How does a plasma cutter work - Metals and their processing

What is a plasma cutter and how does a plasma cutter for metal work?

Plasma cutting is one of the most modern effective technologies that allows you to work with metal, as well as with some materials that do not conduct current, including wood, plastic and stone.

It is not surprising that the method is in demand and is actively used in various fields of activity, in housing and communal services, in construction, and industry. The main device in the entire process is a plasma cutter, which produces an arc formed by plasma of enormous temperature.

The arc allows you to work with high precision, cutting not only along straight lines, but also to form complex shapes.

To understand the intricacies of the entire process, let’s take a closer look at the design of the device, as well as the basic principles on which its operation is based.

Design

The plasma cutter is formed by the following elements:

1. Power element , which is responsible for supplying current of one or another strength. Either transformers or inverters are used as elements.

The first option is characterized by significant mass, but is almost invulnerable to voltage fluctuations, and also makes it possible to cut metal workpieces of enormous thickness.

An inverter is a good choice if manipulations are carried out with workpieces that are not too thick. They are economical in terms of energy consumption, characterized by high efficiency and are recommended for use in private households.

2. Plasmatron . The main element through which the cutting is carried out.

The body of the part hides the electrode responsible for forming a powerful arc. The electrode is made of refractory metal, which prevents its deformation and destruction due to high temperature loads. As a rule, hafnium is used as the most durable and safe material.

At the end there is a nozzle that forms a plasma jet that easily cuts the workpiece.

The performance and power of the device is largely determined by the diameter of the nozzle. The wider the nozzle, the more air it passes per unit of time, and increasing air volumes directly increases productivity. The most common diameter is 3 millimeters.

The accuracy of the work depends on the configuration of the nozzle; for the most delicate work, an elongated element should be selected.

3. Compressor . Its main task is to pump air, without which a metal plasma cutter simply cannot function. The process is based on the use of gas to form a plasma jet and protection.

If the current of the device is limited to 200A, then simply compressed air is needed; it is enough to remove excess heat and to form a jet. This model is the optimal solution in cases where workpieces no thicker than 5 centimeters are cut.

Industrial-type installations do not use ordinary compressed air, but concentrated gas mixtures based on helium, hydrogen, and nitrogen.

4. A set of cables and hoses connects all modules to each other. Hoses transport compressed air, cables transmit electric current.

Watch a useful video, the device and how plasma cutting works:

Working principle

Now let's study directly the principle of operation of the device.

When the operator presses the ignition button, the battery supplies current to the plasmatron. This leads to the formation of a primary arc of enormous temperature, which ranges from 6 to 8 thousand degrees.

The formation of an arc between the tip of the electrode and the nozzle occurs due to the fact that it is extremely difficult to achieve this result directly between the workpiece and the electrode. Moreover, if work is carried out with a material characterized by insulating properties, this is simply impossible.

When the primary arc is formed, an air mixture is supplied to it. This air comes into contact with it, its temperature rises, and its volume increases, and the increase can even be a hundredfold. In addition to this, the air loses its dielectric properties and becomes ionized.

Due to the fact that the nozzle has a narrowing towards its end, the air flow accelerates to 2-3 meters per second and bursts out, having a temperature of almost 30 thousand degrees. Due to the high degree of ionization and enormous temperature, air is called plasma, the electrical conductivity of which is equal to this parameter of the metal being processed.

At the moment of contact with the surface being processed, the primary arc dies out, and further work is carried out due to the newly formed cutting arc. It is she who melts or burns through the material. The cut is smooth, since a powerful air flow blows away all appearing particles from the surface.

This description of how the system works is the simplest and most common.

Areas of use

Now let's look at what they can do:

Surgical cutting of large volumes of materials.
Production of sheet parts characterized by complex geometry, up to the jewelry and instrument-making industries, where maximum compliance with the original drawings is required.

Stamping is not used in such a situation, since this technology, although cheap, does not provide sufficient accuracy. The plasma cutter, despite the enormous temperature of the jet, heats the element being processed pointwise, which completely eliminates the possibility of temperature deformation.

Installation of metal structures. The plasma cutter eliminates the need for compressed oxygen and acetylene cylinders, which increases safety and convenience, especially when it comes to operations at height.
Cutting high alloy steels. Mechanical methods are not suitable in this case, since the strength of steel is enormous; a tool capable of effectively cutting sheets based on them will be very expensive and will wear out very quickly.

It turns out that the areas of use are varied. Making holes of any configuration in metal sheets, cutting pipes, angles and workpieces of other sections, processing the edges of forged products in order to “solder” the metal and close its structure - a plasma cutter is optimally suited for all this.

Basic Instructions

A few rules to help you understand how to cut effectively and safely with a plasma cutter:

It is necessary to control the location of the cathode spot; it must correspond to the center of the electrode. Such precision is achieved by vortex air supply. Deviations in the supply lead to the plasma arc shifting and losing its combustion stability. In some cases, a second arc is formed, and in the most difficult situation the device simply breaks.
Control over air flow makes it possible to adjust the plasma flow rate and vary productivity.
Cutting speed directly affects thickness. The higher the speed, the thinner the cut; decreasing it increases the width. Similar results, greater width, can be achieved by increasing the current.

Watch a video tutorial on how to use a plasma cutter:

Conclusion

So, we figured out what a plasma cutter is.

We can conclude that in a situation where you regularly have to work with metal elements, cut fittings, pipes or other parts, his help will be useful. So the costs of purchasing it will be fully offset by the convenience and efficiency of further work.

(2 5,00 out of 5)

Source: https://plavitmetall.ru/oborudovanie/plazmorez-kak-rabotaet.html

How does plasma cutting work?

In the field of metalworking, a plasma cutter is of significant importance, and we will tell you about it: what it is - air plasma cutting of metal, the principle of operation, and we will additionally show videos and photos.

What is this method

Its difference is in the cutting speed. If the classic flame is based on propane and oxygen, with a low combustion temperature. This method works on the principle of amplifying an electric arc under high pressure. As a result, the heat does not have time to be distributed throughout the workpiece, and it becomes deformed.

Feature - the arc of the plasma torch is not only a cutter. It also allows welding work if filler wire is used.

Types of plasma cutters

The peculiarity of different types is in the method of igniting the arc and maintaining it. In the classic version, it is formed between the nozzle and the part. But if the material does not have the ability to conduct current, then an ionized electric arc occurs between the cathode and anode and is maintained permanently. There are separate devices that use steam from the liquid (it is located in the tank), which increases the pressure and replaces the effect of the ionizing substance.

