Making a plasma cutter welding machine tips. Assembling a homemade plasma cutter from an invetor or transformer

The operating principle of most plasmatrons with a power ranging from several kW to several megawatts is practically the same. An electric arc burns between a cathode made of a refractory material and an intensively cooled anode.

A working fluid (WM) is blown through this arc - a plasma-forming gas, which can be air, water vapor, or something else. Ionization of the RT occurs, and as a result, we obtain the fourth aggregate state of matter, called plasma.

In powerful devices, an electric magnet coil is placed along the nozzle; it serves to stabilize the plasma flow along the axis and reduce wear of the anode.

This article describes the second design, because The first attempt to obtain stable plasma was not particularly successful. Having studied the Alplaza device, we came to the conclusion that it is probably not worth repeating it one by one. If anyone is interested, everything is very well described in the instructions included with it.

Our first model did not have active anode cooling. The working fluid was water vapor from a specially constructed electric steam generator - a sealed boiler with two titanium plates immersed in water and connected to a 220V network.

The cathode of the plasmatron was a tungsten electrode with a diameter of 2 mm, which quickly burned out. The diameter of the anode nozzle hole was 1.2 mm, and it constantly became clogged.

It was not possible to obtain stable plasma, but there were still glimpses, and this stimulated the continuation of experiments.

In this plasma generator, a steam-water mixture and air were tested as the working fluid. The plasma output was more intense with water vapor, but for stable operation it must be overheated to a temperature of several hundred degrees so that it does not condense on the cooled plasmatron components.

Such a heater has not yet been made, so experiments so far continue only with air.

Photos of the insides of the plasmatron:

The anode is made of copper, the diameter of the nozzle hole is from 1.8 to 2 mm. The anode block is made of bronze and consists of two hermetically sealed parts, between which there is a cavity for pumping coolant - water or antifreeze.

The cathode is a slightly sharpened tungsten rod with a diameter of 4 mm, obtained from a welding electrode. It is additionally cooled by the flow of the working fluid supplied under pressure from 0.5 to 1.5 atm.

And here is a completely disassembled plasmatron:

Power is supplied to the anode through the cooling system tubes, and to the cathode through a wire attached to its holder.

Launch, i.e. The arc is ignited by twisting the cathode feed knob until it comes into contact with the anode. Then the cathode must be immediately moved to a distance of 2..4 mm from the anode (a couple of turns of the handle), and the arc continues to burn between them.

Power supply, connection of air supply hoses from the compressor and cooling system - in the following diagram:

As a ballast resistor, you can use any suitable electric heating device with a power of 3 to 5 kW, for example, select several boilers connected in parallel.

The rectifier choke must be designed for a current of up to 20 A; our example contains about a hundred turns of thick copper wire.

Any diodes are suitable, designed for a current of 50 A and above, and a voltage of 500 V.

Be careful! This device uses transformerless mains power.

The air compressor used to supply the working fluid is a car one, and a car glass washer is used to pump the coolant through a closed circuit. Power is supplied to them from a separate 12-volt transformer with a rectifier.

A little about plans for the future

As practice has shown, this design also turned out to be experimental. Finally got stable operation within 5 - 10 minutes. But there is still a long way to go to complete perfection.

Replaceable anodes gradually burn out, and it is difficult to make them from copper, and even with threads; it would be better without threads. The cooling system does not have direct contact of the liquid with the replaceable anode, and because of this, heat transfer leaves much to be desired. A more successful option would be with direct cooling.

The parts were machined from semi-finished materials at hand; the design as a whole was too complex to be repeated.

It is also necessary to find a powerful isolation transformer; without it, using the plasmatron is dangerous.

