How Does a Plasma Cutter Work?
Not all metals can be cut with an oxygen-gas flame. If you need to work with stainless steel, copper, or aluminum, you will need a plasma cutter.
Even when cutting ferrous metals, this device leaves fewer slag drops, and the cut itself is much thinner, which reduces subsequent processing and saves materials.
A detailed description of the equipment device and a rating of the best models will help you figure out how to choose a plasma cutter for different applications.
- Device and principle of operation of the plasma cutter
- Scope of application, pros, and cons of plasma cutting
- Types of plasma cutters
- Plasma cutters by cutting type
- Custom-made according to the type of gas used
- Custom-made according to the type of arc ignition
- Custom-made according to the type of cooling
- How to choose a plasma cutter
- The thickness of the cut metal
- Duration of activation
- The required compressor power
- Hose pack length
The best plasma cutters
- Aurora PRO AIRHOLD 42 Mosfet
- BRIMA CUT-40
- Resanta IPR 40
- BlueWeld Prestige Plasma 54 Kompressor
- Svarog REAL CUT 45 L207
The selection of products is based on the reviews, opinions, and ratings of users posted on various resources on the Internet.
All information is taken from open sources. We do not cooperate with manufacturers and brands and do not encourage the purchase of certain products.
The article is informational in nature.
Device and principle of operation of the plasma cutter
Plasma cutting equipment consists of:
- power supply;
- the ground wire;
- compressor or compressed air cylinder.
The power source is an inverter that produces a constant current, which has previously been converted several times with an increase in frequency.
The connection requires 220 or 380 V, depending on the characteristics of the device.
At the output, the device outputs a voltage of up to 400 V and a current of 25 to 125 A.
The burner in such equipment is called a plasma torch. It has a nozzle and a button to start the power supply.
The plasma torch can be manual or automatic type on a bracket with rails.
Components of the plasma cutter
The device of the plasma torch.
The principle of operation of the plasma cutter is to excite an electric arc into which compressed air is supplied.
From heating, it passes into plasma, which is used for cutting all types of metals and even ceramics.
The plasma temperature is about 20,000 degrees, which exceeds the oxygen cutting index by 6 times.
The plasma also has a high excision rate of 1500 m / s, which is not present in the gas-oxygen flame, which cuts due to a pressure of 10 atm from the cylinder.
These arc characteristics ensure a clean-cut, a narrow edge, and a minimum of slag on the back of the part.
For cutting with a plasma torch, the following processes are carried out in the equipment:
The current source supplies voltage to the cathode and anode located in the nozzle of the plasma torch.
An electric arc appears between them. At the same time, compressed air flows from the compressor, passed through the filter dryer.
The air passing through the arc is ionized and turns into plasma. This arc is called the duty arc and is lit only on the plasma torch.
Then the welder brings the torch to the workpiece. Thanks to the mass cable, which carries a positive charge and is connected to the product, the arc closes on the material.
The duty arc becomes the cutting arc. The welder controls the burner and cuts along the intended contour.
The plasma length and width can be adjusted by the current strength and the diameters of the installed nozzles.
When the cutting is completed, the welder removes the torch from the product and the duty arc is lit again.
Releasing the button, it is extinguished and for some time more air is supplied to cool the nozzle.
The principle of operation of the plasma cutter
Scheme of operation of the plasma cutter.
Scope of application, pros, and cons of plasma cutting
The equipment for plasma cutting of metals is used in factories and in private workshops.
It is used to cut sheet iron with a thickness of 1 to 100 mm (depending on the power of the device).
Plasma can cut complex patterns, burn holes, cut the edge.
Subsequent workpieces are used for welding to other structures or are subjected to turning, stamping.
Unlike oxygen flame, plasma cuts all types of metals and ceramics, so its functionality and application area is wider.
To determine whether you need a plasma cutter, consider the advantages and disadvantages of such equipment.
The main advantages of this method of cutting include:
High cutting speed
Thanks to the temperature of 20,000 degrees, the plasma cutter can cut workpieces much faster than other methods.
For example, a sheet with a cross-section of 25 mm will be cut at a speed of 1000 mm/min.
If you want to start cutting not from the edge of the sheet, but in the center, then the plasma will burn through a thickness of 15 mm in 2 seconds, and the gas-flame cutter will need about 30 seconds.
Minimal heating of adjacent areas
The plasma acts pointwise on the metal without heating the surface around it.
This reduces the number of deformations and allows you to hold on to large workpieces with gloved hands, turning them as necessary.
High quality of cutting
After the plasma, there are almost no leaking slag droplets on the back of the workpiece.
The edges contain a minimum of relief, so they do not need to be processed — you can immediately perform subsequent welding of structures.