Types and principle of plasma cutters

Basically, the choice depends on the scope of use - what metals need to be cut, the width of the workpieces, cutting requirements, thermal conductivity of the material and other parameters. Varieties:

Tools that work in an environment of inert gases are reducing agents.
They are supplemented with oxidative vapors and are saturated with oxygen.
Technologies based on mixtures.
The work takes place in an environment of gas-liquid substances.
Water or magnetic stabilization - rarely used.

Of the above devices, the most common base is inert gases, for example, argon, hydrogen, nitrogen, helium. Depending on the thickness of the metal, devices using an inverter or transformer are used. They also differ in the presence of contact between the cutter and the workpiece or in the non-contact method.

Based on power and purpose, there are household and industrial devices. The former operate from a standard network with a voltage of 220 V, and the latter are connected to 380 V.

Plasma cutting device

Already in the name it is clear that the main element that has an effect is plasma, which consists of ionized gas under pressure with high electrical conductivity. The higher the temperature, the stronger the conductivity, and therefore the speed of the procedure. Structurally, the device consists of several parts, as shown in the diagram:

Source: https://moy-instrument.ru/masteru/kak-rabotaet-plazma-rezka.html

Plasma cutter - device, principle of operation, choice, which is better

What is a plasma cutter and how does it work? If we talk about this tool, it should be noted that it is a device that is used by a fairly narrow circle of welders. For one-time use, a plasma cutter is never used anywhere. Because there are tools with which you can carry out cutting operations without resorting to an expensive option, for example, a grinder.

But if the requirements for the speed and volume of the processes carried out are quite strict, then you cannot do without a plasma cutter. Therefore, it is used in the engineering industry, in the manufacture of large metal structures, when cutting pipes and other things.

Types of plasma cutters and their purpose

The answer to the question of how to choose a plasma cutter is that everything will depend on the area in which you are going to use it. Because the design features of different types are very different, they all have a different type of arc ignition and different power of the cooling system.

Instruments operating in protective gases: argon, hydrogen, nitrogen, helium and so on. These gases have reducing properties.
Cutters operating in oxidizing gases. Gases are usually saturated with oxygen.
Devices that work with mixtures.
Plasma cutters operating in gas-liquid stabilizers.
Plasma cutters working with water and magnetic stabilization. A specific tool that is rarely used and therefore difficult to find on the open market.

There is another classification that divides plasma cutters according to the type of equipment used.

Inverter. An economical option that can cut metal parts up to 30 mm thick.
Transformer. Performs cutting of metals up to 80 mm thick, a less economical option.

Based on the type of contact, plasma cutters are divided into contact and non-contact. From the names you can understand the method of using a plasma cutter. In the first case, it requires contact with the metal being processed, so it can be used to cut products with a thickness of no more than 18 mm. In the second, there should be no such contact, but the thickness of the cut metal workpiece can be the maximum possible.

And another type of division is based on the type of use and possibilities of electricity consumption. There are two positions here: household, operating from an alternating current network with a voltage of 220 volts, and industrial (professional), connected to a three-phase power supply network with a voltage of 380 volts.

Attention! Even the lowest-power household plasma cutter has a power of 4 kW. Therefore, when connecting it to a household electrical network, you need to make sure that it can withstand such a load.

But this load is not the only one. The plasma cutting system uses cooling, for which a compressor is included with the main equipment, which also operates from the mains. And its power must be taken into account when connecting to a household power supply.

Plasma cutter device

The name itself already informs that metal cutting is done using plasma. And plasma is an ionized gas that has a high conductivity of electric current. And the higher the temperature of this gas, the higher the conductivity, which means the cutting force increases.

For metal cutting processes, an air-plasma arc is used. In this case, the electric current has a direct effect on metal surfaces. That is, the principle of operation of a plasma cutter is as follows:

Metal melting.
Blowing its liquid state out of the cut area.

The plasma cutter consists of:

power source - this can be a welding transformer or inverter;
the cutter itself, which is sometimes called a plasma torch;
compressor;
hoses.

It is important to understand the design features of the cutter itself. An electrode made of rare metals such as beryllium, hafnium, zirconium and so on is inserted inside it.

Why them? Because during the heating process, refractory oxides are formed on the surface of such an electrode. They are a kind of protection for the electrode itself, which ensures the integrity of the material, that is, it does not collapse.

But most often, plasma cutters use hafnium electrodes because it is non-toxic like thorium and non-radioactive like beryllium.

The nozzle through which plasma is supplied for cutting also plays an important role in the design of the cutter. The main characteristics of the equipment depend on it. Or rather, on its diameter and length.

The power of the plasma flow depends on the diameter, and, accordingly, the speed of cutting and the width of the cut groove. Of course, the cooling rate of the workpiece also depends on this. Most often, plasma cutting torches are equipped with a nozzle with a diameter of 3 mm. The length of the nozzle affects the quality of the cut.

The longer it is, the higher the quality. Although a very long nozzle quickly fails.

Plasma cutting operation diagram

When you press the ignition button, the power source automatically turns on, which supplies high-frequency current to the cutter. A so-called pilot arc appears between the nozzle tip and the electrode. Arc temperature – 6000-8000С. It is necessary to pay attention that an arc does not form immediately between the electrode and the metal being cut; this takes time.

After which air from the compressor begins to flow into the cutter chamber; it is compressed. When passing through the chamber where the pilot arc is located, the air heats up and increases in size a hundred times. In addition, it begins to ionize, that is, it turns into a conductive medium, although air itself is a dielectric.

The nozzle, narrowed to 3 mm, creates a plasma stream that flies out of the cutter at high speed. Speed – 2-3 m/s. The temperature of ionized air reaches enormous values - up to 30,000C. At this temperature, the air conductivity of electric current approaches the conductivity of metal.

As soon as the plasma touches the metal surface being processed, the pilot arc is turned off and the working arc is turned on. The metal workpiece is melted at the cut site, from where the liquid metal is blown away by air supplied to the cut zone. Here is an elementary diagram of the operating principle of plasma cutting.

How to choose the right plasma cutting tool

Any welder who has worked with plasma cutting will note that the higher the current applied to the electrode, the faster the process. But there are certain conditions that are affected by other equipment parameters.

Type of metal and cut thickness. The choice of equipment to work with will depend on these parameters. Namely, such a parameter as current strength. Below is a table of ratios.

Type of metalCurrent strength for cutting a metal sheet 1 mm thick, A

Non-ferrous metals	6
Ferrous metals and stainless steel	4

To cut a copper sheet 2 mm thick, you will need a plasma cutter with a current of 12 A. And so on.

