In industry, welding using a plasma machine is used quite often when it is necessary to carry out procedures at high temperatures. Despite the complexity of the process and its special operating principle, do-it-yourself plasma welding is quite possible. The main temperature source here is plasma, which is obtained by transitioning one of the combustible gases to a new state of aggregation. This happens in a device called a plasmatron.
This type is excellent for working with all metals, since in addition to high temperature, plasma also provides additional protection. Homemade plasma welding can work with stainless steel, aluminum and even refractory metals. Despite the fact that this technology is most often used in modern high-tech fields, such as the aviation industry, the need for high-temperature welding in other fields periodically arises. Accordingly, do-it-yourself plasma welding is becoming increasingly in demand for less critical applications.
One of the features of this method is the high depth of metal penetration. The high temperature of the plasma, reaching several tens of thousands of degrees Celsius, allows metal to be melted up to 1 cm in one pass. Welding can be carried out in any spatial position, therefore, a universal joining method is presented here.
Plasma welding modes
This technology is most often used to work with refractory metals such as titanium, copper and others. To achieve high quality joints, one should take into account not only the properties of the metals themselves, but also the conditions of the plasma welding process. In order for everything to go as reliably as possible, you should navigate the following modes:
| l cv, A | U d, V | v St, m/h | Gas consumption Q g, l/min | |||
| For plasma formation | For guard | For blowing | ||||
| 139 | 22 | 30 | 2,1 | 1,5 …2,0 | 3,5.. .4,0 | |
| 6 | 240 | 23 | 14 | 5,5 | 9.4 | |
| 380 | 28 | 15 | 3,5 | 10,5 | 42 | |
| 13 | 450 | 28.. .30 | 103 | 8 | 6… 12 | |
Plasma apparatus diagram
To make your own plasma welding, drawings are one of the main points, since they contain all the main structural elements. Regardless of what parts you are going to make the equipment from, the diagram helps to determine the smallest components that should be included there. Here is the power circuit of the plasma torch:
Plasma torch circuit - power part
A plasma cutter is the main feature of such installations, since plasma is formed in it. This is also the main difficulty when creating plasma welding with your own hands from an inverter. Here is a control diagram for this device:
Plasma torch circuit - control system
Plasma apparatus assembly equipment
To create a working device you will need:
- , for example, for ;
- Argon cylinder;
- Reducer for cylinder;
- Nozzle with tungsten electrode;
- Fluoroplastic tube;
- Rod made of molybdenum or tantalum;
- Copper tubes;
- Electronic ballast;
- Wiring;
- Clamps;
- Sheet copper up to 2 mm thick;
- Terminals;
- Germovvod;
- Rubber hose;
- Rectifier power supply.
Build process
The peculiarities of plasma welding require precise procedures in order to ultimately obtain a reliable and safe device. The nozzle for this device is machined from copper, since otherwise it will have to be changed frequently. Instead of copper, you can use titanium, which will last much longer. The size of the hole in the nozzle is selected experimentally. As a rule, they start with a minimum value of 0.5 mm and gradually reach 2 mm.
The size of the conical gap between the anode on the nozzle and the tungsten cathode should be up to 3 mm. The nozzle is screwed into a full cooling jacket. It must be connected to the central electrode, for which a fluoroplastic insulator is used. For cooling, a liquid is used in the jacket, which must constantly circulate liquid or antifreeze. This device consists of two hollow copper pipes. The diameter of the inner one is about 2 cm. It is located at the front end of the outer tube, the diameter of which is 5 cm and the length is about 8 cm.
The space between the inner and outer pipes should be soldered using sheet copper. Small diameter copper tubes are soldered into the cooling jacket. It is through them that the liquid will subsequently circulate.”
A positive charge for this system will be supplied to a special terminal, which should also be soldered to the case. A thread is created on the inner pipe, into which a removable nozzle made from heat-resistant materials is then placed. The internal thread is also cut on the extended end of the outer pipe. A fluoroplastic ring is screwed onto it for insulation. The ring of the central electrode is located on it.
The argon supply pipe is pressed through the pipe wall between the insulator and the cooling jacket. A 12V pump is used to power the system. A positive charge is supplied to the system from the main power source. The ballast serves to limit the current in the system. To excite a pilot arc with a nozzle or tungsten electrode, you need to use an oscillator, or if you don’t have one, then everything can be done using the usual contact method.
