A metal cutting machine is the machine or tool dedicated to cutting metal materials. The metal cutting machine falls into manual, semi-auto, or auto types based on its driven mode. Many metal cutting tools, such as band saws, chop saws, are cheap, flexible, and simple to operate. They are more suitable for metal cutting workshops with small productivity. And sometimes, the manual metal cutting tools provide poor cutting quality with great errors.
For heavy-duty and long-term metal cutting work, the CNC metal cutting machine is the best choice. More and more metalworking companies choose CNC metal cutting machines due to their high automation, excellent precision, and high efficiency.
This article introduces the four most common CNC metal cutting machines, namely laser cutting, plasma cutting, water-jet cutting, and flame cutting. Each machine has its respective advantages, disadvantages, and applicable uses. Among them, the fiber laser and plasma metal cutting machines are the most popular ones. In addition, this article also briefly explains how to choose a CNC metal cutting machine.
What is CNC metal cutting？
Computer numerical controlled metal cutting methods mainly include laser, flame, plasma, and water-jet cutting methods. They can realize automatic, high-efficiency, and high-quality cutting according to the optimized cutting program provided by the CNC nesting software. CNC metal cutting represents a modern high-tech production method. The metal cutting CNC machine is a product of the combination of advanced computer numerical control technology and cutting machinery.
Compared with traditional manual cutting, the metal cutting CNC machine effectively controls and improves the cutting quality and cutting efficiency.
Fiber laser cutting machine
Although high-power CO2 laser machines can also cut stainless steel, it has low efficiency and consumes much energy. Besides, the most common use of a CO2 laser machine is to process organic materials, like wood, acrylic, leather, fabric, and stone. Currently, most sheet metal cutting applications—especially below 6 mm—are mainly done by fiber cutting systems.
The fiber laser cutter is a kind of metal cutting CNC machine. It irradiates a high-density laser beam to the metal surface, and the energy released by the laser melts the metal. The laser head moves above the metal sheet along a certain route given by the computer to form a slit. Then certain shapes are cut off from the sheet.
- The fiber steel metal laser cutting machine adopts a non-contact-based cutting method. This method has a small heat-affected area and leaves no damage to the workpieces. The metal products cut by a fiber laser cutter have tiny heat deformation, excellent precision, and smooth surfaces. There’s no need for further processing.
- The fiber laser beam provides a metal-friendly wavelength, and metal material can absorb the laser energy effectively. The small spot size and excellent beam profile make it ideal for cutting most metals.
- The photoelectric conversion rate of the fiber laser sheet metal cutting machine can reach 30%. This can greatly save power consumption and the use cost is low.
- The laser beam has good quality and stable performance. The laser adopts optical fiber transmission mode instead of easily worn-out reflective lenses. So it basically does not need maintenance.
Plasma cutting machine
The CNC plasma cutting machine is accurate and reliable. However, its precision is a little inferior to that provided by a fiber laser metal cutting machine.
The plasma cutter table uses the heat of a high-temperature plasma arc to partially melt (evaporate) the metal. And it uses the power of the high-speed plasma airflow to remove the molten metal to form the incision. When the metal sheet exceeds 20mm thick, the plasma cutting machine is more advantageous than the steel metal laser cutting machine.
A CNC plasma table can cut many materials that are difficult to cut by traditional methods. In terms of cutting speed, the CNC plasma cutter is several times faster than the traditional oxygen cutting when cutting thin carbon steel sheets. At the same time, the cutting surface remains smooth and the thermal deformation is small.
The plasma CNC cutting machine has many advantages such as simple operation, high accuracy, high efficiency, and low labor intensity. It is widely used in automobiles, locomotives, pressure vessels, chemical machinery, nuclear industry, general machinery, engineering machinery, steel structures, etc.
Flaming cutting machine
Flame cutting is also known as gas cutting or oxygen-fuel cutting. The CNC flame cutting machine uses the thermal energy of the gas flame to pre-heat the workpieces to a certain temperature. Then it ejects high-speed cutting airflow to melt the metal and release heat to achieve the purpose of cutting.