Attention! It is recommended to purchase equipment with a reserve current. Because the parameters indicated in the table are maximum, and you can only work with them for a short time.

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Advantages and disadvantages

Before deciding to purchase a plasma cutter, you need to familiarize yourself with all the positive and negative aspects of this equipment. After all, for example, at home it can be replaced by an ordinary grinder.

So, the advantages of using a cutter for plasma cutting of metals.

High cutting speed, correspondingly reducing the time for this process. Compared to other cutting tools (oxygen torch, for example), the speed is six times higher. Second only to laser cutting.
Using a plasma tool, you can cut thick workpieces, which is sometimes beyond the power of an angle grinder.
Cuts all types of metals. The main thing is to set the operating mode correctly.
Minimum preparatory stage. There is no point in cleaning the surfaces of parts from rust, dirt, and oil stains. They are not a hindrance for cutting.
Highest cutting precision and high quality. For manual units, for cutting accuracy, special stops are used that prevent the cutter from moving in the plane. The cut is smooth, smooth and thin.
Low heating temperature, except for the cut zone, so the workpieces are not deformed.
Possibility of curved cutting. And although other cutting tools can boast of this, for example, after using an oxygen torch, you will have to grind the edges of the cut and remove metal stains.
One hundred percent safety of the operations carried out, because there are no gas cylinders in the equipment set.

Minuses:

High price of equipment.
Ability to work with only one cutter.
It is necessary to maintain the direction of the plasma strictly perpendicular to the plane of the workpiece. True, today you can buy devices that cut products at different angles: 15-50°.
The thickness of the cut product is limited, because the most powerful plasma cutters can cut metal 100 mm thick. Using an oxygen torch, you can cut a thickness of 500 mm.

And yet plasma cutters are quite in demand today. Manual ones are often used in small shops where a large volume of metal cutting is required, and where strict requirements are imposed on the quality of the cut. Be sure to watch the video that is specially posted on this page of the site.

Source: https://svarkalegko.com/oborudovanie/plazmorez.html

Plasma cutting of metal: types and principle of operation, design of a plasma torch, video of plasma cutting technology - SibNovStroy

In the very recent past, in order to cut metal, one had to resort to completely inconvenient, bulky gas-powered devices.

However, such cutters could not always cope with the task.

Today, both small enterprises and industrial facilities widely use plasma cutting, with which it is possible to process metal of any configuration and thickness as accurately as possible.

Operating principle of plasma cutting

Plasma cutting is a separation treatment of metal using a thermal process. The role of the cutting tool here is played by a jet of low-temperature plasma.

Operating principle of the plasma device:

An electric arc with a temperature of 5000C is created between the metal being cut and the electrode or nozzle of the plasma torch.
Gas enters the nozzle under pressure, due to which the temperature of the electric arc rises to 20,000C.
The gas is ionized and converted into high temperature gas or low temperature plasma.
Ionization increases from the heated arc, and the temperature of the gas jet rises to 30,000C. During this process, the plasma stream has high thermal conductivity and glows brightly.
Plasma flows from the nozzle at a speed of 500–1500 m/s, hits the prepared metal, heats it up and melts it at the cut site.

The process of cutting metal using a plasma torch can be seen more clearly in the video.

Types of plasma cutting

Plasma cutting of metal comes in several types:

Simple. This method uses electric current and air.
The length of the electric arc during such a process is limited, therefore, with a sheet thickness of several millimeters, surface treatment is compared to laser cutting.

The simple method is used for processing only mild or low-alloy steel. When cutting the material, burrs are not formed, the edge remains smooth. Sometimes nitrogen can be used instead of air.
Using water . During cutting, water is used to cool the plasma torch and protect the cut from the negative influence of the environment. In addition, all harmful fumes are absorbed by water.
Using protective plasma gas . The cut during such cutting is protected from the environment, so the quality of metal cutting increases.

You can also cut metal using an arc or a jet. In the first case, the material being processed is part of the circuit, in the second, an arc is formed between the electrodes.

Device for plasma cutting of metals

The main element of the equipment is a plasma cutter, which is called a plasma torch. Its main components:

Electrode , which is located at the back of the chamber. It forms an electric arc.
The nozzle is responsible for the shape of the plasma flow and its speed.
A heat-resistant insulator is located between the nozzle and the electrode.

In addition to the plasmatron, the metal cutting device is equipped with:

compressor or gas cylinder;
power supply;
a set of hoses or cables designed to connect the plasmatron to the compressor and power source.

Since you have to work with the device in weight, the cut may turn out uneven. Therefore, to improve the quality of cutting, it is recommended to use stands or special stops that are placed on the nozzle.

Source: https://sibnovostroy.ru/stanki/plazmennaya-rezka-metalla-vidy-i-printsip-dejstviya-ustrojstvo-plazmotrona-video-tehnologii-rezki-plazmoj.html

Plasma cutter: nuances of choice + 5 best models - Do-it-yourself apartment renovation: renovation school for beginners and more

A plasma cutter is not often needed on the farm, but people who constantly work with metal sometimes need it. This device allows you to cut metal much faster and easier than using a grinder. Therefore, in this article I want to share with you some nuances that you need to know when choosing a plasma cutting machine.

The device allows you to quickly and effortlessly cut thick metal workpieces

Device structure

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

Plasma cutter elements

Next, we will consider in detail the device of the plasma cutter.

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;

Diagram of the direct action plasma torch

Indirect. The arc discharge occurs inside the plasma torch itself. This allows the device 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. Therefore, the best option is when the length of the nozzle is one and a half times greater than its width;

Diagram of the nozzle and electrode

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

Source: https://kursremonta.ru/remontnye-raboty/plazmorez-807

Plasma cutter: principle of operation, device, instructions for use +

Plasma cutter: operating principle, device, instructions for use

What is a plasma cutter and on what principle does it work? If we talk about this tool, then it’s worth noting right away that this is the device that welders use, and not all of them. For one-time use, such a tool is never used anywhere.

For this reason, there are tools with which it is possible to carry out cutting operations, and without resorting to using an expensive option, namely an angle grinder.

But if the requirements for the volume and speed of the process are stricter, then you cannot do without using a plasma cutter.

It is for this reason that it is used in the engineering industry, in the manufacture of large metal structures, for cutting pipes and everything else.

Types of cutters and the purpose of each of them

A lot when choosing a plasma cutter will depend on what area you plan to use it for. The fact is that the design features of all types are very different from each other - each device has its own type of arc ignition, as well as the power of the cooling system.

