CNC Plasma Cutting：The Basic Simply Explained

There are several techniques that can be used to cut sheet metal, including CNC milling, laser cutting, and CNC plasma cutting. CNC milling machines use a cutter head to make the cut, while plasma cutters use a high-temperature plasma torch to blast the metal. The process may seem comparable to laser cutting, as they are both non-contact. However, plasma operates at higher temperatures, so it can cut thicker materials.

CNC plasma cutters also use the G-code as a cutting command, and when we say cut, we mean it. Plasma cutters have too much cutting power to carve beautiful patterns in metal; that job should be left to CNC milling machines. Plasma cutting is primarily used to cut large format sheet metal used for welding. Plasma cutting is a good choice for those who have frequent metal cutting needs because it is relatively easy to operate once set up. The limiting factors for CNC plasma cutters, on the other hand, are usually safety and the shop space required for the equipment.

So if you're in need of some heavy-duty metal cutting, keep reading this article to learn how plasma cutting works and what it takes to make cuts in your own shop.

1.Working Principle of CNC Plasma Cutting Machine

2. Precautions for CNC Plasma Cutting Machines

3. Materials and Gases for CNC Plasma Cutting Machines

4. Workspace and safety of CNC plasma cutting machines

5. Plasma Cutting Machine Application Industries

1.Working Principle of CNC Plasma Cutting Machine

The impressive cutting power of a plasma cutter comes from its ability to harness and direct the fourth state of matter, plasma. With the exception of the surface of the sun or a lightning strike, people don't often see plasma in their daily work. This is because it is very high energy and is formed when a gas is heated to conduct electricity.

The principle of how a plasma cutter works is actually very simple. A pressurized gas is forced through a copper nozzle. The nozzle is part of a carefully designed circuit that carries the high current needed for ionization. As the gas leaves the nozzle, it must pass through an electric arc. The arc is so powerful that it ionizes the gas and converts it into plasma. Air pressure from the nozzle forces the plasma to move downward to the surface of the sheet metal. The plasma melts the metal and pushes the molten material away. This means that plasma cutters do not cut as cleanly as milling or laser cutting.

2. Precautions for CNC Plasma Cutting Machines

CNC plasma cutters vary greatly in size, price and features. There are both large machines that cut huge industrial parts and 4-foot by 4-foot machines that can fit into almost any shop. Overall, these machines are generally accurate, but not as accurate as a milling machine. The strong suit of plasma cutters is speed, cutting metal at speeds of up to 500 inches per minute.

Of course, these specifications reflect commercial equipment. Keep in mind, though, that a cutter's capabilities depend on the amount of power it can produce. The amperage of the arc largely determines the thickness of the sheet metal as well as the power of the compressor. A higher amperage produces a stronger plasma arc, which means you can cut thicker sheets of metal. The type of metal that can be cut depends on the type of gas used to generate the plasma.

3. Materials and Gases for CNC Plasma Cutting Machines

It is important to note that sheet metal becomes part of the circuit that generates the plasma, so only conductive metals can be cut. The type and thickness of the material depends on the gas used. The gas also affects the quality of the cut. There are a number of different gases and gas mixtures available and we will highlight the main ones:

Compressed air is most commonly used in smaller machines to properly cut steel, stainless steel or aluminum up to 1" thick.

Oxygen is used for fast, high-quality cutting of mild steel up to 1.25 inches thick. It cuts rougher on stainless steel and aluminum.

A mixture of argon and hydrogen produces the hottest plasma arc and is therefore preferred for cutting stainless steel and aluminum up to 3 inches thick.

Nitrogen, when used with high-current equipment, cuts steel and aluminum well up to 3 inches thick.

Today, you don't need a fancy plasma cutter to make the cuts required for most welding jobs. However, it is common to get some burrs along the cut line, the thicker the material, the more burrs you will get, and if there are a lot of burrs they need to be removed before welding.

4. Workspace and safety of CNC plasma cutting machines

In terms of the machine itself, the most important considerations are space and safety. Unlike many hobbyist CNCs, a plasma cutter requires a spacious, well-ventilated area to operate safely. It's not like a 3D printer that can be tucked away in a corner.

Because of the potential for stray sparks, a plasma cutter needs clearance around it from any walls or structures. The area should be large enough so that you can easily walk around the machine. Likewise, the floor should be concrete or other flame-retardant material. You'll also need space for gas cylinders or compressors, and it's worth having a laptop dedicated to operating the machine. If you are using compressed gas cylinders, make sure you follow the safe storage guidelines provided by the manufacturer.

As these machines require a lot of electricity to run, it's important to check the power supply in your workshop before investing. Many machines require a 16A or 32A socket to power the cutter, and you may also need another high current socket to power the compressor. Due to the nature of electricity used by plasma cutters, avoid using an extension cord even if it is rated for the machine's needs.

In addition, due to the extremely high operating temperatures of the plasma arc, there is a high potential for molten metal splashing, high currents, and bright lights emitted by the plasma. Therefore, safety is crucial when using these devices. As we mentioned, you'll need to leave some fireproof area around the machine, and a concrete floor is highly recommended. In terms of personal protective equipment, you will also need the following:

Goggles: try to find a plasma safety mask that will allow you to safely observe the arcs of electricity during operation.

Hand protection: You will need heavy-duty gloves for handling metal.

Body protection: wear a welding suit if you are standing near the table while cutting.

Welding curtains: If there are other people in the work area, then hanging welding curtains will protect their eyes from the glare.

5. Plasma Cutting Machine Application Industries

The ability of plasma cutters to handle heavy cutting jobs at relatively low cost and ease of operation makes them an important tool for many industries. Plasma cutters are ideal for preparing metal sheets that will later be cleaned up for welding or other stages. Plasma can be used in a wide range of metal fabrication industries, and the following are examples for you:

Metal framing: plasma cutting is great for cutting frames and brackets and connections for metal structures. If you're thinking of building your own heavy-duty 3D printer or CNC router, then a plasma cutter will be right up your alley.

Signage: Plasma cutting signage is a business in itself. It usually requires deburring, but once the sign is painted, it looks great.

construction: Large metal plating for buildings or bridges is often cut using a plasma cutter. Industrial machines can even be used to cut structural steel.

industrial machinery: Plasma cut parts are used in the construction of some excavators and other large industrial machines.

Shandong U-May CNC Technology Co., Ltd. was established in 2014 and is located in Jinan, Shandong, China. Our brand name is "UTECH". We always focus on the innovation and research of CNC engraving machines, woodworking milling machines, CNC plasma cutting machines, CNC laser cutting machines and other CNC machinery, providing one-stop CNC solutions. UTECH relies on good technological innovation, good production management and high-quality service, UTECH's machines have been sold to more than 50 countries. In the future, UTECH will continue to focus on the R&D and manufacturing of CNC machinery. We welcome more friends to know us and become partners to create a better future together.