The principle of operation of a plasma cutter. What is plasma cutting of metals - description of technology

One of the popular types of metal processing is its cutting. There are many ways to obtain the required shape from a single sheet, but in this material we will look at the principle of operation of plasma cutting.

Plasma cutting. In fact, there is a golden mean. The advantages of cutting metal with plasma combine all of the above technologies. The main advantage is that there are no restrictions on the type of material processed. Just in terms of thickness.

• aluminum alloys 120 mm
• copper alloys 80 mm
• steel 50 mm
• cast iron 90 mm

The equipment varies from industrial to household, so the technology is accessible to everyone. Let's take a closer look at it.

Plasma cutting of metal - operating principle

A two-component medium acts as a cutter:

• Electric arc operating according to classic scheme– discharge between cathode and anode. Moreover, the material itself can act as an anode if it is a conductor.
• Gas arc. Heating up under the influence electric arc(the temperature reaches 25000º C), the gas is ionized and turns into a conductor of electric current.

The principle of operation of plasma cutting is shown in detail in this video.

As a result, plasma is formed, which is fed under high pressure into the cutting area. This hot gas stream literally evaporates the metal, and only in work area. Despite the fact that the temperature of plasma cutting is measured in tens of thousands of degrees, there is practically no impact on the boundary zone.

Important! Correctly selected speed allows you to get a very narrow cut without damaging the edge of the material.

The source of plasma cutting is a plasma torch.


His task is to light the arc, maintain operating temperature, and blow molten metal out of the cutting area. Since plasma cutters are designed to process any hard materials, including dielectrics - the formation of an electric arc is carried out in two ways:


Figure a) shows a direct action cutter. Cathode assembly (8) along with the assigned cathode (6) are one of the electrodes. The second electrode (anode) is workpiece (4)– a metal with good electrical conductivity.

The power cable of the plasma torch is connected to it. Plasma cutting tip (5) in this scheme it acts as a housing. From separated from the cathode insulator (7). Gas is supplied inside fitting (1) and forms a plasma jet consisting of electric (2) and gas (3) arc.

What is the device

Device structure

The plasma cutter is a rather complex apparatus, consisting of several main components:

Plasma torch

This element is a plasma cutter, in fact, the main element of the device that produces plasma. The plasma torch is connected to other elements of the device using a cable and hose through which air and electric current are supplied.

It must be said that there are two types of cutters:

• Direct action. An arc occurs between the metal workpiece and the cutter. These are the plasma torches that are used to work with metal;

• Indirect. The arc discharge occurs inside the plasma torch itself. This allows the machine to be used for cutting non-metallic materials.
  The plasma torch contains two main elements:
• Nozzle. This part forms a plasma jet. The metal cutting speed, cut size and cooling intensity depend on its diameter and length.
  As a rule, the nozzle diameter does not exceed 3 millimeters, and the length is 9-12 millimeters. The longer the length, the better the quality of the cut, but the less durability of the nozzle itself. That's why best option when the length of the nozzle is one and a half times greater than its width;

• Electrode. A metal rod, usually made of hafnium. The electrode provides excitation of the electric arc for air plasma cutting.

Power supply

The job of the power source is to supply current to the plasmatron. There are two types of power supplies:

• Transformer. They are weighty and consume a lot of energy, but they are less sensitive to temperature changes. In addition, the thickness of the workpiece that the machine is capable of cutting can reach 40-50 mm;

• Inverters. Lighter, more compact and energy efficient. In addition, inverters provide a more stable arc.
  The disadvantages are that they can be used for cutting sheets no more than 30 millimeters thick.

Compressor

To operate a plasma cutter, gas is required, which ensures the formation of plasma and is responsible for cooling the plasma torch. Therefore, a compressor is used to supply gas to the nozzle.

In devices with a current not exceeding 200 A, air is used as a gas. Such a machine can cut workpieces up to 50 millimeters thick.