Instruments that operate in protective gases – hydrogen, argon, helium, nitrogen and others. Such gases have reducing properties.
Cutters that operate in an environment of oxidation gases. Such things are usually saturated with oxygen.
Devices used for working with mixtures.
Cutters that work in liquid-gas stabilizers.
Devices that work with magnetic and water stabilization. This is a special tool that is very rarely used, so it is quite difficult to find on the open market.

There is another classification that helps you divide and buy a plasma cutter according to the type of equipment that is used for the work.

Inverter - an option recognized as economical, can handle metal parts with a thickness of up to 3 cm.
Transformer - such devices are capable of cutting metal with a thickness of up to 8 cm, the option itself is less economical.

Based on the type of contact, devices can be divided into two groups - contactless and contact. By the name it is already easy to understand what methods of using a plasma cutter are available. In the first case, the device does not require contact with the metal being processed, and the thickness of the workpiece can be any, while in the second case, contact with the metal is required, and its thickness must be at least 1.8 cm.

Another category is the type of use and the ability to be powered by electrical energy. in this case, there are two positions - a household cutter, which operates from an alternating current network and a standard voltage of 220 V, and an industrial one, which can only be connected to a three-phase power supply with a voltage of 380 V.

Please note that even those cutters that have a minimum power will be from 4 kW. For this reason, when connecting it to a household electrical outlet, first make sure that it can definitely withstand such a load.

This load is not the only one, since in the plasma cutting system the device uses cooling, and for this purpose the standard equipment comes with a compressor, which will also operate from the mains. Take into account its power when connecting to home power.

Device

The name itself already makes it clear that the process of cutting metal is carried out thanks to plasma, the latter being an ionized gas with high electrical conductivity. The higher the gas temperature, the higher the conductivity will be, and the cutting force will increase significantly. An air-plasma arc is also used for the metal cutting process. Please note that in this case the current will already have a direct effect on the metal surface.

It turns out that the principle of operation of the device is as follows:

The metal is melted.
Its liquid state is blown out of the cut area.

A manual plasma cutter consists of:

Power supply - this can be an inverter or a welding transformer.
Hoses.
A cutter, which is sometimes called a plasma torch.
Compressor.

It will not be superfluous to understand the design features of the cutter. Inside the device there is an installed electrode, which is made of rare metal, for example, hafnium, beryllium, zirconium and others.

Why these metals? The fact is that when heated, refractory types of oxides are formed on the surface of this electrode. They are a kind of protection for the electrode, which will ensure the integrity of the material, i.e. do not destroy.

Most often, hafnium electrodes are installed in plasma cutters, because this metal is not toxic and radioactive, like, for example, beryllium.

The nozzle plays an important role in the design - it is through it that the plasma enters the cutting. It is on this that the main parameters of the device will depend, or more precisely on the thickness and length of the nozzle.

T diameter will depend on the power of the plasma flow, and hence the cutting speed and width of the cut groove. Of course, the cooling rate will also depend on this. Most often, a nozzle with a diameter of 0.3 cm is installed on cutters.

The length will be directly proportional to the quality of the cut - the longer, the better. Please note that a very long nozzle will quickly fail.

Plasma cutter operation diagram

So, when you press the ignition button, the electrical power source automatically turns on and high-frequency current flows into the cutter. Because of this, a pilot arc appears between the electrode and the nozzle tip. The arc temperature ranges from +6,000 to +8,000 degrees. It should be noted that the arc between the metal being cut and the electrode does not appear immediately; it takes time.

After this, the air that was in the compressor (compressed) begins to flow into the cutter chamber. The air begins to heat up as it passes through the chamber in which the pilot arc is located, and it becomes 100 times larger. In addition, it begins to ionize, essentially turning into a conductive medium, although air itself is a dielectric.

A nozzle that is narrowed to 0.3 cm creates a plasma stream that flies out of the cutter at high speed (2 to 3 meters per second). The temperature of the air, which has become ionized, reaches up to +30,000 degrees.

At this temperature, the conductivity of the air becomes the same as the conductivity of the metal. As soon as the plasma hits the surface being treated, the pilot arc turns off, but the working arc turns on instead.

Melting of the metal workpiece is carried out at the cut site, from where the liquid metal is blown away by air, which enters the cut zone. This is the cutting diagram.

Tool selection rules

People who have worked with a plasma cutter will note that the greater the current entering the electrode, the faster the process will be. But there are some conditions that will be affected by other equipment parameters. This includes the thickness of the cut and the type of metal. Such parameters will determine which equipment to choose for work, namely such parameters as current strength. To cut a sheet of copper with a thickness of 0.2 cm, you will need a plasma cutter with a current of 12 A.

Please note, we advise you to buy equipment that will have a reserve current. Usually the specified parameters when purchasing are maximum, which means that you can work on them for a short time.

Advantages and disadvantages

Before you make a choice and decide whether to buy a plasma cutter or not, you should learn about all the negative and positive aspects of the equipment. So, for example, at home this device can be replaced with an angle grinder.

So, the advantages are as follows:

Cutting at high speed, which means not much time will be spent on the process. Compared to other cutting tools (for example, an oxygen torch), the speed is as much as 6 times higher. It is second only to laser cutting.
Using a plasma device, you can cut workpieces with a large thickness, and this is not always possible even for an angle grinder.
It can cut any type of metal, the main thing is that the operating mode is set correctly.
The minimum stage of preparation - the surfaces of the parts can be cleaned from dirt, rust, oil stains, but there is no point in this, since this is not an obstacle to cutting.
The cutting accuracy is high, and so is the quality. For manual devices, to improve cutting accuracy, special stops are often used that will prevent the cutter from moving along the plane. The result is a cut without sagging, thin and even.
The heating temperature is low, with the exception of the cut zone, so the workpieces are not subject to deformation.
The ability to make a shaped cut, and although other tools can boast of this quality, for example, after using an oxygen torch, you will have to grind the edges of the cut and remove metal stains.
The operation performed is 100% safe, since there is not a single gas cylinder included with the equipment.

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Flaws:

High cost of equipment.
It is permissible to work with only one cutter.
The direction of the plasma should be maintained exactly perpendicular to the plane of the workpiece. At the moment, devices have appeared on sale that can cut at an angle from 15 to 50 degrees.
The thickness of the product for cutting is limited, so the most powerful specimens can cut metal 10 cm thick. Using an oxygen torch, you can cut metal 50 cm thick.

And, nevertheless, the plasma cutter as a device is quite in demand. Manual types are often used, but only in small enterprises where large volumes of cutting need to be performed and strict requirements are imposed on the quality of the cut.

