You might have noticed a number of tools used by metal artists for precise cuts and metal fabrication. Definitely. I’m talking about the plasma cutter! Curious what it is and how it works?
As a mechanical engineer, I personally love it and I can’t wait to answer 15+ frequently asked questions about this tool.
What is Plasma?
Before I talk about plasma cutting or cutters, it is crucial first to know what exactly plasma is?
Plasma is the fourth state of matter (the other three are solid, gas, and liquid). [1]
When an ionized substance becomes highly electrically conductive, its behavior (plasma) is dominated by long-range electric and magnetic fields.
What is Plasma Cutting?
With plasma cutting, a jet of hot plasma is accelerated to cut through electrically conductive materials at higher temperatures than 20,000°C. Steel, stainless steel, aluminum, brass, and copper are typically cut by a plasma torch, though other conductive metals may also be cut.
What is a Plasma Cutter?
A plasma cutter is a tool that uses an electric arc through a gas that passes through a constricted opening. The extreme heat raises the temperature of this gas and converts it to the fourth state of matter (plasma).
Using this instrument, one can cut and manipulate the metals needed to make something. Metal fabrication shops, automotive repair refurbishments, industrial construction, salvage, and scrapping operations often use this tool.
As with other tools, you can cut metal to your liking, including stainless steel, aluminum, brass, steel, copper, as well as conductive materials with a plasma cutter.
How Does Plasma Cutter Work?
A pressurized gas like nitrogen, argon, or oxygen is sent through a small channel in this instrument. A negatively charged electrode is located in the center of this channel. The formation of a circuit occurs when you connect the negative electrode to the metal tip and apply power to it.
A powerful spark connects an electrode and a metal. The inert gas is heated until it can move into the fourth state through the channel. Metal becomes molten slag when its surface temperature reaches 30,000 degrees Fahrenheit and 20,000 feet per second.
This highly pressurized gas cuts through the metal, which is also directed around the perimeter of the cutting area to guard the cut.
Many of today’s better plasma cutters use a pilot arc between the electrode and the nozzle to ionize the gas and create plasma before the arc is transferred.
The other three methods used to ionize the gas are “touching the torch tip”, “use of a high-frequency starting circuit,” and CNC plasma cutting.
What is a CNC Plasma Cutter?
CNC plasma cutter allows you to arrange your shapes on the computer screen and cut automatically without touching the material.
Using different CNC software, piercing pauses and sizing can be programmed, acceleration and deceleration can be set at corners, and electric eye units don’t enable other functions.
What are Pilot Arc Plasma Cutters?
Pilot arc technology allows cutting without making contact with the metal. The quality of cutting is better, and the consumables last longer. Furthermore, it offers products that are both safe and affordable.
Compact plasma cutters use non-hazardous compressed air to cut stainless steel, alloy steel, mild steel, copper, and aluminum. You can set it up in one minute.
How to Set Up a Plasma Cutter?
- First, we decide where to set it up.
- You need to turn off the unit and plug it in.
- The external air compressor should be connected to the plasma cutter.
- Turn on the airflow. When the airline is perpendicular to the lever, turn it 90 degrees to the inline.
- Attach the ground clamp next to the area where you will be cutting the metal.
- Activate the machine by selecting the ON position on the switch behind it.
- Afterward, we will set the current thickness to 25 gauge metal sheets.
- After cutting the metal, shut down the machine.
PRECAUTIONARY TIP: Make sure that disconnect the ground clamp. 😉
The Plasma Arc Cutting Process
It is necessary to note that each of the variations follows the same basic principles and requires the same components. For example, the primary plasma arc cutting process may include the following phases:
- Main arc generation
- Pilot arc generation
- Localized heating and melting
- Material Ejection
- Arc movement
What are the Operational Types of Plasma Cutters?
There are many industries requiring plasma cutters, such as construction, auto, and locksmithing. The capabilities and design of this instrument have advanced along with technology. There are two types of plasma cutters: manual and mechanized.
1. Manual
Welding jobs can be done more conveniently with compact, versatile, and often portable tools. A manual cutter is generally handheld and used for cutting specific types of metals. Light-metal applications typically use these cutters to trim excess material, but they deliver high cutting amps.
2. Mechanized
On the other hand, large-scale jobs require the use of mechanical plasma cutters. They are more advanced and used in conjunction with cutting tables. To operate, these systems need an ample power supply, making them difficult to move around.
Mechanized cutters or manual cutters are best suited for material that needs to be cut based on its size, shape, and thickness.
Advantages and Disadvantages of Plasma Cutter
Let’s have a look at some merits and demerits of using the plasma cutter.
Advantages
Plasma cutters offer many advantages, given below:
- Can cut all the conductive materials of various thicknesses.
- Gives the most high-grade performance at the thickness of 50mm.
- Can cut up to 160mm.
- Comparatively cheap for medium thickness cuts.
- Precision can be achieved by cutting medium-thickness metals with a plasma cutter.
- CNC (Computer Numerically Controlled) option is also available for industrial-scale cutting.
- Can also cut under the water resulting in small HAZ (Heat Affected Zone) and less noise.
- Compared to oxy-fuel cutting, it has a smaller cutting kerf.
- Metals can be cut ten times faster with this method than with oxy-fuel.
- In addition to cutting aluminum and high-alloy steel, it can also cut materials of a wide range of thicknesses.
Disadvantages
The disadvantages of plasma cutting are as follows:
- Has a larger HAZ (Heat Affected Zone) than laser cutting when cutting in the air.
- Cutting quality is not as good compared to laser cutting.
- The tolerance is not as precise as laser cutting.
- In comparison to the flame cutter or water jet, it can’t cut very thick metals.
- There is a larger kerf on the plasma cutter than on the laser.
- It leaves a HAZ which a waterjet does not.
How Hot is a Plasma Cutter?
An impressive 25,000 degrees celsius is the temperature of a plasma cutter. To put this in perspective, it’s hotter than the sun’s surface, which sits at a comfortable 5505-degree celsius. 🤯
What Kind of Gas does a Plasma Cutter Use?
When plasma marks another subject, argon gas is used. When cutting thicker stainless steel or aluminum, it is often necessary to use an argon-hydrogen mixture. When cutting thinner stainless steel, some people use hydrogen, nitrogen, or methane and nitrogen.
FAQ’s
How Thick can a Plasma Cutter Cut?
The typical handheld plasma cutter can cut a maximum metal thickness of about 1 inch using cutting and gouging processes. In addition to compressed air and electricity, plasma typically needs both.
Who Makes the Best Plasma Cutter?
Here are some top brands:
- Hypertherm
- Miller
- Hobart
- Lotos
- Forney
- Eastwood
- Harbor Freight
- Lincoln Electric
- Everlast
- Amico Electric
These top brands in the market make your work easier and more comfortable for you. However, recently I wrote a detailed guide to the best plasma cutter brands, so please read it out.
How Much is a Plasma Cutter?
On average, plasma cutters can cost between $475 and $850. However, your usage scope, experience level, and the brand you choose decide the amount you need to pay for this tool.
Wind Up
Since 1980, plasma cutters have gained massive market share as these are most effective compared to the “metal against metal” technique. The problem with typical oxy-fuel cutting technology was inaccurate cuts along with production metal chips and inefficient edges.
Therefore, the plasma cutters industry kept improving from the large ones to CNC, where flexibility and diversity are under machine numerical control.