Every year the pace of industrial development increases. This leads to the introduction of new technologies and methods for manufacturing certain products. At the same time, innovations must not only be more effective than obsolete methods, but also not inferior in terms of economic feasibility and operational safety. Let's talk about what plasma welding is. It appeared relatively recently, but is already very actively used in many
About plasma welding
This connection method is used for metal pipes, stainless steel and some other materials. The essence of the method is local melting when directing the plasma flow to the desired area. Plasma is an ionized gas stream that contains many charged particles that actively conduct electric current. When heated, gas ionization occurs, which is achieved by using a high-speed arc emerging directly from the plasmatron. Naturally, as the temperature of the gas increases, the degree of ionization increases. The temperature amplitude of the arc is not less than 5 and not higher than 30 thousand degrees Celsius. Of course, today plasma welding is used everywhere, but the equipment, in particular the plasma torch, is very expensive. In this way, you can connect parts without cutting edges, which is very convenient.
Principle of operation
Plasma welding is possible only if it is possible to obtain a plasma arc from a conventional arc. This is usually achieved by compression and using a system of forced supply of special gas into the arc. Argon with a small amount of helium or hydrogen is used as a plasma-forming gas. It is extremely important to create a protective shell around the electrode; argon is best suited for these purposes. By the way, the electrodes are made of tungsten activated with thorium or yttrium. It is worth noting that the walls of the plasma torch become very hot due to high pressure, so they need to be constantly cooled. From all of the above, we can conclude that plasma welding is notable for its high temperature in combination with a small arc diameter. The last parameter allows you to increase the pressure on the metal several times. In addition, the process is maintained at a low current of 0.2-3.0 Amperes.
DIY plasma welding
At first, this type was not used among home craftsmen, as it required high qualifications. Today the situation has not changed dramatically. However, there are ones that are suitable for use in domestic conditions. The technology in this case is quite simple. You will need to acquire special electrodes and filler wire.
Before starting work, the electrode is sharpened to a cone-shaped shape with an angle of no more than 30 degrees. It is extremely important to install the electrode correctly. The main thing is to ensure that the axis of the electrode coincides with the axis of the gas-forming nozzles. The welding joint is processed in exactly the same way as with argon welding. The edges are cleaned and degreased, only then can work begin. By the way, pay attention to the absence of gaps larger than 1.5 mm. Tack areas need to be further cleaned and care must be taken to ensure that the tack spots and weld are of similar quality.
We continue to carry out work
Do-it-yourself plasma welding is performed at a value that should not fall outside the recommended range. In addition, 5-20 seconds before the start of welding, shielding gas is supplied, which turns off approximately 10-15 seconds after the arc breaks. During operation, the plasma torch should be at a distance of no more than 1 cm from the product, and it is advisable not to break the arc until the end of the seam. When welding, do not allow the metal to overheat. When the critical point is reached, plasma welding is suspended. The metal is cooled with compressed air, and only after this work is resumed. Please note that the burner should move smoothly and evenly, as on an automatic device. In this case, you can count on a truly high-quality and reliable seam.
Plasma welding “Gorynych”: price and features
The multifunctional welding machine "Gorynych" is one of the most famous among domestic devices. We can say that this is a really high-quality product, thanks to which you can carry out welding work yourself. It is worth noting that the Gorynych model range differs in power. There are 8, 10 and 12 Amp models. The first option is perfect for household needs, the middle one has an excellent price/performance ratio, and the most powerful Gorynych is used only by professionals. So, an 8 Ampere model will cost 29 thousand, a 10 A model will cost 30 thousand, and a 12 A model will cost 33,000 rubles. In principle, Gorynych plasma welding, the price of which is lower than that of foreign analogues, is very popular in Russia, Ukraine, Belarus and other countries.
Plasma welding machine
If earlier it was very difficult to find a suitable model, today there are no problems with this. As a rule, a plasma welding machine can be found in any specialized store. You will be pleasantly surprised by the large selection of units offered. But they are all much more expensive than electric welding and inverters. The plasma device looks very advantageous compared to other options. Firstly, the speed of work performed is many times higher, and secondly, there is practically no waste left. To operate a plasma welder, you need electricity and compressed air, and if you have a special compressor, you only need a connection to the network. The burner nozzle and electrode must be replaced periodically. In addition, the plasmatron must be refilled regularly. For this purpose, special cylinders are used. Interestingly, welding is also considered the safest. However, it is advisable to carry out work outdoors or in a well-ventilated area.