Source: https://domsdelat.ru/instrumenty/plazmorez-princip-dejstviya-ustrojstvo-instrukciya-po-primeneniyu.html

The principle of operation of a plasma torch: features of cutting metal with a plasma torch

The history of the plasma torch dates back to the middle of the last century. The production of refractory metals, which was gaining momentum at that time, required special processing technology. Another factor that led to the launch of the devices was the need for a powerful source of light and heat. To answer the question of which plasma torch is better, you should first understand the features of this technical device and consider its varieties.

Plasmatron: general features

A plasma torch is a special technical device through which electric current is converted into plasma, and the latter is used for cutting metal materials of different thicknesses.

Features of modern devices include:

the ability to obtain high temperatures that cannot be achieved with conventional fuel;
ease of control and adjustment (setting start, stop and power);
high degree of reliability and compact dimensions.

Device elements

The plasma torch device is designed in such a way as to ensure cutting of metals belonging to the refractory class. The electrode (cathode) has a special zirconium or hafnium insert. The use of these metals at high temperatures makes it possible to achieve the effect of knocking out electrons from their surface (thermionic emission).

The nozzle is another consumable element of the plasmatron, which is always isolated from the cathode. The device is also equipped with a mechanism for swirling gas to form plasma.

The consumables are capable of functioning during one 8-hour work shift when we are talking about processing metal up to 1 cm thick. Then they must be replaced, and it is advisable to carry out the latter simultaneously for the cathode and nozzle.

If replacement deadlines are not met, the quality of the resulting cut will deteriorate significantly; waves may appear or the effect of cutting at an angle may be felt. If the hafnium or zirconium insert burns out more than 2 mm, the electrode will burn. The result will be significant overheating of the device.

To prevent the molten material being processed from damaging the elements of the plasma torch, it is equipped with a protective casing. Regular dismantling and cleaning of the casing is the key to long and high-quality operation of the entire device. If basic operating conditions are not observed, you can soon cause serious damage to the plasma cutter. It is equally important to clean other elements.

Types of plasmatrons

The entire range of modern technical devices for cutting metals can be divided into three classes:

electric arc plasmatrons;
high-frequency plasma cutters;
combined devices.

To understand the operating features of each type of plasma torch from the designated classes, you should consider them separately.

Electric arc plasma torches

All devices of this class are equipped with an anode and cathode, which are connected to a direct current source. The role of the refrigerant is performed by ordinary water circulating through special channels. On the market you can find devices with an electrolytic electrode. The latter can also rotate.

High frequency plasma cutters

A feature of devices of this class is the absence of electrodes, since communication with the power source is carried out thanks to the inductive (or capacitive) principle. Accordingly, plasmatrons are divided into induction and capacitive.

The operating principle of plasma torches, which belong to the class of high-frequency devices, implies that the chamber where the discharge occurs is made of non-conducting materials. Glass or ceramics are often used.

The walls are insulated according to the gas-dynamic principle, so the devices are protected from overheating and can be cooled by air.

Combination devices

The devices combine the operation of an arc discharge (its combustion) and the operation of high-frequency currents. Moreover, in some devices the arc discharge is additionally compressed due to an external magnetic field. In addition to the indicated division, devices are divided into types according to the method of their cooling, the method of stabilizing the electric arc, etc.

Plasma cutting of metals: top three

The criteria for determining the best manufacturers of plasma torches are: the reliability of the device, its cost and weight, as well as functionality.

Svarog CUT 40B (R34) is an excellent combination of device cost and power performance. The average market price is 28 thousand rubles. The device is compact in size and light in weight. Optimal for cutting thin sheet metal.

An ergonomic control panel combined with a connector for connecting a torch makes working with the device comfortable and simple. The disadvantage is the limited working resource.

Aurora Pro AirForce 60 IGBT has proven itself to be the most energy-saving device. The price is about 40 thousand rubles. Copes with cutting mild steel, aluminum, copper. Thanks to a cutting current of 60 A, the device is able to cope with 20 mm steel. The disadvantage is poor adaptability to the conditions of industrial continuous use.

Brima CUT 120 is ideal for working with thick materials. The device costs about 90 thousand rubles. If you look at the photo of the plasma torch, the small size of the transformer immediately catches your eye. This results in the low weight of the device. The thickness of the metal being processed can reach up to 35 mm. The main disadvantage is sensitivity to humid environments.

Photo of the plasma torch in operation

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Source: https://instrumentgid.ru/princip-raboty-plazmotrona_/

How plasma cutting works: technology, capabilities, advantages

Issues discussed in the material:

What is plasma, plasma cutter, plasmatron
How does plasma cutting of metal occur?
What gases are used in plasma cutting?
What can be cut with plasma
What types of plasma cutting machines are there?
What are the advantages of plasma metal cutting

Today, many are interested in how plasma cutting works and how the technology differs from traditional methods of processing metal and other materials. Ordinary people and even some experts doubt the need to use plasma, believing that any welding work can still be performed using traditional gas.

In this material we will try to explain in an accessible language what a plasma cutter is, how it works, and what its advantages are over laser and gas welding. After this, you are unlikely to have any doubts about the effectiveness of cutting metal using plasma.

Plasma cutting - what is it?

Metal cutting is a technological process of dividing a monolithic element into parts. For this purpose, a mechanical method can be used, that is, chopping or sawing, waterjet, where processing is carried out using a suspension of water and abrasive, as well as a thermal method or heating. Heat treatment refers to oxygen gas, laser and plasma cutting of metal.

What is plasma cutting? This is a technology for processing metal products, in which a plasma jet plays the role of a cutter.

Plasma is a stream of ionized gas heated to a temperature of several thousand degrees. Such a flow contains negatively and positively charged particles. It has quasi-neutral properties, that is, in an infinitesimal volume, the total charge is balanced and turns out to be zero. However, due to the presence of free radicals, plasma is capable of conducting electricity.

Due to the combination of plasma properties such as high temperature, the ability to conduct electricity and flow speeds exceeding the speed of sound, a device for plasma cutting was developed in the 20th century.

If we talk more simply about how plasma cutting works, then we are talking about heating the metal with a plasma jet using a plasma cutter. This device creates an electric arc between the cutter nozzle and the metal being processed, the temperature of which reaches +5,000 °C. However, effective processing with such heating is impossible. To achieve high-quality results, gas is additionally supplied to the working area - it is this gas that forms plasma with temperatures up to +30,000 °C.

In addition to the fact that the plasma is very hot, it exits the nozzle at a speed of 1,500 m/s, making it possible to easily cut metal. It is worth noting that such processing is characterized by high precision and accuracy, so modern industry is increasingly giving preference to it.

How does plasma metal cutting work?