An industrial machine works with other gases such as argon, helium, nitrogen, hydrogen, etc.

Cable-hose package

As I said above, this element combines the individual components of the device into a plasma cutter, i.e. The hose supplies gas to the nozzle, and the cable supplies current to the electrode.

Operating principle

What is plasma

We’ve figured out the devices of the device, now let’s look at how a plasma cutting machine works, and what the word “plasma” actually means. So, plasma is heated to high temperature air or other gas in an ionized state. The heating temperature can reach 30,000 degrees.

The operating principle of the device is as follows:

1. When the ignition button is pressed, high frequency currents are supplied to the electrode;
2. A pilot arc is formed between the nozzle and the electrode, the temperature of which reaches 8000 degrees;
3. Then compressed air is supplied to the nozzle;
4. The air breaks through the arc, as a result of which it heats up and increases in volume a hundred times. In this case, it is ionized, and the air acquires conductive properties;
5. When the plasma comes into contact with the workpiece, a cutting arc is formed, and the pilot arc goes out. As a result, the metal is easily cut, and the air is blown away from the cutting line.

You can make a plasma cutting machine yourself. An inverter is usually used for this welding machine, however, you can make the device “from scratch”, using the diagrams available on the Internet.

Nuances of choice

When choosing a plasma cutter, you need to pay attention to the following points:

• Versatility. There are devices that can be used not only for cutting metal, but also for stick electrode welding, as well as for argon arc welding.
  However, it should be remembered that versatility usually has a bad effect on the quality of operations performed and productivity. As a rule, a universal plasma cutter cannot cut workpieces thicker than 11 mm;
• Current strength. The higher the current, the hotter the arc heats up; accordingly, the faster plasma cutting is performed, and the maximum thickness of the part that can be cut using this method increases.
  Therefore, you first need to decide for what purposes you need a plasma cutter, i.e. what parts you will have to work with. If you are cutting steel up to 20 mm thick, a device with a current of 20 A will be sufficient.
  If the thickness of the metal is greater, then a more powerful plasma cutter will be needed - with a current of 40-60 A. For industrial devices, the current can reach 200 A or more;

• Electrical network type. Household plasma cutting machines can operate on a 220 V network, but their current strength, as a rule, does not exceed 40 A. Industrial machines operate on a 380 V network;
• Duration of activation. Each plasma cutter has such a characteristic as PV, which is calculated as a percentage. This indicator indicates the time that the device can operate.
  The basis is a working cycle of 10 minutes. If the PV is, for example, 70%, then the plasma cutter can work for 7 minutes, after which it must cool down for 3 minutes. If the indicator is 40%, then the device can operate for no more than 4 minutes, after which it must cool down for 6 minutes.
  There are devices with 100% duty cycle that can be used continuously. They usually have water cooling;
• Compressor. The plasma cutter can have a built-in or separate connected compressor. For domestic purposes, devices with a built-in compressor are more convenient, but they are low-power.
  If a plasma cutter is needed for professional work, a separate compressor is required. The main requirement for the compressor is to provide the plasmatron with constant air pressure, i.e. without pulsations, and the air must be dry. In addition, the air pressure created by the compressor must necessarily meet the requirements of the device;

• Convenience. The plasma cutter must have a sufficient length of cable and hose package. If the device is needed for domestic purposes, it is desirable that it be compact and easy to transport.

A plasma cutting machine must be purchased with a small power reserve - this will increase its durability.

Brief overview of models

Finally, we will briefly consider several devices that have received positive reviews from users. These include:

• FoxWeld Plasma 33 Multi;
• TelWin Plasma 60 HF;
• Svarog;
• Resanta IPR-25;
• Gorynych.

FoxWeld Plasma 33 Multi

This model is a multifunctional household device for plasma cutting, operating on a 220 V network. Its main feature is the ability to be used as a welding machine for manual arc welding.

The maximum cutting current of this model is 30 A. This allows it to cut 8 mm thick steel.