And finally, some more pictures of the plasmatron when cutting wire and steel plates. Sparks fly almost a meter :)

Undoubtedly, many of us have seen a video on YouTube where Vitaly Bogachev assembled a plasma cutter from a conventional arc welding machine
I'll try to explain in simple words without any fanaticism. Vitaly removed the secondary winding on the welding transformer and instead wound a new secondary winding with a cable of smaller cross-section to increase the output voltage to 200V. Next, I installed a diode bridge on the radiators and a choke wound on iron, similar to a larger welding transformer. I connected this thing to the cutter.
For purging I used regular air pumped by a compressor

Here is the first video in which Vitaly described the design of the device

In the second video, Vitaly showed how his homemade plasma cutter works. It can be seen that the cutter cuts metal up to 8mm, but Vitaly does not show the machine itself during cutting, even just going into this room and showing where the sleeve from the cutter goes, this is not there

Honestly, this idea really attracted me and I wanted to assemble a similar device, but here’s what alarmed me. Why do factory plasma cutting machines cost a lot of money if there is nothing so complicated in them, maybe there is a catch in the video and in fact the video is for PR

Firstly, you need a welding machine for arc welding AC 200A, or rather, you need a pair of such machines. The first transformer will be the power transformer, the second transformer will act as a choke. The welding transformer has three windings, two primary windings 0-220-400V, as well as a secondary winding 40V. This is what I plan to do with these transformers, cut both transformers, remove the secondary winding from the first and in its place put the primary of the second transformer, so I should get 200V on the secondary winding. Now about the throttle. I still have the iron from the second transformer, as well as two secondary windings that can be put on the second core and connected in series. You should get an excellent inductor with an as yet unknown inductance.
I looked at these welding transformers in the Yandex market and found the cheapest option at 2,376 ₽ per one. This means that for two, including delivery, it will cost approximately 6,500 RUR.
These are the welding machines

I go further, you need 4 diodes with a voltage of 600V or more, but 1000V is better. It is better to choose a larger current for diodes, say 150A will be just right. I'll turn to AliExpress for this matter. I found a suitable 150A 1600V diode bridge for reverse breakdown; such a good margin for reverse voltage will not be superfluous.


The price for such a diode bridge is 770.33 rubles, here is the link for purchase. You also need a radiator to cool the diode bridge, there are no better ideas than a radiator from a PC processor, such a radiator can be bought at a flea market for 100-200R. And that’s 1000R for the rectifier

To operate a plasma cutter you need a compressor, well, that’s a done deal, it was assembled a long time ago. A compressor is good, but the air must be clean, free of oil and moisture. This means that you need to install a desiccant in front of the cutter, which again is better to order from China. I liked the AF2000-02 G1/4 filter for 442.20 rubles.


The dehumidifier can withstand a pressure of 1.5 MPa, which is quite satisfactory. I also need a valve for control, I will use a valve like this, the price for it is 480 RUR. Here is the link

Also, to connect to each other, you need fittings with a diameter of 1/4 inches


As an option, you can order 5 pieces for 276 rubles. link here

The next component of a plasma cutter, and perhaps the main one, is the torch itself. Such a burner costs a lot here, but in China they also ask 2400 RUR for it.


From what the Chinese offer, this is the cheapest option. You can order one using this link. Also, to connect this sleeve you need a fitting, the same as I showed in the article about. I couldn’t find anything useful on the Internet, so I’ll have to order it from a turner. This is another 600-800 rubles

A few more components are needed for a complete set.
Several switches for controlling the power transformer and gas valve.

Such relays can be

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 remarkable 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 some that are suitable for use in living 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 greater 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 lineup“Gorynychey” 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 high pressure for weld pools. Medium current welding is performed using filler wire. Today it is 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. Distinctive feature 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.

Plasma cutting is actively used in many industrial fields. However, a plasma cutter is quite capable of being useful to a private master. The device allows you to cut any conductive and non-conductive materials with high speed and quality. The technology of work makes it possible to process any parts or create shaped cuts, which is carried out by a high-temperature plasma arc. The flow is created by basic components - electric current and air. But the benefits of using the device are somewhat overshadowed by the price of factory models. To provide yourself with the opportunity to work, you can create a plasma cutter with your own hands. Below we present detailed instructions with the procedure and list of equipment that is needed.

What to choose: transformer or inverter?

Due to the presence of features and parameters of plasma cutting devices, it is possible to divide them into types. Inverters and transformers have gained the most popularity. The cost of the device of each model will be determined by the declared power and operating cycles.