About medium current welding
We already know a little about what plasma welding is. The price of equipment, as you can see, depends on its power. But it is worth paying attention to the fact that there are several types of welding. One of them is operation at medium current (50-150 Amperes). This type of welding can be compared with argon welding, but it is considered somewhat more efficient, since the arc power is higher and the heating area is limited. This option, compared to a traditional arc, allows you to increase the depth of penetration of the metal being processed and improve the transfer of heat deep into the layers. In principle, this is due not only to the energy characteristics, but also to the high pressure on the weld pools. Medium current welding is performed using filler wire. Today this is a very popular and effective solution. If you are going to work at home, this type of plasma welding is suitable for you. The price of the equipment will not differ, since it provides for the possibility of adjustment.
High current welding
In this case, work takes place under a current of over 150 Amperes. This is necessary to obtain greater impact on the metal. In fact, welding at 150 A is similar to welding at the same temperature with a non-consumable electrode. A distinctive feature of this solution is that during the work a through hole is formed in the bathroom, which guarantees complete penetration of the surface being treated. But here it is extremely important to follow the technology, since if you are careless you can easily get burns. In addition, other important parameters must be observed: cooling of the plasmatron and its storage conditions, periodic replacement of the burner nozzle, refueling and much more. In principle, instructions are written for a reason, and the requirements must be followed. Typically, a plasma welding and cutting machine operating at high current is necessary for joining alloy and low-carbon steels, copper, titanium and other materials.
A plasma cutting machine is a fairly popular piece of equipment that allows cutting any metals in many areas of production. Plasma cutters are used not only in enterprises. Recently, they have begun to appear in home workshops. But, since almost every workshop already has welding machines, it would be wiser not to buy a ready-made plasma cutter, but to make one from an inverter with your own hands.
In some cases, a plasma cutter is an indispensable tool for processing metal products, since the temperature of the plasma leaving its torch reaches 25-30 thousand degrees. Thanks to these characteristics, the scope of application of plasma cutters is quite extensive:
- production of various types of metal structures;
- laying of pipelines;
- fast cutting of any metals, including high-alloy heat-resistant steels containing titanium, nickel and molybdenum, the melting point of which is above 3000°C;
- shaped cutting of thin-sheet materials (conductive) due to high cutting accuracy.
In addition, plasma cutters (as an alternative to laser cutters) are used as part of automatic lines at large enterprises for cutting parts of various configurations from sheet materials.
It is necessary to distinguish between concepts such as plasma cutting and plasma welding. The latter is available only on expensive, professional equipment, the cost of which starts from 100 thousand rubles.
Inverter or transformer
There are various methods, as well as drawings and diagrams, according to which you can make a plasma cutter. For example, if it is made on the basis of a transformer welder, then the plasma cutter diagram provided below is suitable, which describes in detail what parts are needed to manufacture this module.
If you already have an inverter, then in order to convert it into a plasma cutter, you will need a little modification, namely adding an oscillator to the electrical circuit of the device. It is connected between the inverter and the plasma torch in two ways, as shown in the following figure.
The oscillator can be soldered independently according to the diagram provided below.
If you make a plasma cutter yourself, then choosing a transformer as a current source is not recommended for several reasons:
- the unit consumes a lot of electricity;
- The transformer is heavy and inconvenient to transport.
Despite this, the welding transformer also has positive qualities, for example, insensitivity to voltage changes. It can also cut thick metal.
But advantages of an inverter plasma cutting machine in front of the transformer unit there is:
- light weight;
- high efficiency (30% higher than that of a transformer);
- low electricity consumption;
- High-quality cutting thanks to a more stable arc.
Therefore, it is preferable to make a plasma cutter from a welding inverter than from a transformer.
Typical plasma cutter design
To assemble a device that will make air plasma cutting of metals possible, you will need to have the following components available.
Assembling the device
After all the necessary elements have been prepared, you can begin assembling the plasma cutter:
- connect a hose to the inverter through which air will be supplied from the compressor;
- connect the hose package and ground cable to the front side of the inverter;
- Connect the torch (plasma torch) to the hose package.
After assembling all the elements, you can begin equipment testing. To do this, connect the ground cable to the part or metal table on which it is placed. Turn on the compressor and wait until it pumps the required amount of air into the receiver. After the compressor automatically turns off, turn on the inverter. Bring the torch close to the metal and press the start button to create an electric arc between the torch electrode and the workpiece. Under the influence of oxygen, it will turn into a stream of plasma, and metal cutting will begin.
In order for a homemade plasma cutter from a welding inverter to work effectively and for a long time, you should listen to the advice of specialists related to the operation of the device.
