Plasma Cutter

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Definition

Plasma cutting is a processing method that uses the heat of a high-temperature plasma arc to melt (and evaporate) the metal part or part of the cut of the workpiece and to remove the molten metal by the momentum of high-speed plasma to form the cut. A plasma cutter is a machine tool that uses plasma cutting technology to process metal materials.

plasma cutter

Working Principle

Plasma is a gas that is heated to a very high temperature and is highly ionized. It will transfer the arc power to the workpiece. The high heat will melt the workpiece and be blown away, forming a working state of plasma arc cutting.

After the compressed air enters the torch, it is distributed by the gas chamber in two ways, that is, plasma gas and auxiliary gas are formed. The plasma gas arc acts to melt the metal, while the auxiliary gas cools the various parts of the torch and blows away the molten metal.

The cutting power supply consists of two parts, the main circuit, and the control circuit. The electrical principle: the main circuit consists of a contactor, a high-leakage three-phase power transformer, a three-phase bridge rectifier, a high-frequency arc starting coil, and protection components. The external characteristics of the power supply are caused by high leakage resistance. The control circuit completes the entire cutting process through the button switch on the torch:

Pre-ventilation-main circuit power supply-high frequency arc starting-cutting process-breathing arc-stop.

The power supply of the main circuit is controlled by the contractor; the passage of gas is controlled by the solenoid valve; the control circuit controls the high-frequency oscillator to ignite the arc and stop the high-frequency operation after the arc is established.

In addition, the control circuit still has the following internal locking function: the thermal control switch operates and stops working.

Features

Plasma cutter 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 main advantage is that the cutting thickness is not For large metals, the plasma cutting speed is fast, especially when cutting ordinary carbon steel sheets, the speed can reach 5-6 times of the oxygen cutting method, the cutting surface is smooth, the thermal deformation is small, and there is almost no heat-affected zone.

Plasma cutter, the working gas that can be used (working gas is the conductive medium of the plasma arc, and it is also a heat carrier, while also excluding the molten metal in the cut), the plasma arc cutting characteristics, cutting quality, speed are obvious influences. Commonly used plasma arc working gases are argon, hydrogen, nitrogen, oxygen, air, water vapor, and some mixed gases.

Plasma cutting machine is widely used in automobiles, locomotives, pressure vessels, chemical machinery, nuclear industry, general machinery, engineering machinery, steel structure, and other industries.

It is safe, simple, effective, versatile and environmentally friendly to obtain hot plasma processing (cutting, welding, brazing, quenching, spraying, etc.) of metal with a thickness of more than 0.3mm by obtaining plasma from water vapor It is the first in the history of the processing industry.

The essence of the working process of the plasma equipment is this: an arc is generated between the nozzle (anode) and the electrode (cathode) inside the gun, so that the moisture between them is ionized to achieve the plasma state. At this time, the ionized steam is sprayed out of the nozzle in the form of a plasma beam under the pressure generated inside, and its temperature is about 8 000 ° С. In this way, non-combustible materials are cut, welded, welded, and processed in other forms of heat treatment.

Benefits and Advantages

1. The frame adopts an all-welded structure, strong and reasonable, simple operation, durable.

2. Fast cutting speed and high precision. The cutting port is small, neat, and there is no dross. Based on the traditional numerical control system, the control method for cutting is improved to avoid secondary trimming.

3. Suitable for low carbon steel plate, copper plate, iron plate, aluminum plate, galvanized plate, titanium gold plate, and other metal plates.

4. The CNC system configuration is high. Automatic arc starting, stable performance, and success rate of arc starting reach over 99%.

5. Support standard G code path files generated by Wentai, Beihang Haier, ARTCAM, Type3, and other software. The control system uses U disk to exchange processing files, which is convenient and fast to operate.

Applications

The advantages of the plasma cutting machine are that the plasma arc energy is more concentrated, the temperature is higher, the cutting speed is faster, the deformation is small, and stainless steel, aluminum, and other materials can also be cut.

The disadvantages of plasma cutting are arc intensity, noise, dust, and pollution to the environment. For medium and heavy thickness, underwater plasma cutting is used, and the cutting thickness is also limited. Similarly, gas flow, arc length, telegram quality, current size, and cutting speed all affect the quality. It is not easy to master if you are not good at mastering. It is not as simple as flame cutting. Plasma cutting guns are not suitable, because the cutting speed is fast, and it is easy to be uncoordinated by the above factors, which makes the cutting quality different. Generally speaking, for thin plate cutting, the surface quality of plasma cutting is better than that of fire filling, and there is very little slag.

In recent years, manufacturers have developed new technologies called fine plasma or high-precision plasma, with good results. By improving the cutting moment design, the quality of the cutting surface of the workpiece is significantly improved, and the verticality of the edge can reach 0-1.5 °, which is especially beneficial to improve the cutting quality of thick plates. Due to the improved cutting gun, the electrode life has been increased several times. However, the distance between the torch and the steel plate is relatively high, and the height sensor on the torch is required to be more sensitive and the torch response is faster.

Therefore, the use of plasma cutting 4-30 mm steel plate is an ideal method, which can avoid the shortcomings of low cutting speed, large deformation, serious incision, and serious slag hanging. Obtained a certain thickness of stainless steel and other materials.