Inverters are lightweight, compact in size and consume minimal electricity. Disadvantages of the equipment include increased sensitivity to voltage changes. Not every inverter is able to function within the specific conditions of our electrical network. If the device’s protection system fails, you must contact a service center. Also, inverter plasma cutters have a rated power limitation of no more than 70 amperes and a short period of switching on the equipment at high current.

A transformer, traditionally, is considered more reliable than an inverter. Even with a noticeable drop in voltage, they lose only part of the power, but do not break. This property determines the higher cost. Plasma cutters based on a transformer can operate and be switched on for a longer period of time. Similar equipment is used in automatic CNC lines. The negative aspect of a transformer plasma cutter will be its significant weight, high energy consumption and size.

The maximum metal thickness that a plasma cutter can cut is from 50 to 55 millimeters. The average power of the equipment is 150 - 180 A.

Average cost of factory devices

The range of plasma cutters for manual cutting of materials is now truly huge. Price categories are also different. The price of devices is determined by the following factors:

• Device type;
• Manufacturer and country of production;
• Maximum possible depth cutting;
• Model.

Having decided to explore the possibility of purchasing a plasma cutter, you need to be interested in the cost of additional elements and components for the equipment, without which it will be difficult to fully operate. Average prices for devices, depending on the thickness of the metal being cut, are:

• Up to 6 mm – 15,000 – 20,000 rubles;
• Up to 10 mm – 20,000 – 25,000;
• Up to 12 mm – 32,000 – 230,000;
• Up to 17 mm – 45,000 – 270,000;
• Up to 25 mm – 81,000 – 220,000;
• Up to 30 mm – 150,000 – 300,000.

Popular devices are “Gorynych”, “Resanta” IPR-25, IPR-40, IPR-40 K.

As you can see the price range is wide. In this regard, the relevance of a homemade plasma cutter is increasing. Having studied the instructions, it is quite possible to create a device that is in no way inferior in technical specifications. You can select an inverter or transformer at a price significantly lower than the prices presented.

Operating principle

After pressing the ignition button, the source of electricity starts, supplying high-frequency current to the working tool. An arc (pilot) occurs between the tip located in the cutter (plasma torch) and the electrode. Temperature range from 6 to 8 thousand degrees. It is worth noting that the working arc is not created instantly; there is a certain delay.

Then compressed air enters the cavity of the plasmatron. This is what a compressor is designed for. Passing through the chamber with a pilot arc on the electrode, it is heated and increases in volume. The process is accompanied by ionization of the air, which transforms it into a conductive state.

Through a narrow plasma torch nozzle, the resulting plasma flow is supplied to the workpiece. The flow speed is 2 – 3 m/s. Air in an ionized state can heat up to 30,000°C. In this state, the electrical conductivity of air is close to the conductivity of metal elements.

After the plasma contacts the surface being cut, the pilot arc is switched off and the working arc begins to operate. Next, melting is carried out at the cutting points, from which the molten metal is blown with supplied air.

Differences between direct and indirect devices

Available Various types devices that differ in operating principles. In direct acting equipment, the operation of an electric arc is assumed. It takes on a cylindrical shape and is directly connected to the gas stream. This equipment design makes it possible to provide a high arc temperature (up to 20,000°C) and a highly efficient cooling system for other components of the plasma cutter.

In indirect-acting devices, operation is assumed to be less efficient. This determines their lower distribution in production. The design feature of the equipment is that the active points of the circuit are placed on special tungsten electrodes or a pipe. They are used more often for heating and spraying, but are practically not used for cutting. Most often used in car repairs.

A common feature is the presence in the design air filter(extends the service life of the electrode, ensures quick start-up of equipment) and cooler (creates conditions for long-term operation of the device without interruption). An excellent indicator is the ability of the device to operate continuously for 1 hour with a 20-minute break.