How does a plasma cutting machine work? The electric arc is intensified by acceleration with gas under pressure, due to which the temperature of the cutting element increases several times compared to a propane-oxygen flame. This makes it possible to quickly cut metal in such a way that even with high thermal conductivity, the entire product does not have time to heat up and become deformed.

So how does plasma metal cutting work? The essence of the method is as follows:

Source: https://vt-metall.ru/articles/366-kak-rabotaet-plazmennaya-rezka

Plasma torch: operating principle and design

A plasma torch is a plasma generator, that is, a technical device in which electric current is used to generate plasma, which, in turn, is used for the purpose of processing materials, for example, for cutting with a plasma torch.

The first plasmatrons appeared in the mid-twentieth century, which was caused by the expansion of the production of refractory metals and the need to introduce technology for processing materials that are resistant to high temperatures. Another reason for the appearance of plasmatrons is the need for a heat source of increased power.

We invite you to see how a manual plasma torch (also known as a plasma cutter) works:

Here are the main features of modern plasmatrons :

Obtaining ultra-high temperatures unattainable when using chemical fuels
Ease of power regulation, starting and stopping the operating mode
Compact and reliable device

Plasma torch device

The design of a plasma torch for cutting metal is represented by the following structural elements:

Electrode/cathode with an insert made of zirconium or hafnium - metals with high thermionic emission
Plasmatron nozzle, usually isolated from the cathode
Mechanism for swirling plasma-forming gas

Nozzles and cathodes are the main consumables of plasma torches. When the thickness of the metal being processed is up to 10 mm, one set of consumables is enough for one work shift – eight hours of work. The nozzles and cathodes of plasma torches, as a rule, wear out at the same rate, so their replacement can be organized at the same time.

Untimely replacement of consumables can have a great impact on the quality of the cut: for example, if the geometry of the nozzle is violated, the effect of an oblique cut may occur, or waves will appear on the cut surface.

The wear of the cathode is expressed in the gradual burnout of the hafnium insert, the production of which in a volume of more than 2 mm contributes to the burning of the cathode and overheating of the plasma torch.

Thus, untimely replacement of worn-out consumables entails faster wear of the remaining plasma torch components.

To protect the plasma torch from splashes of molten metal and metal dust during operation, a special casing is put on it, which must be removed from time to time and cleaned of contaminants. Failure to use a protective casing leads to the risk of a negative impact of the above contaminants on the quality of operation of the plasma torch and even to its breakdown. In addition to cleaning the casing, it is worth cleaning the plasma torch itself from time to time.

You can learn more about plasma cutting technology by watching the following video:

Types of plasmatrons for cutting metals

All existing plasmatrons are divided into three large groups:

I. Electric arc

II. High frequency

III. Combined

Electric arc plasma torches are equipped with at least one anode and cathode connected to the DC plasma torch power source. The coolant used in such devices is water, which circulates in the cooling channels.

There are the following types of electric arc plasma torches:

Straight arc plasma torches
Plasma torches with indirect arc (indirect plasma torches)
Plasmatrons using an electrolytic electrode
Plasma torches with rotating electrodes
Plasma torches with rotating arc

High-frequency plasma torches have neither electrodes nor cathodes, because the inductive/capacitive principle is used to connect such a plasma torch to the power source. It follows from this that high-frequency plasmatrons are divided into induction and capacitive.

The operating principle of high-frequency plasma torches requires that the discharge chamber of such devices be made of non-conducting materials, and ceramics or quartz glass are usually used as such.

Since maintaining an electrodeless discharge does not require electrical contact of the plasma with the electrodes, plasmatrons of this type use gas-dynamic insulation of the walls from the plasma jet, which makes it possible to avoid their overheating and limit themselves to air cooling.

Combined plasmatrons operate under the combined action of high-frequency currents and the combustion of an arc discharge, including its compression by a magnetic field.

In addition to the general classification of plasma torches into electric-arc, high-frequency and combined, such devices can be divided into groups according to many principles: for example, depending on the type of cooling, according to the method of arc stabilization, depending on the type of electrodes or current used.

Arc stabilization system during plasmatron operation

Depending on the method of arc stabilization, all plasmatrons are divided into gas, water and magnetic. It must be said that the arc stabilization system is very important for the functioning of the plasma torch, because it is it that ensures compression of the column and its fixation along the axis of the electrode and nozzle.

The simplest and most common arc stabilization system is gas. Its operating principle is to cool and compress the walls of the arc column with an external, colder plasma-forming gas. The water system makes it possible to achieve a higher degree of compression and raise the temperature of the arc column to 50,000 degrees.

Plasmatrons of this type use a graphite electrode, which is fed to the extent of its combustion, since water vapor near the electrode provides an increased rate of this process. Compared to these two stabilization systems, magnetic arc stabilization is considered less effective, but its advantage is the ability to adjust the degree of compression without loss of plasma gas.

Source: https://plasmainfo.ru/technology/416/

Making a plasma cutter from an inverter with your own hands: instructions, diagrams, video

Factory plasma cutting machine. Our task: to make an analogue with your own hands

Making a functional plasma cutter with your own hands from a serial welding inverter is not as difficult as it might seem at first glance. In order to solve this problem, it is necessary to prepare all the structural elements of such a device:

plasma cutter (also called a plasma torch);
a welding inverter or transformer that will act as a source of electric current;
a compressor, with the help of which a jet of air will be created, necessary for the formation and cooling of the plasma flow;
cables and hoses for combining all structural elements of the device into one system.

General scheme of plasma cutting operation

Plasma cutters, including homemade ones, are successfully used to perform various jobs both in production and at home. Such a device is indispensable in situations where it is necessary to perform an accurate, thin and high-quality cut of metal workpieces. Some models of plasma cutters, due to their functionality, allow them to be used as a welding machine. This welding is performed in an argon shielding gas environment.

Gas hose and return cable for plasma cutting

When choosing a power source to complete a homemade plasma torch, it is important to pay attention to the current strength that such a source can generate.

Most often, an inverter is chosen for this, providing high stability to the plasma cutting process and allowing for more economical energy consumption. Differing from a welding transformer in its compact dimensions and light weight, the inverter is more convenient to use.

The only disadvantage of using inverter plasma cutters is the difficulty of cutting too thick workpieces with their help.

ABIPLAS plasma cutter torch and its components

When assembling a homemade device for performing plasma cutting, you can use ready-made diagrams that are easy to find on the Internet. In addition, there is a video on the Internet on how to make a plasma cutter with your own hands. When using a ready-made diagram when assembling such a device, it is very important to strictly adhere to it, and also pay special attention to the correspondence of the structural elements to each other.

