possible, good automation.
  • Cuts all electrically conductive metals.
  • Cutting speeds depending on the electrical conductivity of the material and not on its hardness.
  • Relatively little post-processing (usually only a little burr or slag adhesion to remove!).
  • Smaller inner contours and holes than with oxy-fuel cutting can be cut
  • Cutting thicknesses of up to 160 mm are possible and often used when cutting stainless steel.
  • Special cutting technologies can be used: dry cuts and underwater cuts (Attention: In underwater plasma cutting, the cutting properties, qualities and cutting parameters change).
  • Special applications available: machine and hand-held torches; Sheet, coil and pipe applications.
  • Complete CAD/CAM controlled production with continuous database is possible.
  • Robust process that makes no special demands on the environment in contrast to the laser.
  • Also cuts rusty steel and oily surfaces, even painted surfaces, if the paint does not exceed a certain thickness.
  • Fast grooving in thicknesses up to 50 mm material thickness is no problem and takes only a few seconds. Maximum piercing into solid material is possible with special high-performance plasma torches up to approx. 120 mm in air and up to approx. 80 mm underwater.
  • Investment costs are lower than laser cutting.
  • Probably the most important advantage: It is the most economical separation process for steel up to a maximum thickness of 40 mm. Above 40 mm thickness, the oxy-fuel burner is in front. Below approx. 10/12 mm, the fiber laser is more economical. The areas are constantly in motion depending on new developments and can therefore shift in all directions.

Plasma cutting disadvantages

  • Power consumption relatively high.
  • Exposure to dust and ozone, a filter is required, mandatory!
  • Internal contours often not precise enough due to the trailing effect of the massive gas.
  • Hardening of the plasma section in the edge zones (larger for underwater sections)!
  • Post-processing may be required depending on requirements (depending on material and burner type).
  • Investment is higher than for oxy-fuel cutting systems.
  • The high cutting quality of laser cutting systems cannot be achieved – beware, from false expectations of the end user – plasma is not a laser, does not reach its accuracy class for all cutting contours.
  • Special technical gases must be stored in order to achieve optimum cutting results.
  • The cutting quality is not constant – depends on many parameters/ wear/cutting time/ piercing cycles, etc.
  • Depending on the burner type/setting/condition/ experience, high wear parts costs are possible if the system is not operated optimally! Further qualification of the operators and sensible areas of application can be used to counteract this.

Material Welding is run by highly experienced welding engineers, welding trainers & ASNT NDT Level III bloggers. We strive to provide most accurate and practical knowledge in welding, metallurgy, NDT and Engineering domains.