Design

With the proper desire and skill, anyone can create a homemade plasma cutter. But in order for it to function fully and effectively, certain rules must be followed. It is advisable to try on an inverter, because it is he who is able to provide a stable current supply and stable work arcs. As a result, there are no interruptions and electricity consumption will be significantly reduced. But it is worth considering that an inverter-based plasma cutter can cope with a thinner metal thickness than a transformer.

Required components

Before starting assembly work, it is necessary to prepare a number of components, materials and equipment:

1. Inverter or transformer with suitable power. To eliminate error, it is necessary to determine the planned cutting thickness. Based on this information, select the right device. However, taking into account manual cutting, it is worth choosing an inverter, because... it weighs less and consumes less electricity.
2. Plasma torch or plasma cutter. There are also some peculiarities of choice. It is better to choose direct action for working with conductive materials, and indirect action for non-conductive materials.
3. Compressed air compressor. It is necessary to pay attention to the rated power, because it must cope with the load imposed and match the other components.
   Cable hose. Required for connecting all components of the plasma cutter and supplying air to the plasma torch.

Selection of power supply

The operation of the plasma cutter is ensured by the power supply. It generates the specified parameters of electric current and voltage and supplies them to the cutting unit. The main supply unit can be:

• Inverter;
• Transformer.

It is necessary to approach the choice of power supply taking into account the features of the devices described above.

Plasma torch

A plasma torch is a plasma generator. This is a working tool in which a plasma jet is formed that directly cuts materials.

The main features of the device are:

• Creation of ultra-high temperature;
• Simple adjustment of current power, start and stop of operating modes;
• Compact dimensions;
• Reliability of operation.

Structurally, the plasma torch consists of:

• Electrode/cathode containing zirconium or hafnium. These metals are different high level thermionic emission;
• The nozzle is basically isolated from the electrode;
• A mechanism that swirls plasma-forming gas.

The nozzle and electrode are consumables of the plasma torch. If a plasma cutter processes a workpiece up to 10 millimeters in size, then one set of electrodes is consumed within 8 hours of operation. Wear occurs evenly, which allows you to change them at the same time.

If the electrode is not replaced in a timely manner, the cutting quality may be impaired - the geometry of the cut changes or waves appear on the surface. The hafnium insert in the cathode gradually burns out. If it has a production of more than 2 millimeters, then the electrode can burn and overheat the plasmatron. This means that electrodes replaced at the wrong time will lead to rapid failure of the remaining elements of the working tool.

All plasmatrons can be divided into 3 volume groups:

• Electric arc - has at least one anode and cathode, which are connected to a direct current power source;
• High-frequency - there are no electrodes and cathodes. Communication with the power supply is based on inductive/capacitive principles;
• Combined - operates when exposed to high-frequency current and arc discharges.

Based on the arc stabilization method, all plasmatrons can also be divided into gas, water and magnetic types. Such a system is extremely important for the operation of the instrument, because it forms a compression of the flow and fixes it on the central axis of the nozzle.

Currently, various modifications of plasma torches are available for sale. You may need to study the offers and buy a ready-made one. However, it is quite possible to make a homemade one at home. This requires:

• Lever. It is necessary to provide holes for wires.
• Button.
• An appropriate electrode designed for the current.
• Insulator.
• Flow swirler.
• Nozzle. Preferably a set with different diameters.
• Tip. Splash protection must be provided.
• Distance spring. Allows you to maintain a gap between the surface and the nozzle.
• Nozzle for removing carbon deposits and chamfering.

Work can be carried out with one plasma torch due to replaceable heads with different diameters that direct the plasma flow to the part. It is necessary to pay attention that they, like the electrodes, will melt during operation.

The nozzle is secured with a clamping nut. Directly behind it there is an electrode and an insulator that prevents the ignition of the arc in the wrong place. Next, a flow swirler is placed to enhance the arc effect. All elements are housed in a fluoroplastic casing. You can do some things yourself, but others will have to be purchased at the store.

The factory plasma torch will allow you to work without overheating for more than long time due to the air cooling system. However, for short-term cutting this is not an important parameter.