Schemes of a plasma cutter using the example of the APR-91 device

When considering the electrical circuit diagram, we will use the APR-91 plasma cutting machine as a donor.

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Power section diagram (click to enlarge)

Plasma cutter control circuit (click to enlarge)

Oscillator circuit (click to enlarge)

Elements of a homemade plasma cutting machine

The first thing you need to find to make a homemade plasma cutter is a power source in which an electric current with the required characteristics will be generated. Most often, inverter welding machines are used in this capacity, which is explained by a number of their advantages.

Due to its technical characteristics, such equipment provides high stability of the generated voltage, which has a positive effect on the quality of cutting.

Working with inverters is much more convenient, which is explained not only by their compact dimensions and low weight, but also by ease of setup and operation.

Operating principle of a plasma cutter

Due to their compactness and light weight, plasma cutters based on inverters can be used to perform work even in the most inaccessible places, which is impossible for bulky and heavy welding transformers. A huge advantage of inverter power supplies is that they have high efficiency. This makes them very energy efficient devices.

In some cases, a welding transformer can serve as a power source for a plasma cutter, but its use is fraught with significant energy consumption. It should also be taken into account that any welding transformer is characterized by large dimensions and significant weight.

The main element of the apparatus designed for cutting metal using a plasma jet is a plasma cutter. It is this element of equipment that ensures the quality of cutting, as well as the efficiency of its implementation.

The shape and size of the plasma jet depends on the nozzle diameter

To form an air flow that will be converted into a high-temperature plasma jet, a special compressor is used in the design of the plasma cutter. Electric current from the inverter and air flow from the compressor are supplied to the plasma cutter using a cable and hose package.

The central working element of the plasma cutter is the plasma torch, the design of which consists of the following elements:

nozzles;
the channel through which the air stream is supplied;
electrode;
an insulator that simultaneously performs a cooling function.

Design of a plasma cutter and recommendations for its manufacture

The first thing that needs to be done before manufacturing a plasma torch is to select the appropriate electrode for it. The most common materials used to make electrodes for plasma cutting are beryllium, thorium, zirconium and hafnium. When heated, refractory oxide films are formed on the surface of these materials, which prevent the active destruction of the electrodes.

Replacement nozzles for plasmatron

Some of the above materials, when heated, can emit compounds hazardous to human health, which should be taken into account when choosing the type of electrode. Thus, when beryllium is used, radioactive oxides are formed, and thorium vapors, when combined with oxygen, form dangerous toxic substances. The completely safe material from which electrodes for plasmatrons are made is hafnium.

The nozzle is responsible for the formation of the plasma jet, thanks to which cutting is performed. Its manufacture should be given serious attention, since the quality of the work flow depends on the characteristics of this element.

Plasma torch nozzle structure

The most optimal is a nozzle with a diameter of 30 mm. The accuracy and quality of the cut depends on the length of this element. However, you should also not make the nozzle too long, since this contributes to its destruction too quickly.

As mentioned above, the design of a plasma cutter necessarily includes a compressor that forms and supplies an air flow to the nozzle. The latter is necessary not only for the formation of a jet of high-temperature plasma, but also for cooling the elements of the apparatus. The use of compressed air as a working and cooling medium, as well as an inverter that generates an operating current of 200 A, allows you to effectively cut metal parts whose thickness does not exceed 50 mm.

Choosing gas for plasma cutting of metal

In order to prepare the plasma cutting machine for operation, it is necessary to connect the plasma torch with an inverter and an air compressor. To solve this problem, a cable-hose package is used, which is used as follows.

The cable through which electric current will be supplied connects the inverter and the plasma cutter electrode.
A hose for supplying compressed air connects the compressor outlet and the plasmatron, in which a plasma jet will be formed from the incoming air flow.

Features of the plasma cutter

To make a plasma cutter using an inverter for its manufacture, you need to understand how such a device works.

After turning on the inverter, electric current from it begins to flow to the electrode, which leads to the ignition of an electric arc. The temperature of the arc burning between the working electrode and the metal tip of the nozzle is about 6000–8000 degrees.

After the arc is ignited, compressed air is supplied to the nozzle chamber, which passes strictly through an electric discharge. The electric arc heats and ionizes the air flow passing through it.

As a result, its volume increases hundreds of times, and it becomes capable of conducting electric current.

Using a plasma cutter nozzle, a plasma jet is formed from a conductive air flow, the temperature of which actively increases and can reach 25–30 thousand degrees.

The speed of the plasma flow, due to which metal parts are cut, at the exit from the nozzle is about 2–3 meters per second.

At the moment when the plasma jet comes into contact with the surface of the metal part, an electric current from the electrode begins to flow through it, and the original arc goes out. The new arc that burns between the electrode and the workpiece is called cutting.

A characteristic feature of plasma cutting is that the metal being processed melts only in the place where it is exposed to the plasma flow. That is why it is very important to ensure that the plasma exposure spot is strictly in the center of the working electrode.

If you neglect this requirement, you may encounter the fact that the air-plasma flow will be disrupted, which means the quality of the cut will deteriorate. In order to meet these important requirements, a special (tangential) principle of air supply to the nozzle is used.

It is also necessary to ensure that two plasma flows do not form at once instead of one. The occurrence of such a situation, which is caused by non-compliance with the modes and rules of the technological process, can provoke failure of the inverter.

Parameters of plasma cutting of various metals (click to enlarge)

An important parameter for plasma cutting is the air flow speed, which should not be too high. Good cutting quality and speed of execution are ensured by an air jet speed of 800 m/sec. In this case, the current supplied from the inverter apparatus should not exceed 250 A. When performing work in such modes, one should take into account the fact that in this case the air flow used to form the plasma flow will increase.

It’s not difficult to make a plasma cutter yourself if you study the necessary theoretical material, watch a training video and select all the necessary elements correctly. If you have such a device in your home workshop, assembled on the basis of a serial inverter, you can perform high-quality not only cutting, but also plasma welding with your own hands.

If you don’t have an inverter at your disposal, you can assemble a plasma cutter using a welding transformer, but then you’ll have to put up with its large dimensions. In addition, a plasma cutter made on the basis of a transformer will not have very good mobility, since it is difficult to move it from place to place.

Source: http://met-all.org/oborudovanie/prochee/plazmorez-svoimi-rukami-iz-invertora.html

Plasma cutting for beginners

Dear customers, in this article we want to tell you what plasma cutting of metals is, show its main advantages, tell you about the design of plasma devices and how to use them, and now about all this in order.

Sometimes our customers, when purchasing a plasma cutting machine, are surprised to learn that a compressor is required for its operation. A compressor is needed to blow out the metal you are cutting. It is impossible to cut with plasma without a compressor.