If you need to cut thin sheets of 1-2 mm, then you can group them on top of each other and do everything at once — the blanks will not stick together at the edges.
Example of metal cut by a plasma cutter
An example of metal cut by a plasma cutter.
This equipment does not use flammable gases. The use of compressed air or inert gases makes the process safer — there will definitely be no explosion, as in the case of a reverse flame strike in an oxygen torch.
Ease of use
Unlike flame-cutting, there is no need to adjust the supply of fuel gas and oxygen separately, and then adjust the jet of cutting oxygen.
Everything is turned on with a single button and is available for quick development even for a beginner.
The possibility of automation
The plasma cutter is easy to complete with a bracket (portal or cantilever type), so that it automatically moves over the product.
The control is carried out with a CNC.
In it, the operator sets the configuration and speed of the cut, at the same time one person can monitor the processes on five installations.
Minimum preparation before the process
Plasma is able to cut any metal without first cleaning it from dirt or rust.
When working, there is no metal splashing and no air popping.
But this cutting method also has disadvantages that you need to know in order to choose a plasma cutter correctly and not be disappointed.
Here are the main disadvantages of the devices and the method itself:
The best cutting quality is achieved by holding the burner at a 90-degree angle to the surface.
Only expensive models can cut the chamfer at an oblique angle.
This equipment is difficult to heat the metal to perform bending or forging.
The maximum cutting thickness is 100 mm, while flame cutting can cut through 200-300 mm.
The equipment itself is more expensive. You’ll need another compressor. The price of argon is higher than propane or oxygen.
The devices depending on the electrical network.
To work in the field, a gasoline generator is required.
Its power should be high enough to cover the needs of the plasma cutter and compressor.
Types of plasma cutters
Understanding the principle of operation of the plasma cutter and its device, consider the types of equipment.
This will help you determine the details of the selection for specific tasks in production.
Plasma cutters by cutting type
Plasma cutters are manual and automatic.
This is important to consider when choosing the equipment to fit the upcoming processes.
Plasma cutters for manual cutting
They are used for working with small cross-sections of 1-10 mm.
This is true for a garage and a small workshop where doors, gates, wickets, barbecues are made.
It is convenient for them to cut holes, cutouts for locks and hinges, cut blanks for canvases and bent boxes.
More expensive equipment can cut through 10-30 mm.
This expands the scope of use and is suitable for cutting workpieces for subsequent machining in production (making flanges, shafts, cutting pipes, etc.).
Such installations are mobile and convenient.
Plasma cutter for manual cutting.
They are used with cutting heads that can be moved on portal or cantilever type brackets.
They are controlled by CNC.
They can simultaneously cut 2-4 heads at once. Suitable for cutting parts with dimensions from 1×1 to 3×30 m.
They need sufficient space and are difficult to transport.
Plasma cutter for automatic cutting
Custom-made according to the type of gas used
For the operation of the plasma cutter, the air is needed to ionize in the electric arc. Two types of equipment are distinguished here:
Compressed air plasma cutters
Household and semi-professional class.
They are cheaper, easy to operate (only the current is regulated), and universal.
Very small devices are designed for a cut section of up to 10 mm.
More powerful will cope with 12-25 mm.
The main advantage is low-cost maintenance (the price of the nozzles, a one-time purchase of the compressor).
In the future, you will not have to buy anything expensive.
Plasma cutters based on argon, oxygen, nitrogen, or their mixtures
They are used on large plasma cutting machines.
They need long settings, but they are able to perform the cut faster, more accurately, and more difficult.
It is necessary to regularly spend money on the purchase of gas cylinders.
This type is suitable for large enterprises with a large volume of products.
Argon Plasma Cutting Machine
Custom-made according to the type of arc ignition
More plasma cutters are divided according to the method of excitation of the electric arc:
This type of ignition occurs in household inverters.
The nozzle of the plasma torch must touch the product to which the mass is connected.
The simple design of the burner is less likely to break, but the nozzle is more quickly covered with scale.
They form an arc independently when gas is supplied (without touching the product).
This is convenient for frequent movement and performing small cuts. Saves nozzle life and increases productivity.
High frequency (HF).
The most comfortable type of ignition, achieved at the expense of the oscillator.
The arc is excited by a high-frequency pulse, between the cathode and the anode in the nozzle.
When it is brought to the product, it automatically switches to the cutting machine.
The type of ignition is suitable for the precise start of the cut so that there are no electrical traces left on the workpiece.
Custom-made according to the type of cooling
It is used in household and semi-professional models.
The heat from the burner is removed naturally into the surrounding air. Inside, the channels are cooled by the supply of oxygen or inert gas.
In the housing itself, there is a fan, blowing the transformer and the rectifying unit.
During operation, periodic interruptions will be required to avoid melting the nozzle.