- Recommended to have a certain number of gaskets which are used to connect hoses. Their presence should especially be checked when the unit has to be transported frequently. In some cases, the absence of the necessary gasket will make the device impossible to use.
- Because the cutter nozzle is exposed to high temperatures, it will wear out and fail over time. Therefore, you should worry about purchasing spare nozzles.
- When selecting components for a plasma cutter, you should consider how much power you want to get from the unit. First of all, this concerns the choice of a suitable inverter.
- When choosing an electrode for a burner, if you make it yourself, you need to give preference to a material such as hafnium. This material does not emit harmful substances during heating. But it is still strongly recommended to use ready-made cutters manufactured at the factory, in which all parameters for air flow swirl are observed. A homemade plasmatron does not guarantee high-quality cutting and quickly breaks down.
As for safety rules, work should be carried out in special clothing that protects against splashes of hot metal. You should also wear chameleon welding goggles to protect your eyes.
Modern inverter welding machines cover most of the needs for producing permanent joints of metal workpieces. But in some cases, a device of a slightly different type will be much more convenient, in which the main role is played not by an electric arc, but by a flow of ionized gas, that is, a plasma welding machine. Purchasing it for occasional use is not very cost-effective. You can make such a welding machine with your own hands.
Equipment and components
The easiest way to make a microplasma welding machine is on the basis of an existing inverter welding machine. To complete this upgrade, you will need the following components:
- any inverter welding machine for TIG welding with or without a built-in oscillator;
- nozzle with a tungsten electrode from a TIG welder;
- argon cylinder with reducer;
- a small piece of tantalum or molybdenum rod with a diameter and length of up to 20 mm;
- fluoroplastic tube;
- copper tubes;
- small pieces of copper sheet 1-2 mm thick;
- electronic ballast;
- rubber hoses;
- sealed lead-in;
- clamps;
- wiring;
- terminals;
- car windshield wiper reservoir with electric pump;
- rectifier power supply for the electric windshield wiper pump.
Work on fine-tuning and manufacturing of new parts and assemblies will require the use of the following equipment:
- lathe;
- electric soldering iron;
- soldering torch with cylinder;
- screwdrivers;
- pliers;
- ammeter;
- voltmeter.
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Theoretical basis
A plasma welding machine can be one of 2 main types: open and closed. The main arc of an open-type welding machine burns between the central cathode of the torch and the workpiece. Between the nozzle, which serves as the anode, and the central cathode, only a pilot arc burns to excite the main one at any time. A closed-type welding machine has only an arc between the central electrode and the nozzle.
It is quite difficult to make a durable one according to the 2nd principle. When the main welding current passes through the anode nozzle, this element experiences enormous thermal loads and requires very high-quality cooling and the use of appropriate materials. It is very difficult to ensure the heat resistance of the structure when making such a device yourself. When making a plasma device with your own hands, for durability it is better to choose an open circuit.
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Practical implementation
Often, when making a homemade plasma welding machine, the nozzle is machined from copper. If there is no alternative, this option is possible, but the nozzle becomes a consumable even when only a standby current passes through it. It will have to be changed frequently. If you can get a small piece of molybdenum or tantalum round timber, it is better to make a nozzle from them. Then you can limit yourself to periodic cleaning.
The size of the central hole in the nozzle is selected experimentally. You need to start with a diameter of 0.5 mm and gradually bore it to 2 mm until the plasma flow is satisfactory.
The conical gap between the central tungsten cathode and the anode nozzle should be 2.5-3 mm.
The nozzle is screwed into a hollow cooling jacket, which is connected to the central electrode holder through a fluoroplastic insulator. Coolant circulates in the cooling jacket. As such, in the warm season you can use distilled water; in winter, antifreeze is better.
The cooling jacket consists of 2 hollow copper tubes. The inner one with a diameter and length of about 20 mm is located at the front end of the outer tube with a diameter of about 50 mm and a length of about 80 mm. The space between the ends of the inner tube and the walls of the outer tube is sealed with thin sheet copper. Copper tubes with a diameter of 8 mm are soldered into the jacket using a gas torch. Coolant flows in and out through them. In addition, a terminal must be soldered to the cooling jacket to supply a positive charge.
A thread is made in the inner tube into which a removable nozzle made of heat-resistant materials is screwed. An internal thread is also cut at the extended end of the outer tube. An insulating ring made of fluoroplastic is screwed into it. The central electrode holder is screwed into the ring.
