CNC Plasma refers to a system where a metal cutting machine carrying a torch is guided by a computer. The acronym CNC stands for “Computer Numerical Control.” In such a system, a numerical code directs the path the torch should follow. Hand torches are often used to cut small metal plates. However, when large metal plates are involved, it is almost impossible to achieve the desired accuracy level by hand. This is where CNC Plasma cutting machines or waterjet cutting machines come in handy.
The plasma torch forces compressed air or gas at high speeds through a nozzle to cut metals. When that air or gas is ignited by an electrical arc, it turns into plasma, also called ionized gas. This plasma, in turn, cuts through the metal.
CNC plasma cutters come in various prices depending on size and functionality. They are highly accurate and cut through metals at considerable speeds. They can slice metal at a speed of up to 500 inches per minute. A plasma cutter needs two types of gases to function properly: a plasma gas and an assist gas. Those gases may vary depending on the type of metal to be sliced.
Companies like Fast Cut CNC provide cutting-edge CNC systems that deliver precision and speed for professional-grade plasma cutting. The plasma used in CNC differs from those designed for handheld cutting tools. CNC uses a mechanized plasma system consisting of a straight-barrelled torch. Such a torch is supported by a machine, and the CNC controls it using an interface.
The CNC can be a stand-alone controller using an interface or a Windows laptop computer that communicates with the machine drive through the ethernet ports using special software.
To direct the motion of the torch, the CNC uses part programs, commonly referred to as “M-codes” and “G-codes.” Those programs are text files that determine the contour of the part to be cut and the on-and-off sequences of the torch. Those “M-codes” and “G-codes” originate from a part geometry generated by a CAD file, which is translated by a piece of software called a “post-processor.”
When operating a CNC plasma cutter, space and safety are two factors that need to be considered. The machine must be placed in a well-ventilated area with ample space for safe operation. There should be enough space to serve as a buffer, as stray parks are expected when the plasma cutter operates. Attention should also be given to the type of floor used in the area of operation. The floor should be made out of concrete or other fire-resistant material. An appropriate amount of space should also be allocated for the gas compressor and the computer.
1. What is a CNC Plasma Cutting System?
A CNC plasma cutting system uses a plasma torch operated by a computer to cut through electrically conductive materials like steel, aluminum, brass, and copper. The torch generates a hot plasma jet (ionized gas) that melts the material, while compressed air or another gas blows the molten material away, leaving a clean, sharp edge.
2. Components of CNC Plasma Cutting Systems
- CNC Controller: The computer that controls the movement of the cutting torch based on programmed coordinates (CAD/CAM software). It ensures accurate and precise cuts.
- Plasma Torch: The tool that creates the plasma arc for cutting. It typically consists of an electrode, nozzle, and gas or water cooling system.
- Cutting Table: The surface where the material (sheet metal or other conductive material) is placed for cutting.
- Drive System: Motors and guides that move the torch along the X, Y, and sometimes Z axes.
- Air/Gas Supply: Compressed air or gas (like nitrogen or oxygen) used to create the plasma and clear away molten metal.
3. How It Works
- Design Phase: CAD (Computer-Aided Design) software is used to create or import the desired shape/design. CAM (Computer-Aided Manufacturing) software translates this design into machine instructions (G-code).
- Torch Movement: The CNC controller uses G-code to move the plasma torch precisely along the programmed path, controlling speed, height, and other parameters.
- Cutting Process: The plasma torch generates an electrical arc between an electrode and the material’s surface, creating plasma that reaches temperatures up to 20,000°C (36,000°F) to cut through the metal. The high-speed gas blows away the molten material, leaving a clean edge.
4. Types of CNC Plasma Cutting Systems
- 2D Plasma Cutters: These systems cut flat sheet metal into 2D shapes using X and Y axes.
- 3D Plasma Cutters: Capable of cutting materials at different angles, often used for cutting pipes and creating complex shapes.
- Portable CNC Plasma Cutters: Lightweight and designed for smaller jobs, often for fieldwork or smaller workshops.
5. Advantages
- Precision: CNC plasma systems offer high accuracy and detailed cutting for complex designs.
- Speed: Faster than manual cutting or other thermal cutting methods.
- Versatility: Can cut various metals, including ferrous and non-ferrous materials.
- Cost-Effective: Suitable for both small-scale and large-scale operations, optimizing material usage.
6. Applications
- Manufacturing: Used in automotive, aerospace, and machinery industries for fabricating parts.
- Artistic Projects: Creating metal sculptures, signage, and decorative pieces.
- Construction: Cutting beams, pipes, and structural components.
- Repair and Maintenance: For repair work on equipment and vehicles.
CNC plasma cutting systems are valuable tools in industries requiring precision metal cutting. They offer speed, efficiency, and flexibility in producing a wide range of products.
The computer should be plugged into a UPS (Uninterruptible Power Supply) to ensure continuous power supply. It should also be earth-grounded to prevent interference with the electrical arc generated by the CNC plasma cutter.
Because of their simplicity, speed, and accuracy, CNC plasma metal cutting systems are great for industrial applications and hobbies.