Price of this device is 33,000 rubles (the price is current for spring 2017).

TelWin Plasma 60 HF

This model can be classified as industrial, since it has a relatively high power - the current is 60 A, and it is also designed to operate from a 380 V network.

The device can cut steel up to 20 mm thick. In addition, the manufacturer draws attention to the following advantages of the model:

• The presence of a microprocessor that controls many parameters of the device;
• Possibility of adjusting current strength;
• The built-in pressure gauge allows you to monitor air pressure.

This plasma cutter costs 110,142 rubles.

Svarog CUT-40

This model is a powerful household plasma cutter, the current of which reaches 40 A. This allows it to cut steel up to 12 mm thick. PV at maximum current is 60%, for household appliances this figure is quite high.

It should be noted that despite the Slavic name “Svarog”, this device is produced in China. But, despite this, users have no complaints about its quality and reliability.

The cost of Svarog CUT-40 is 33,000 rubles.

Resanta IPR-25

Resanta is another Chinese-made household plasma cutter with a current of 25 A. The manufacturer claims that this “baby” is capable of cutting metal up to 12 mm thick.

Another advantage of this device is its relatively low cost - the price is 28,900 rubles.

Gorynych

Gorynych is a multifunctional device from a domestic manufacturer. In addition to plasma cutting, electric welding is also available to him.

Gorynych’s current strength is not large, 3–10 A, which allows him to cut metal up to 8 mm thick. Its main feature, in addition to its versatility, is water cooling. This allows the device to work continuously for 25 minutes.

In addition, it is very compact - the weight of the device does not exceed 0.7 kg. The price is within 43,000 rubles.

Conclusion

Now you know how a plasma cutter works and what to look for first when choosing one. Additionally, I recommend watching the video in this article. If any nuances are not clear to you, write comments, and I will be happy to answer you.

The use of plasma cutting is widespread. It is used in mechanical engineering, utilities, shipbuilding, and the manufacture of metal structures. Plasma cutting is based on the principle that ionized air begins to conduct electrical current.

Metal cutting is carried out by plasma, which is heated ionized air, and a plasma arc. The operating principles characteristic of plasma cutting of metal will be described below.

What is plasma cutting

When cutting metal with plasma, the electric arc intensifies. This is possible due to the action of gas under pressure. The cutting element is heated to high temperatures, resulting in high-quality and fast cutting of metal.

Unlike its plasma counterpart, it does not contribute to overheating of the entire processed product. High temperature occurs directly at the place where the metal is cut, and the remaining parts of the product do not heat up and are not deformed.

The principle of plasma cutting of metal is based on:

• delivery of the required voltage by a current source (standard voltage - 220 V, increased voltage - 380 V, for cutting metal at large enterprises);
• transmitting current to the plasma torch (torch) through cables, as a result, an electric arc lights up between the anode and cathode;
• supply of air flows through hoses by a compressor to the device;
• the action of swirlers inside the plasmatron that direct flows to the electric arc;
• the passage of vortex air flows through an electric arc and the creation of ionizing air heated to high temperatures;
• closing the working arc between the electrode and the surface being treated when the plasma torch is brought to it;
• exposure to air under high pressure and high temperature on the product being processed.

The result is a thin cut with minimal sagging.

The arc can burn in standby mode if the device is not used at a specific time. During standby mode, combustion is maintained automatically. When the torch is brought to the workpiece, the arc instantly goes into operating mode and instantly cuts the metal.

After turning off the device, it is purged to remove debris and cool the electrodes.

The electric arc is universal in its action. It is capable of not only cutting, but also welding metal products. For welding, filler wire suitable for the specific type of metal is used. It is not air that is passed through the arc, but an inert gas.

Plasma cutter structure

The name of the device used for cutting metal products different ways. The unit structure includes the following elements:

• electrical power source;
• compressor;
• plasmatron;
• cable hoses.

Several devices act as power sources:

• inverter;
• transformer.