An argon supply tube of the same diameter as for cooling is soldered through the wall of the outer tube into the space between the cooling jacket and the fluoroplastic insulator.
Liquid from the windshield wiper reservoir circulates through the cooling jacket. Power is supplied to the pump of its electric motor through a separate 12 V rectifier. There is already an outlet for the supply on the tank; the liquid return can be cut through the wall or lid of the tank. To do this, a hole is drilled in the lid and a piece of tube is inserted through the pressure seal. Rubber hoses for liquid circulation and argon supply are connected to their tubes with clamps.
The positive charge is taken from the main power source. A suitable electronic ballast is selected to limit the current through the nozzle surface. The supplied electric current must have a constant value in the region of 5-7 A. The optimal current value is selected experimentally. This should be the minimum current that ensures stable combustion of the pilot arc.
The pilot arc between the nozzle and the tungsten cathode can be excited in one of two ways. Using an oscillator built into the welding machine or, in the absence of one, using a contact method. The second option requires a more complex design of the plasma torch. During contact excitation, the central electrode holder is made spring-loaded relative to the nozzle.
When the rubber button of the rod connected to the electrode holder is pressed, the sharp end of the central tungsten cathode contacts the conical surface of the rod. During a short circuit, the temperature rises sharply at the point of contact, which allows an arc to be initiated when the cathode is pulled away from the anode by a spring. The contact must be very brief, otherwise the surface of the nozzle will burn.
Excitation of current by a high-frequency oscillator is preferable for the durability of the structure. But purchasing it or even manufacturing it makes it unprofitable for plasma welding.
During operation, the positive terminal of the welding machine is connected to the part without ballast. When the nozzle is within a few millimeters of the workpiece, electrical current is switched from the nozzle to the workpiece. Its value increases to that set on the welding machine, and the formation of plasma from argon intensifies. By adjusting the argon supply and welding current, you can achieve the required intensity of plasma flow from the nozzle.
Unlike, the inverter is compact, light weight and high efficiency, which explains its popularity in home workshops, small garages and workshops.
It allows you to cover most needs for welding work, but for high-quality cutting you need a laser machine or plasma cutter.
Laser equipment is very expensive, and a plasma cutter is also not cheap. small thickness has excellent characteristics that are unattainable when using electric welding. At the same time, the power unit of the plasma cutter has largely the same characteristics.
There is a desire to save money and, with a little modification, use it for plasma cutting. It turned out that this is possible, and you can find many ways to convert welding machines, including inverter ones, into plasma cutters.
A plasma cutting machine is the same welding inverter with an oscillator and a plasma torch, a work cable with a clamp and an external or internal compressor. Often the compressor is used externally and is not included in the package.
If the owner of a welding inverter also has a compressor, then you can get a homemade plasma cutter by purchasing a plasma torch and making an oscillator. The result is a universal welding machine.
Operating principle of the burner
The operation of a plasma welding and cutting apparatus (plasma cutter) is based on the use of plasma, the fourth state of matter, as a cutting or welding tool.
To obtain it, high temperature and gas under high pressure are required. When an electric arc is created between the anode and cathode of the burner, a temperature of several thousand degrees is maintained in it.
Plasma formation
If you pass a gas stream through an arc under such conditions, it will ionize, expand in volume several hundred times and heat up to a temperature of 20-30 thousand °C, turning into plasma. High temperature almost instantly melts any metal.
Unlike a cumulative projectile, the process of plasma formation in a plasmatron is adjustable.
The anode and cathode in a plasma cutter are located at a distance of several millimeters from each other. The oscillator generates a pulsed current of high magnitude and frequency, passes it between the anode and the cathode, which leads to the occurrence of an electric arc.
After this, gas is passed through the arc, which is ionized. Since everything happens in a closed chamber with one exit hole, the resulting plasma rushes out at tremendous speed.
At the output of the plasma cutter torch, it reaches a temperature of 30,000 ° and melts any metal. Before starting work, a ground wire is connected to the workpiece using a powerful clamp.
When the plasma reaches the workpiece, an electric current begins to flow through the mass cable and the plasma reaches maximum power. The current reaches 200-250 A. The anode-cathode circuit is broken using a relay.
cutting
When the main arc of the plasma cutter disappears, this circuit turns on again, preventing the plasma from disappearing. Plasma plays the role of an electrode in electric arc welding; it conducts current and, due to its properties, creates an area of high temperature in the area of contact with the metal.