Oscillator

An oscillator is a generator that produces high-frequency current. A similar element is included in the plasma cutter circuit between the power source and the plasma torch. Capable of acting according to one of the following schemes:

1. Creation of a short-term impulse that promotes the formation of an arc without touching the surface of the product. Externally, it looks like a small lightning bolt supplied from the end of the electrode.
2. Constant voltage support with high voltage value superimposed on welding current. Ensures the preservation of stable arc maintenance.

The equipment allows you to quickly create an arc and start cutting metal.

For the most part they have a similar structure and consist of:

• Voltage rectifier;
• Charge storage unit (capacitors);
• Power unit;
• Pulse creation module. Includes an oscillatory circuit and a spark gap;
• Control block;
• Step-up transformer;
• Voltage monitoring device.

The main task is to modernize the incoming voltage. The frequency and voltage level increase, reducing the period of action to less than 1 second. The work sequence is as follows:

1. The button on the cutter is pressed;
2. In the rectifier, the current is leveled out and becomes unidirectional;
3. Charge accumulates in capacitors;
4. Current is supplied to the oscillatory circuit of the transformer windings, increasing the voltage level;
5. The pulse is controlled by a control circuit;
6. The pulse creates a discharge on the electrode, igniting an arc;
7. The impulse ends;
8. After stopping cutting, the oscillator purges the plasma torch for another 4 seconds. Due to this, cooling of the electrode and the treated surface is achieved.

Depending on the type of oscillator, it can be used in different ways. However general characteristic is to increase the voltage to 3000 - 5000 volts and frequency from 150 to 500 kHz. The main differences are in the intervals of action of the high-frequency current.

For use in a plasma cutter, it is advisable to use an oscillator for non-contact ignition of the arc. Similar elements are used to work in argon welders. The tungsten electrodes in them will quickly become dull if they come into contact with the product. Including an oscillator in the apparatus circuit will allow you to create an arc without making contact with the plane of the part.

Using an oscillator can significantly reduce the need for expensive consumables and improve the cutting process. Properly selected equipment in accordance with the planned work allows you to improve its quality and speed.

Electrodes

Electrodes play an important role in the process of creating, maintaining an arc and direct cutting. The composition contains metals that allow the electrode not to overheat and not prematurely collapse when working with an arc at high temperatures.

When purchasing electrodes for a plasma cutter, it is necessary to clarify their composition. Beryllium and thorium contents create harmful fumes. They are suitable for work in appropriate conditions, with adequate protection for the worker, i.e. additional ventilation is required. Because of this, for application in everyday life it is better to buy hafnium electrodes.

Compressor and cable - hoses

The design of most homemade plasma cutters includes compressors and hose lines to direct air to the plasma torch. This design element allows you to heat the electric arc up to 8000°C. An additional function is to purge the working channels, clearing them of contaminants and removing condensate. In addition, compressed air helps cool the components of the device during long-term operation.

To operate the plasma cutter, it is possible to use a conventional compressed air compressor. Air exchange is carried out by thin hoses with suitable connectors. An electric valve is located at the inlet, which regulates the air supply process.

An electrical cable is placed in the channel from the apparatus to the burner. Therefore, it is necessary to place a hose with a large diameter here, which can accommodate the cable. The passing air also has a ventilation function, as it is able to cool the wire.

The mass must be made of cable with a cross-section of 5 mm2. There must be a clamp. If there is poor ground contact, switching the working arc to the standby arc will be problematic.

Scheme

Now you can find many schemes using which you can assemble a high-quality device. Details from symbols The video will help you figure it out. A suitable schematic drawing of the equipment can be selected from those presented below.

Assembly

Before starting the assembly process, it is advisable to clarify the compatibility of the selected components. If you have never assembled a plasma cutter with your own hands before, you should consult with experienced craftsmen.

The assembly procedure assumes the following sequence:

1. Prepare all assembled components;
2. Electrical circuit assembly. In accordance with the diagram, an inverter/transformer and an electrical cable are connected;
3. Connecting the compressor and air supply to the apparatus and plasma torch using flexible hoses;
4. For your own safety net, you can use the source uninterruptible power supply(UPS), taking into account the battery capacity.

Detailed equipment assembly technology is presented in the video.