Each device has a number of advantages and disadvantages. The advantages of the inverter include:

• cheapness;
• arc stability;
• ease of use in areas with difficult access;
• light weight;
• high efficiency, exceeding that of a transformer by 30%;
• efficiency.

What are the disadvantages and limitations?

The main disadvantage of the inverter is the inability to use it for cutting thick metal products.

The transformer is effectively used when cutting thick-walled metal that an inverter cannot handle. It can withstand fluctuations in mains voltage, but is characterized by low efficiency. Transformers are inconvenient due to their heavy weight.

A compressor is a device that supplies air to an electric arc. The mechanism contributes to the creation of vortex air flows directed towards it. The compressor ensures that the arc cathode spot is clearly located in the center of the electrode. If the process is disrupted, consequences arise in the form of:

• formation of two electric arcs at once;
• weak arc burning;
• plasma torch failure.

During the operation of a conventional non-industrial plasma cutter, only compressed air is passed through the compressor. It creates plasma and cools the electrodes. Industrial units use mixtures of gases based on oxygen, helium, nitrogen, argon, and hydrogen.

The plasma torch performs the main function of the device - cutting the product. His device includes:

• cooler;
• electrode;
• cap;
• nozzle.

The plasmatron contains a hafnium electrode that excites the electric arc. Zirconium, less often beryllium and thorium electrodes are used. Their oxides are toxic and even radioactive.

A plasma jet passes through the plasmatron nozzle, cutting the products. The quality of cutting, technology, speed of operation of the unit, width of the cut and cooling rate depend on its diameter.

The cable carries current coming from the inverter or transformer. Compressed air moves through the hoses, forming plasma in the plasma torch.

A sequential study of the stages of plasma cutting of metals allows you to understand how it works:

• the ignition button is pressed, leading to the start of current supply from the transformer or inverter to the plasmatron;
• a pilot electric arc with a temperature of 70000C appears inside the plasmatron;
• an arc is ignited between the nozzle tip and the electrode;
• compressed air enters the chamber, which passes through the arc, heating and ionizing;
• in the nozzle the incoming air is compressed, escaping from it in a single stream at a speed of 3 m/s;
• the compressed air escaping from the nozzle heats up to 300,000C, turning into plasma;
• when the plasma comes into contact with the product, the pilot arc goes out and the cutting (working) arc lights up;
• the working arc melts the metal at the point of impact, the result is a cut;
• parts of the molten metal are blown away from the product by air currents escaping from the nozzle.

Any plasma metal cutting technology depends on the cutting speed and air flow. High speed results in a finer cut. At low speed and high amperage, the cutting width becomes wider.

With increased air flow, the cutting speed increases. How larger diameter nozzles, the lower the speed and the wider the cut.

Cutting techniques

In practice, two methods of cutting metal with plasma are used:

• plasma jet;
• plasma-arc method.

Plasma jet cutting has found application in the processing of non-metallic products that are not capable of conducting electric current. With this processing method, the product is not part of the electrical circuit. The arc burns between the electrode and the tip of the plasma torch. The product is cut by a plasma jet.

The plasma-arc method is widely used. It is used for:

• cutting profiles, pipes;
• manufacturing products with straight contours;
• casting processing;
• forming holes in metal;
• production of welding blanks.

The arc burns between the electrode and the workpiece. The arc column is combined with the plasma jet. The jet occurs due to the gas blown through the operating compressor, which becomes very hot and ionized in the process. The gas promotes the formation of plasma, and due to its high temperature, the cutting speed of the metal being processed increases. This method involves the use of a direct current arc with straight polarity.

Types of plasma cutting

There are three types of process:

• simple - using electric current and air (an alternative is nitrogen);
• using water, which performs the function of cooling the plasmatron, protecting it and absorbing emissions;
• with the use of protective gas, which improves the quality of the cut.