The compressor is connected to the device, and a plasmatron (plasma torch) is connected to the device, and so, when a pilot arc occurs between the cathode and the nozzle, the air blows this arc out, where the arc turns into the main arc in contact with the metal; Next, the process of melting the metal and blowing its liquid part out of the melt zone occurs.

When choosing a compressor, you should pay special attention to its quality and its parameters. Correct operation of a plasma cutting machine is only possible in combination with a good compressor. We recommend using compressors capable of delivering 5-6 atmospheres.

There is one more important detail that we would like to draw your attention to. The compressor must have an air filter; it can be built into the compressor initially, or it can be connected separately.

The air that will pass through the plasma cutting machine and exit the plasmatron must be clean and no foreign objects or substances must enter it. The ingress of vapors and oil particles, the smallest particles of metal shavings, dust and dirt is unacceptable.

This is especially important if you plan to use plasma in dusty industries, garages, workshops with concrete floors, etc. The cleaner the air, the better the cut!

If you comply with these conditions, the device will work correctly and without failures.

Plasma or gas cutter?

We will not say that gas cutting is worse than plasma cutting. Gas cutting has a number of advantages over plasma; for example, when cutting large quantities of scrap metal, you will not be able to cope with this task if you use plasma cutting. Plasma cutting is economically feasible for metal thicknesses up to 50 mm; for larger thicknesses, the advantage goes to oxygen cutting. But the quality and speed of cutting are always on the side of plasma cutting.

Gas cutting requires gas, plasma requires electricity. Let’s highlight two main advantages of plasma: first, you don’t need gas (acetylene) and you don’t come into contact with explosive gases, second, you can cut various types of metals (steel, stainless steel, copper, aluminum, etc.)

Thus, some people need a gas cutting machine, others need a plasma cutter, the choice is yours.

How to choose the right plasma cutting machine?

Everything is very simple here. The more powerful the plasma machine, the thicker the metal it can cut. If you plan to cut different thicknesses, it is better for you to choose a powerful device; if you are cutting thin metals, you do not need to buy a powerful device, just buy a forty-amp device.

Pay attention to such a thing as cut quality. The cut can be “dirty” or “clean”. A dirty cut is when you just need to cut a piece of metal and it doesn’t matter to you what kind of cut it will be, neat or not. A clean cut is metal cut as evenly as possible. As a rule, manufacturers indicate dirty cutting in the parameters.

To understand the clean cut, you need to subtract about 25% from the specified thickness. So, for example, if the manufacturer indicated 12 mm, then the clean cut will be 8-9 mm. Do not think that manufacturers are deceiving you; it is a worldwide practice to indicate a dirty cut in the parameters, not a clean one.

This parameter shows the maximum capability of the device, and you yourself choose how you want to cut metal, “dirty” or “clean”.

In addition, before purchasing, it is advisable to understand how often you will turn on the plasma cutting machine. Pay attention to the PV of the purchased device. If the device's duty cycle is 60%, then in a 10-minute cycle you can cut for 6 minutes, and the device will rest for 4 minutes; if the duty cycle is 100%, then you can not stop working, the device will work constantly.

Consumable parts

When purchasing a plasma cutting machine, we recommend that you ask the supplier about the consumables for the plasma torch. Almost all manufacturers include consumable parts with the device; you can start cutting immediately, but the consumables burn out, regardless of the manufacturer. And when the question of replacement arises, it turns out that where the device was purchased there are no “expenses”.

We often come across such cases when we help people choose consumables, and we must admit that this does not always work out. The expenses don't always add up. For example, consumables for devices of Chinese origin are not suitable for European or American products. In addition, there is no way to change the plasmatron (plasma torch) - different connectors.

Our online store sells plasma cutting machines made in China, all consumable parts for CUT torches are always in stock and, as practice shows, Chinese consumables are suitable for almost all devices made in China.

Speed at which to cut metal

This is a question we are often asked by customers. There is no definite answer to this; you will understand how quickly you will need to move the plasmatron through metal only during the learning process; it is very easy to get used to it. It all depends on the thickness of the metal and the amperage you set.

When you start cutting, you will immediately see whether you are driving the plasma torch very quickly (in which case the metal will not be cut completely) or very slowly (in which case you will simply waste air and electricity).

Before cutting the workpieces or pieces you need, we recommend practicing on unnecessary scraps to choose the optimal cutting mode and speed.

Another tip: when you turn on the machine, set the current to maximum, and while cutting, reduce it until you understand that this current is enough to cut your thickness of metal. Start with high currents, then go lower.

And also, do not try to set the maximum current in order to cut it off faster, since the higher the current, the faster the consumable fails; do not ignite too frequently, since it is at the moment of ignition that the refractory insert on the cathode intensively “weathers” and causes its premature failure, i.e. press the button and cut continuously. If your working conditions require you to make short cuts, for example, to cut mesh, get ready to frequently replace the consumables.

How it all works

Plasma cutting machines have an open circuit voltage of 250-300 V.

When you press the button, compressed air is supplied and at the same time this open circuit voltage is applied between the cathode and the nozzle in the internal chamber of the plasma torch, but in order to break through this gap and ignite the plasma, an ignition spark is needed - this ignition function is performed by an oscillator (ignition voltage is about 5-10 kV) .

As soon as the arc is ignited (and the arc at this moment is called pilot), the air blows the plasma out. The pilot arc current, as a rule, in powerful devices is limited internally by a powerful resistance to save consumption; it is not intended for cutting; The pilot arc burns for 2-3 seconds.

If during this time the arc does not touch the metal or the metal is for some reason not connected to the “+” of the installation (for example, a break in the return cable), then the arc goes out. If everything went well, then the pilot arc goes into the main arc, and the oscillator unit is turned off. Next, the metal is melted by an arc and the molten material is simultaneously blown out of the melt.

The main arc burns between a refractory hafnium insert pressed into the end of the cathode and the material of the product. The greatest destruction of this insert occurs precisely at the moment of ignition, so it is better to try to avoid turning it on too often in order to save consumption.

You can select a plasma cutting machine here.

For clarity, we conducted several tests. The Svarog CUT 100 machine cut metal 10 mm thick. with magnification up to 35 mm. The cutting current was set to 90 Amps.

The Svarog CUT 40 device cut a plate 4 mm thick. Cutting current 20 Amps.

Technical characteristics of AuroraPro devices →← About consumable parts for CUT burners in accessible language.

Source: https://svarkamall.ru/obzory/93-plazmennaja-rezka-dlja-nachinajuschih.html