Checking the plasma cutter

After all nodes are connected into a single structure, it is necessary to test for functionality.

Please note that testing and working with the plasma cutter must be carried out in protective clothing using personal protective equipment.

It is necessary to turn on all the units and press the button on the plasma torch, supplying electricity to the electrode. At this moment, an arc with a high temperature should form in the plasmatron, passing between the electrode and the nozzle.

If the assembled plasma cutting equipment is capable of cutting metal up to 2 cm thick, then everything is done correctly. It should be noted that a homemade device made from an inverter will not be able to cut parts with a thickness of more than 20 millimeters, since there is not enough power. To cut thick products, you will need to use a transformer as a power source.

Advantages of a homemade device

The benefits provided by an air plasma cutting machine are difficult to overestimate. It is capable of cutting sheet metal accurately. After work, there is no need to further process the ends. The main advantage is the reduction in work time.

These are already compelling reasons for assembling the equipment yourself. The circuit is not complicated, so anyone can cheaply remake an inverter or semi-automatic device.

In conclusion, let us draw your attention to the fact that it is necessary for an experienced specialist to work with a plasma cutter. It's best if it's a welder. If you have little experience, we recommend that you first study the technology of working with photos and videos, and then begin to complete the assigned tasks.

• 1 Design features
• 2 Design of a plasma cutter, tips for making the device
• 3 How does a plasma cutter work?
• 4 Ventilation during plasma cutting
• 5 Homemade plasma cutter schemes

Making a plasma cutter with your own hands from an inverter is not as difficult as it seems at first. Before you start making the device yourself, you need to prepare everything you need:

• plasma cutter (plasma torch);
• an inverter device or a transformer that acts as a source of electric current;
• a compressor, with the help of which an air jet will be formed, forming and cooling the plasma flow;
• cables, hoses designed to connect all parts of the device.

When choosing a power source, you need to take into account the current generated by the device. An inverter inverter is often used, which makes the cutting process stable and saves electrical energy. An inverter, unlike a transformer, weighs little and has small size, so it is convenient to use. The main disadvantage of an inverter-based plasma cutter is that it is difficult for them to cut very thick workpieces.

To make a plasma cutter with your own hands, you can use the diagrams below. Below you will also find a video that explains the process of assembling the equipment. It is necessary to strictly follow the diagram, select the components so that the parts of the device fit together.

Design features

The first thing you need to find to create a plasma cutter is a power source. From it, an electric current with the required parameters will flow into the plasma cutter for metal processing. Usually a plasma cutter is made from a welding inverter. The use of a transformer can result in high electrical energy consumption. It must be remembered that any transformer welding device is large and weighs a lot.

An important component of the device is the plasma cutter. The quality of the cut and the efficiency of its implementation depend on it.

A compressor is used to create a stream of air that turns into a plasma jet. Electric current from the inverter/transformer and air flow from the compressor are supplied to the cutter through a cable and hose complex.

The plasma torch contains the following parts:

• nozzle hole;
• a channel for passing air flow;
• electrode;
• cooling insulator.

How to make a plasma cutter from an inverter? To make a plasma cutting device with your own hands, you need to choose the optimal electrode. Beryllium, thorium, zirconium, and hafnium electrodes are usually used. When heated, refractory oxide films are formed on the surface of these materials, preventing destructive processes.

Certain materials, when heated, release toxic substances. This must be taken into account when selecting an electrode. Beryllium releases radioactive oxides. Thorium vapors combine with oxygen to produce highly toxic elements. It is safest to use a hafnium electrode.

Do-it-yourself plasma cutter for metal creates a flow through a nozzle hole. This part of the device determines the efficiency of the work flow.

The optimal nozzle diameter is 15 millimeters. The nozzle is responsible for how accurately and efficiently the metal will be cut. Remember that a long nozzle is prone to wear out quickly.

A do-it-yourself plasma cutter for metal from an inverter must have a compressor. It creates and delivers an oxygen stream to the hole. The use of pressurized air as a working and cooling medium, together with an inverter device that supplies an electric current of 200 A, makes it possible to effectively cut steel parts with a thickness of up to 50 millimeters.