Pros and cons of plasma cutting machines

) plasma jet is called plasma cutting. The plasma flow is formed as a result of gas blowing into a compressed electric arc. The gas then heats up and ionizes (breaks down into negatively and positively charged particles). The temperature of the plasma flow is about 15 thousand degrees Celsius.

Types and methods of cutting using plasma

Plasma cutting can be:

• superficial;
• dividing

In practice, separation plasma cutting has found wide application. Surface cutting is used extremely rarely.

The cutting itself is carried out in two ways:

• plasma arc. When cutting steel using this method, the metal being cut is included in electrical circuit. An arc is formed between the tungsten electrode of the torch and the workpiece.

• plasma jet. An arc occurs in the cutter between two electrodes. The product being cut is not included in the electrical circuit.

Plasma cutting is more productive than oxygen cutting. But if thick material or titanium is being cut, then preference should be given to oxygen cutting. Plasma cutting is indispensable when cutting (especially).

Types of gases used for plasma cutting.

Gases used to form plasma are:

• active - oxygen, air. Used when cutting ferrous metals
• inactive - nitrogen, argon, . Used for cutting non-ferrous metals and alloys.

1. Compressed air. Used for cutting:

• copper and its alloys – with a thickness of up to 60 mm;
• aluminum and its alloys – with a thickness of up to 70 mm;
• steel – with a thickness of up to 60 mm.

1. Nitrogen with argon. Used for cutting:

• high-alloy steel up to 50 mm thick.

It is not recommended to use this gas mixture for cutting copper, aluminum, and black steel;

1. Pure nitrogen. Used for cutting (h=material thickness):

• copper h equal to 20 mm;
• brass h equal to 90 mm;
• aluminum and its alloys h equal to 20 mm;
• high-alloy steels h equal to 75 mm, low-alloy and low-carbon steels - h equal to 30 mm;
• titanium - any thickness.

1. Nitrogen with hydrogen. Used for cutting:

• copper and its alloys of medium thickness (up to 100 mm);
• aluminum and alloys of medium thickness – up to 100 mm.

Nitrogen mixture is not suitable for cutting any steel or titanium.

1. Argon with hydrogen. Used for cutting:

• Copper, aluminum and alloys based on them with a thickness of 100 mm and above;
• High-alloy steel up to 100 mm thick.

It is not recommended to use argon with hydrogen for cutting carbon, low-carbon and low-alloy steels, as well as titanium.

Equipment for plasma cutting: types and brief characteristics.

To mechanize plasma cutting, semi-automatic and portable machines of various modifications have been created.

1. can work with both active and inactive gases. The thickness of the cut material ranges from 60 to 120 mm.

• Gas consumption:

1. air – from 2 to 5 m3/hour;
2. argon – 3 m3/hour;
3. hydrogen – 1 m3/hour;
4. nitrogen – 6 m3/hour.

• Travel speed – from 0.04 to 4 m/min.
• Operating gas pressure – up to 0.03 MPa.
• The weight of semi-automatic machines is 1.785 - 0.9 kg, depending on the modification.

2. Portable machines use compressed air.

• The thickness of the material to be cut is no more than 40 mm.
• Compressed air consumption – from 6 to 50 m3/hour;
• Cooling of plasma torches – with water or air.
• Travel speed – from 0.05 to 4 m/min.
• Operating gas pressure – up to 0.4 – 0.6 MPa.
• The weight of portable machines is up to 1.8 kg, depending on the modification.
• Water-cooled plasma torches can only be operated at positive temperatures environment.
• Semi-automatic and portable machines are suitable for industrial use.

For manual cutting, two sets are available:

• KDP-1 with plasma torch RDP-1;
• KDP-2 with plasmatron RDP-2.

The KDP-1 device is used for cutting aluminum (up to 80 mm), stainless and high-alloy steels (up to 60 mm) and copper (up to 30 mm).

Maximum operating current – ​​400 A.

Maximum voltage idle move power source – 180 V.

