Several notice for cnc plasma cutting
Plasma arc cutting is a processing method that uses the heat of high temperature plasma arc to melt (and evaporate) the metal part or localate at the incision of the workpiece, and excludes the molten metal from the momentum of high-speed plasma to form the incision. Plasma arc cutters are machinery that processes metal materials with the help of plasma cutting technology.
I.Industrial use
CNC plasma cutting machine with different working gases can cut a variety of oxygen-acetylene cutting difficult-to-cut metals, especially for non-ferrous metals (stainless steel, aluminum, copper, titanium, nickel) cutting effect is better, its main advantage is that cutting the thickness of the metal, plasma cutting speed, especially when cutting ordinary carbon steel sheet, the speed can reach 5-6 times oxygen-acetylene cutting method, cutting surface finish, thermal deformation small, less thermal impact.
Plasma cutting machines are widely used in automobiles, locomotives, pressure vessels, chemical machinery, nuclear industry, general machinery, engineering machinery, steel structures, ships and other industries.
II. working gas
Plasma cutting development to the present, can be used working gas (working gas is the conductive medium of the plasma arc, but also carrying heat body, but also to exclude the melting metal in the cut) on the plasma arc cutting characteristics and cutting quality, speed have a clear impact. Common plasma arc operating gases are argon, hydrogen, nitrogen, oxygen, air, water vapor, and certain mixtures.
III. cutting norms
Various plasma arc cutting process parameters directly affect the stability of the cutting process, cutting quality and effect. The main cutting specifications are summarized below:
1. Empty voltage and arc column voltage
Plasma cutting power supply, must have a high enough empty load voltage, in order to easily lead the arc and make the plasma arc burning steadily. The empty load voltage is generally 120 to 600V, while the arc column voltage is generally half of the empty load voltage. Increasing the arc column voltage can significantly increase the power of the plasma arc, thus increasing the cutting speed and cutting a larger thickness of the metal sheet. Arc column voltage is often achieved by regulating the gas flow and increasing the shrinkage of the electrode, but the arc column voltage cannot exceed 65% of the empty voltage, otherwise the plasma arc will be unstable.
2. Cutting current
Increasing the cutting current also increases the power of the plasma arc, but it is limited by the maximum allowable current, otherwise it will make the plasma arc column thicker, the width of the cut, and the electrode life decrease.
3. Gas flow
Increasing the gas flow can not only increase the arc column voltage, but also enhance the compression of the arc column, so that the plasma arc energy is more concentrated, the injection force is stronger, thus improving the cutting speed and quality. However, the gas flow is too large, but will make the arc column shorter, the loss of heat increased, so that the cutting capacity is weakened, until the cutting process can not be carried out normally.
4. Electrode shrinkage
The so-called internal shrinkage refers to the distance from the electrode to the end face of the cut mouth, the appropriate distance can make the arc in the cut mouth to get a good compression, to obtain energy concentration, high temperature of the plasma arc and effective cutting. Too large or too small distance, will cause the electrode serious burn, cut the mouth burned and reduce the cutting capacity. The internal shrinkage is generally taken from 8 to 11mm.
5. Cut mouth height
The height of the cut is the distance from the end face of the cut to the surface of the cut workpiece. The distance is generally 4 to 10mm. It is the same as the shrinkage of the electrode, the distance should be appropriate in order to give full play to the cutting efficiency of the plasma arc, otherwise it will reduce the cutting efficiency and cutting quality or make the cut mouth burned.
6.Cutting speed
The above factors directly affect the compression effect of the plasma arc, that is, affect the temperature and energy density of the plasma arc, and the high temperature and high energy of the plasma arc determine the cutting speed, so the above factors are related to the cutting speed. Under the premise of ensuring the quality of cutting, the cutting speed should be increased as much as possible. This not only increases productivity, but also reduces the amount of deformation of the cut part and the thermal impact area of the cut area. If the cutting speed is not suitable, the effect is reversed, and will increase the slag, the cutting quality is reduced.
IV. Cutting method
In addition to the general form of plasma cutting method, derived form also has water compression plasma cutting. The most common methods are general plasma cutting and air plasma cutting.
General plasma cutting does not require protective gas, and the working gas and cutting gas are ejected from the same nozzle. When radiating, small airion ion gas is ejected as a dinosmodolic medium, and when cutting, large air gas is ejected at the same time to eliminate melting metal.
Air plasma cutting generally uses compressed air as ion gas, this method cutting costs are low, the source of air source is convenient. Compressed air is heated, decomposed and ionist in the arc, and the resulting oxygen cutting metal produces a chemical heat ingress reaction that speeds up the cutting speed. Fully ionised air plasma has a high thermal crucible value, so the arc has a large energy and fast cutting speed.
V. Cutting equipment
Plasma cutting system is mainly composed of water supply device, power supply and cutting gun. The water-cooled gun also needs to have a cooling circulating water device.
1. Gas supply device: air plasma arc cutting of the main equipment is a larger than l.5kw air compressor, cutting the required gas pressure of 0.3 to 0.6MPa. If other gases are selected, bottled gas can be used for cutting after decompression.
2. Power supply: Plasma cutting uses a DC power supply with steep drop or constant current external characteristics. In order to obtain satisfactory arcing and steady arc ingresss, the empty voltage of the power supply is generally twice that of the arc. The commonly used cutting power supply has an empty voltage of 350 to 400V.
3. Cut gun: the specific form of the cut gun depends on the current level of the cutting gun, generally 60A below the use of air-cooled structure, and 60A or more cut guns use water-cooled structure. The electrodes in the cutting gun can be used pure tungsten, tantalum tungsten, bell tungsten rod, or inlaid electrodes. Cast tungsten is preferred in the electrode material.
Plasma cutting has the advantages of large cutting thickness, flexible cutting, simple clamping workpiece and cutting curve, can be widely used in all metal materials and non-gold chip material cutting.
VI. Security protection
1. The lower part of plasma cutting should be set up sink, in the cutting process cutting part should be placed underwater cutting, to avoid the production of smoke poisoning to the human body.
2. Avoid direct visual arcing during plasma arc cutting, wear professional protective glasses and face cover, avoid arcing burns to the eyes and skin.
3. In the plasma arc cutting process will produce a large number of toxic gases, need ventilation and wear multi-layer filter dust mask.
4. In the plasma arc cutting process should wear towels, gloves, foot sheaths and other protective equipment, to prevent the splatter of Mars on the skin burns.
5. High-frequency and electromagnetic radiation generated by high-frequency oscillators during plasma arc cutting will cause damage to the body, some long-term practitioners even appear to be infertile symptoms, although the medical profession and the industry has not yet finalized, but still need to do a good job of protection.
Hubei Meisar CNC Technology Co. , Ltd. is a professional production of CNC cutting machine, CNC flame cutting machine, CNC plasma cutting machine, CNC multi-head straight cutting machine, CNC flame plasma two-use cutting machine, gantry CNC cutting machine, long door CNC flame cutting machine Machine, gantry cnc plasma cutting machine, line cutting machine, pipe CNC cutting machine, bevel cutting machine, square pipe cutting machine, shaped pipe cutting machine, portable CNC cutting machine, small bee plasma cutting machine, wind pipe plasma cutting machine, Industrial tabletop CNC cutting machine, laser cutting machine, laser tube cutting machine, laser square tube cutting machine, laser tube cutting machine and so on.
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