To prepare the plasma cutter for the work process, you need to connect the plasma torch, inverter device and compressor. Cables and hoses are used for this.

The cable through which electric current will flow serves to connect the inverter device and the electrode element.

The compressed air supply hose serves to connect the compressor output and the plasma torch.

How does a plasma cutter work?

How to make a plasma cutter for metal with your own hands? To understand this, you need to understand how this device functions. When the inverter device is turned on, electricity flows to the electrode. Because of this, an arc is ignited. The temperature of the electric arc that lights up between the working electrode and the metal end of the nozzle hole is approximately 6000-8000 degrees. After the arc is ignited, pressurized air enters the nozzle chamber. It passes through an electrical discharge. An electric arc provides heating and ionization of the air flow passing through it. Due to this, the volume of air is increased by 100 or more times. The air becomes able to pass electric current.

Using a nozzle, a plasma jet is formed from an air flow. Its temperature increases rapidly and can reach 25,000-35,000 degrees. The speed of the plasma jet, through which metal workpieces are cut, at the exit from the nozzle hole is approximately 2-3 meters per second. When the plasma jet touches the surface of a steel workpiece, electric current from the electrode element begins to flow through it, and the burning arc goes out. A new arc that lights up between the electrode element and the workpiece being cut is called cutting.

Distinctive feature Plasma cutting means that the material being cut melts only in the area in which the plasma jet acts on it. In view of this, it is necessary to ensure that the plasma exposure area is located in the central part of the electrode. If you ignore this requirement, you may encounter a disruption in the plasma-air flow. Consequently, the cutting efficiency will decrease. To ensure compliance, air is supplied tangentially to the nozzle.

Do not allow the formation of 2 plasma streams instead of one. If you do not follow the regimes and rules of implementation technological process, you can damage the inverter device.

A very significant characteristic of plasma cutting is the speed of the air stream. It shouldn't be very high. The best ratio of cutting quality and speed of execution is ensured at an air flow speed of 800 meters per second. The current coming from the inverter should not exceed 250 amperes. When cutting metal in this mode, it is necessary to take into account that the air flow used to form the plasma flow will be quite large.

It is not difficult to make a plasma cutting device with your own hands. You need to familiarize yourself with the theory, watch videos and choose the correct components of the device. The advantage of an inverter plasma cutter is that it can be used not only for cutting, but also for welding.

If you don't have an inverter, you can make a plasma cutter from a welding machine, i.e. transformer. However, in this case the device will have rather large dimensions. Also, the disadvantage of a plasma cutter for metal, which is made from a transformer, is that it is not very mobile. Due to this, it is difficult to move it from one place to another. This is not too critical if you rarely work with the device. However, if you often need to cut metal workpieces, be sure to start creating a plasma cutter from an inverter with your own hands.

Ventilation for plasma cutting

Ventilation is necessary for plasma cutting. When metal is cut with a device, smoke and dust particles are generated. They must be removed from the room in which the work is being carried out. For this purpose, ventilation systems are used, making it possible to solve this problem.

If plasma cutting is performed manually, inclined lifts are used. They provide suction of dust particles. It is worth remembering that the lower part of such a device should not be higher than thirty-five centimeters above the cutting area.

If large metal sheets are cut, special suction devices are used. Tables with a box are also often used for ventilation. The box serves as a kind of receiver for various particles formed during the working process. The main requirement for such a table is to cover its surface by eighty percent with the sheets being processed. This makes it possible to provide the desired air flow speed, suck in dust particles and smoky elements.

Ventilation for plasma cutting is considered effective if the air flow speed is 1.3 m/s (carbon steel, titanium alloys) or 1.8 m/s (aluminum alloys, high-alloy steel).

If you decide to make your own plasma cutter, carefully study the above recommendations. This way you can make a device that will function correctly and have a long service life. If you have an inverter machine, be sure to use it as a source of electricity, and not a welding transformer. Small dimensions devices are a significant advantage.

Homemade plasma cutter diagrams