The RDP-1 plasma torch operates with nitrogen, argon or a mixture of these gases with hydrogen.

The RDP-1 plasma torch is cooled with water, so it can be used at temperatures above 0 degrees Celsius.

The KDP-2 device is inferior to the first in terms of arc power (only 30 kW). The advantage of this model is that the RDP-2 plasma torch is cooled by air. As a result, the kit can be used on outdoors at any ambient temperature.

Complete set of manual cutting devices:

• cutting plasma torch;
• cable-hose package;
• collector;
• lighter to excite the cutting arc.

Kits for manual plasma cutting are produced without remote control. This design solution is rational for performing a limited amount of work with equipment load of no more than 40 - 50%. But during operation they have to be equipped with welding rectifiers and converters.

However, we should not forget that from a safety point of view, for manual cutting, the no-load voltage of the power source is allowed to be no more than 180 V.

Do-it-yourself plasma cutting of metals: some subtleties of the process.

• The beginning of the metal cutting process is considered to be the moment of initiation of the plasma arc. Once cutting begins, it is necessary to maintain a constant distance between the plasma torch nozzle and the surface of the material. It should be from 3 to 15 mm.
• It is necessary to strive to ensure that the current is minimal during operation, because with an increase in current and air flow, the service life of the plasma torch nozzle and electrode decreases. However, the current level must ensure optimal cutting performance.
• The most difficult operation is punching holes. The difficulty lies in the possible formation of a double arc and failure of the plasma torch. Therefore, when punching, the plasma torch must be raised above the metal surface by 20 - 25 mm. The plasma torch is lowered into the working position only after the metal has been pierced through. When punching holes in thick sheets, experts recommend using protective screens with holes with a diameter of 10-20 mm. Screens are placed between the product and the plasma torch.
• For manual cutting of high-alloy steels, nitrogen is used as a plasma gas.
• When manually cutting aluminum using an argon-hydrogen mixture, the hydrogen content should not exceed 20% to increase the stability of the arc.
• Copper cutting is performed using hydrogen-containing mixtures. But brass requires nitrogen or a nitrogen-hydrogen mixture. At the same time, cutting brass occurs 20% faster than copper.
• After cutting, the copper must be cleaned to a depth of 1-1.5 mm. For brass this requirement is not mandatory.

IN Lately The use of plasma flow for cutting materials is gaining increasing popularity. The scope of use of this technology is further expanded by the appearance on the market of hand-held devices that are used to perform plasma cutting of metal.

The essence of plasma cutting

Plasma cutting involves local heating of the metal in the separation zone and its further melting. Such significant heating is achieved through the use of a plasma jet, which is formed using special equipment. The technology for producing a high-temperature plasma jet is as follows.

• Initially, an electric arc is formed, which is ignited between the electrode of the device and its nozzle or between the electrode and the metal being cut. The temperature of such an arc is 5000 degrees.
• After this, gas is supplied to the equipment nozzle, which increases the arc temperature to 20,000 degrees.
• When interacting with an electric arc, the gas is ionized, which leads to its transformation into a plasma jet, the temperature of which is already 30,000 degrees.

The resulting plasma jet is characterized by a bright glow, high electrical conductivity and exit speed from the equipment nozzle (500–1500 m/s). Such a jet locally heats and melts the metal in the processing zone, then it is cut, which is clearly visible even in a video of such a process.

IN special installations Various gases can be used to produce a plasma jet. These include:

• ordinary air;
• technical oxygen;
• nitrogen;
• hydrogen;
• argon;
• steam produced by boiling water.

Metal cutting technology using plasma involves cooling the equipment nozzle and removing particles of molten material from the processing zone. These requirements are ensured by the flow of gas or liquid supplied to the area where cutting is carried out. The characteristics of the plasma jet generated on special equipment make it possible to use it to cut metal parts whose thickness reaches 200 mm.