The contact area between the plasma jet and the metal is small, the temperature is high, heating occurs very quickly, so there is virtually no stress or deformation of the workpiece.
The cut is smooth, thin and does not require further processing. Under the pressure of compressed air, which is used as a plasma working fluid, the liquid metal is blown out and a high-quality cut is obtained.
When using inert gases with a plasma cutter, you can carry out high-quality welding without the harmful effects of hydrogen.
DIY plasma torch
When making a plasma cutter from a welding inverter with your own hands, the most difficult part of the work is the production of a high-quality cutting head (plasma torch).
Tools and materials
If you make a plasma cutter with your own hands, it is easier to use air as a working fluid. For production you will need:
Plasma cutter consumables in the form of nozzles and electrodes should be purchased at a welding equipment store. They burn out during the cutting and welding process, so it makes sense to purchase several pieces for each nozzle diameter.
The thinner the metal to be cut, the smaller the plasma cutter torch nozzle hole should be. The thicker the metal, the larger the nozzle opening. The most commonly used nozzle is the one with a diameter of 3 mm; it covers a wide range of thicknesses and types of metals.
Assembly
The plasma cutter torch nozzles are attached with a clamping nut. Directly behind it there is an electrode and an insulating sleeve, which does not allow an arc to occur in an unnecessary place in the device.
Then there is a flow swirler that directs it to the desired point. The entire structure is placed in a fluoroplastic and metal case. A pipe for connecting an air hose is welded to the outlet of the tube on the plasma cutter torch handle.
Electrodes and cable
The plasma torch requires a special electrode made of refractory material. They are usually made from thorium, beryllium, hafnium and zirconium. They are used due to the formation of refractory oxides on the surface of the electrode during heating, which increases the duration of its operation.
When used at home, it is preferable to use electrodes made of hafnium and zirconium. When cutting metal, they do not produce toxic substances, unlike thorium and beryllium.
The cable from the inverter and the hose from the compressor to the plasma cutter torch must be laid in one corrugated pipe or hose, which will ensure cooling of the cable in case of heating and ease of operation.
The cross-section of the copper wire must be selected at least 5-6 mm2. The clamp at the end of the wire must ensure reliable contact with the metal part, otherwise the arc from the pilot arc will not transfer to the main arc.
The compressor at the outlet must have a reducer to obtain normalized pressure at the plasma torch.
Options for direct and indirect action
The design of a plasma cutter torch is quite complex; it is difficult to do at home, even with various machines and tools, without a highly qualified worker. That's why the manufacture of plasma torch parts must be entrusted to specialists, or even better, buy it in a store. The direct action plasma torch torch was described above; it can only cut metals.
There are plasma cutters with indirect action heads. They are also capable of cutting non-metallic materials. In them, the role of the anode is played by the nozzle, and the electric arc is located inside the plasma cutter torch; only the plasma jet comes out under pressure.
Despite the simplicity of the design, the device requires very precise settings; it is practically not used in amateur production.
Refinement of the inverter
To use an inverter power source for a plasma cutter, it needs to be modified. You need to connect an oscillator with a control unit to it, which will serve as a starter that ignites the arc.
There are quite a lot of oscillator circuits, but the principle of operation is the same. When the oscillator is started, high-voltage pulses pass between the anode and cathode, which ionize the air between the contacts. This leads to a decrease in resistance and causes an electric arc.
Then the gas electric valve is turned on and under pressure air begins to pass between the anode and cathode through an electric arc. Turning into plasma and reaching the metal workpiece, the jet closes a circuit through it and the mass cable.
A main current of approximately 200 A begins to flow through the new electrical circuit. This triggers the current sensor, which turns off the oscillator. The functional diagram of the oscillator is shown in the figure.
Functional diagram of the oscillator
If you have no experience working with electrical circuits, you can use a factory-made oscillator of the VSD-02 type. Depending on the connection instructions, they are connected in series or in parallel to the plasmatron power circuit.
Before making a plasma cutter, you must first determine what metals and what thickness you want to work with. A compressor is sufficient to work with ferrous metal.
Cutting non-ferrous metals requires nitrogen; high-alloy steel requires argon. In this regard, you may need a trolley for transporting gas cylinders and reduction gears.
Like any equipment and tool, a welding machine with a plasma head requires certain skill from the user. The movement of the cutter should be uniform, the speed depends on the thickness of the metal and its type.
Slow movement results in a wide cut with jagged edges. Moving quickly will result in the metal not being cut through in all places. With proper skill, you can get a high-quality and even cut.