The commonly used flame cutting gases include acetylene, propane, liquefied gas, coke oven gas, natural gas, etc. From the comprehensive consideration of pollution, energy consumption, and cost ratio, natural gas is currently the most suitable gas. But natural gas also has its limitations. For instance, the natural gas flame temperature is not high, which causes the cutting efficiency to be inferior to acetylene.
The CNC flame metal cutting machine can cut large-thickness metal plates. It can cut metal plates with thicknesses ranging from 1mm to 1.2m. Meanwhile, the cutting costs are low. However, its heat-affected area is relatively larger, and the material is more prone to thermal deformation. Therefore, the cutting accuracy of the flame metal cutting machine is relatively inferior to other cutting methods.
Water-jet cutting machine
The CNC water-jet cutting machine is a machine that uses high-pressure water to cut. With the continuous improvement of technology, garnet sand, emery, and other abrasives are mixed in high-pressure water to assist cutting. This greatly improves the cutting speed and cutting thickness of the CNC water-jet metal cutting machine.
Only the water-jet cutting belongs to the cold cutting mode compared with laser cutting, plasma cutting, and flame cutting. It directly uses the kinetic energy of the abrasive water jet to cut the metals. The heat generated during cutting is immediately taken away by the high-speed water jet. And the cutting process produces no harmful substances and no thermal effect on the metals.
It has advantages of no influence on the physical and chemical properties of the cutting material. And also no thermal deformation, narrow slitting, high precision, smooth cut surface, clean and pollution-free. It can process materials that cannot be processed or are difficult to process with traditional processing methods. For example, glass, ceramics, composite materials, reflective materials, chemical fibers, heat-sensitive materials, etc.
Compare Four Different CNC Metal Cutting Machine
| Metal cutting method | Cutting thickness (approx.) | Characteristics | Price range (approx.) |
| Laser cutting | 0.1-20mm | Highest precision Excellent cutting quality | $10,000-$100,000 |
| Plasma cutting | 0.5-100mm | High precision Fast cutting speed | $2,000-$9,000 |
| Flame cutting | 4-150mm | Maximum cutting thickness Less precision | $2,000-$5,000 |
| Water-jet cutting | <100mm | No heat effect Cut organic materials | $9,000-$40,000 |
Laser metal cutting machines are mainly for cutting metals that are not easily oxidized. For example, stainless steel, titanium, aluminum, and their alloys. It can give full play to its greatest advantages when cutting thin metal plates and tubes. The steel laser cutting machine has a faster cutting speed and the highest precision among the four metal cutting methods. Its positioning accuracy can reach 0.03mm, and the repeat positioning accuracy can reach 0.02mm. In addition to cutting, it can also engrave thin metal without affecting the material.
A plasma metal cutting machine with different working gas can cut all kinds of metals that are difficult to cut by oxygen. Especially for non-ferrous metals (stainless steel, carbon steel, aluminum, copper, titanium, nickel), the cutting effect is better. Plasma cutting has a certain thermal effect and its accuracy is lower than that of laser cutting machines. It is not easy to perform secondary processing on the cut surface. The CNC plasma table can cut thicker metal plates than the fiber laser cutter.
The advantage of the CNC flame metal cutting is that it can cut very thick metals, like the steel several inches thick. However, it can only cut fewer types of metal materials, including carbon steel, low alloy steel, and cast iron. Most other types of materials will not be cut cleanly by flame cutting. Flame cutting is also generally slower than plasma cutting and water-jet cutting. The accuracy of flame cutting is generally not very high.
Water-jet cutting can cut many different types of materials, not just metals. Water-jet cutting is also much cleaner than plasma or flame cutting because it does not emit dangerous fumes. It is not suitable for thick cuts on hard metals. A water-jet metal cutting machine is expensive and may require considerable maintenance.
Next time, we will introduce how to select a suitable metal cutting machine for you.