Plasma cutting machines are successfully used at enterprises in various industries. With their help, cutting not only metal parts, but also plastic and natural stone. Thanks to such unique capabilities and its versatility, this equipment is widely used in machine-building and shipbuilding plants, in advertising and repair enterprises, and in the public utilities sector. A huge advantage of using such installations is that they allow you to obtain a very smooth, thin and precise cut, which is an important requirement in many situations.

Plasma cutting equipment

The modern market offers devices that cut metal using plasma, of two main types:

• indirect action devices - cutting is performed in a non-contact manner;
• direct action devices - contact cutting.

The first type of equipment, in which an arc is ignited between the electrode and the torch nozzle, is used for processing non-metallic products. Such installations are mainly used in various enterprises; you will not find them in a home craftsman’s workshop or in a repairman’s garage.

In devices of the second type, an electric arc is ignited between the electrode and the part itself, which, naturally, can only be made of metal. Due to the fact that the working gas in such devices is heated and ionized throughout the entire gap (between the electrode and the part), the plasma jet in them has a higher power. This type of equipment can be used to perform manual plasma cutting.

Any plasma cutting machine operating on the contact principle consists of a standard set of components:

• power supply;
• plasma torch;
• cables and hoses used to connect the plasma torch to the power source and the working gas supply source;
• gas cylinder or compressor to obtain a jet of air at the required speed and pressure.

The main element of all similar devices is a plasma torch, it is this that distinguishes such equipment from conventional welding equipment. Plasma torches or plasma cutters consist of the following elements:

• working nozzle;
• electrode;
• an insulating element that is highly heat resistant.

The main purpose of the plasma torch is to convert the energy of the electric arc into thermal energy plasma. The gas or air-gas mixture coming out of the plasma torch nozzle through a small diameter hole passes through a cylindrical chamber in which the electrode is fixed. It is the nozzle of the plasma cutter that provides the required speed and shape of the flow of the working gas, and, accordingly, the plasma itself. All manipulations with such a cutter are performed manually by the equipment operator.

Considering the fact that the operator has to hold the plasma cutter suspended, it can be very difficult to ensure high quality metal cutting. Often, parts produced using manual plasma cutting have uneven edges, traces of sagging and jerking. In order to avoid such disadvantages, various devices are used: stands and stops, which allow for smooth movement of the plasma torch along the cutting line, as well as a constant gap between the nozzle and the surface of the part being cut.

Air or nitrogen can be used as the working and cooling gas when using manual equipment. This air-gas jet is also used to blow molten metal out of the cutting zone. When using air, it is supplied from a compressor, and nitrogen comes from a gas cylinder.

Required Power Sources

Although all plasma cutter power supplies operate on AC power, some can convert it to DC power, while others can amplify it. But those devices that operate on DC. Installations operating on alternating current, are used for cutting metals with a relatively low melting point, for example, aluminum and alloys based on it.

In cases where too high power of the plasma jet is not required, conventional inverters can be used as power sources. It is these devices, characterized by high efficiency and ensuring high stability of the electric arc, that are used to equip small industries and home workshops. Of course, it will not be possible to cut a piece of metal of considerable thickness using a plasma torch powered by an inverter, but it is optimal for solving many problems. A big advantage of inverters is their compact dimensions, which makes them easy to carry and use for work in hard-to-reach places.

Transformer-type power supplies have higher power, with the use of which both manual and mechanized cutting of metal using a plasma jet can be carried out. Such equipment is distinguished not only by high power, but also by higher reliability. They are not afraid of power surges that can damage other devices.

Any power source has such an important characteristic as on-time (ON). For transformer power supplies, the duty cycle is 100%, which means that they can be used the whole working day, without a break for cooling or rest. But, of course, such power supplies also have disadvantages, the most significant of which is their high power consumption.

How is manual plasma cutting performed?

The first thing you need to do in order to start using a machine for plasma cutting of metal is to put together all its component elements. After this, the inverter or transformer is connected to the metal workpiece and to the alternating current network.