Air-cooled plasma cutter
Used on industrial versions of equipment.
The plasma torch has channels through which distilled water with ethyl alcohol circulates with the help of a water pump.
This quickly takes away the heat and allows you to work with the device without interruptions.
It is suitable for large-scale tasks or operations of the plant in two shifts.
How to choose a plasma cutter?
When choosing a plasma cutter, you need to consider several key characteristics.
The thickness of the cut metal
This parameter directly depends on the current (number of amps) generated by the inverter.
If you need to cut black metal, then for every 1 mm of thickness, you will need 4 A of power.
For example, to cut a 7 mm sheet iron, look for a device with a current of at least 30 A.
For non-ferrous alloys, the calculated value is 1 mm=1.5 A.
There is also the concept of finishing cut and maximum.
For example, the first value in the characteristics can be 12 mm, and the second – 18 mm.
This means that with a thickness of up to 12 mm, no subsequent machining is required at all.
It is better to take a plasma cutter with a margin of power so that it does not work constantly at full strength. This will extend its resource.
Type of metal Current required for cutting workpieces with a thickness of 1 mm
Copper, brass, aluminum, copper alloys 6 A
Stainless steel, ferrous metals 4 A
Duration of activation
It means how long the device will be able to work without interruption.
Depends on the power and type of cooling.
For a garage and a small workshop, installations with a PV of 40% are suitable.
For production where plasma cutting of workpieces is often required, choose a PV of 60-80%.
The required compressor power
In order for plasma cutting to be of high quality, a stable air supply from the compressor is necessary.
Its performance should be 20-30% higher than required by the inverter passport.
Buy a compressor with a filter dryer and an oil separator, so that the impurities do not affect the quality of the plasma.
Hose pack length
The plasma torch can have a cable length of 1.5-8 m. When choosing, consider what dimensions of the structures you will have to work with.
The shorter the hose pack, the more often you will have to rearrange the device.
But if it is required for cutting out small parts above the table, then you can save money and buy a plasma torch with a short cable.
The best plasma cutters
After studying the characteristics of the equipment and tips for choosing, we will move on to the rating of the best plasma cutters, based on the reviews of welders.
Perhaps there you will find a suitable device for yourself and go to the store for a specific product.
Aurora PRO AIRHOLD 42 Mosfet
The rating was led by a plasma cutting machine with an affordable price.
Its dimensions are 40x16x30 cm. It is powered by a single-phase 220V network and consumes 6.6 kW.
The maximum current of 40 A allows cutting up to 12 mm thick without subsequent stripping.
The PV is at a maximum of up to 60%. The inverter is suitable for cutting cast iron, alloy, and carbon steel, copper.
To ignite, you need to touch the nozzle on the surface of the part. The equipment weighs 9 kg, so it is not difficult to transport.
Pros of Aurora PRO AIRHOLD 42 Mosfet 16337
- A convenient device with a good build quality.
- Affordable price.
- The nozzle does not wear out for a long time (only turns black).
- User-friendly control panel.
- It is easy to buy consumables.
- The rigid handle on the lid.
- The iron corners are covered with plastic.
Cons Aurora PRO AIRHOLD 42 Mosfet 16337
- Contact type of ignition.
- If you buy a separate burner with an oscillator, there is no standard connector for connection.
- It is sensitive when the mains voltage drops to 190-200 V.
- Over a thickness of 10 mm, the cutting speed drops significantly.
- You need a compressor with a capacity of at least 350 l / min (otherwise it will be enough for 5 cm of cutting and the air will run out).
This plasma cutter is distinguished by a long standard burner with a cable channel of 5 m.
Great for working with large workpieces in production and in the garage.
Judging by the reviews of welders, the device easily ignites an arc in the cold up to -20 degrees.
If you often have to cut metal on the street, then this is the best choice.
Another professional plasma cutter in the rating at an affordable price. It has a maximum current of 40 A, which is enough for a clean cut of 12 mm. It belongs to the semi-professional class. It is powered by 220 V with a power consumption of 5 kW. According to the passport, the compressor capacity of 170 liters of air per minute is required. The PV at the maximum reaches 60%. To excite the arc, you will need to touch the product. It is not difficult to store and transport the inverter due to the dimensions of 44x16x31 cm. The device uses an air cooling type. The housing has numerous holes and a built-in fan.
Advantages of BRIMA CUT-40
- Small weight of 10 kg and a rigid handle.
- Robust steel housing.
- User-friendly control panel.
- Consumables are available.
- The kit already has three nozzles and three electrodes.
- It makes holes through the paint well.
- Cuts up to 3 mm thick very quickly.
- There are almost no slag stains on the “ten”.
Cons of BRIMA CUT-40
- There is no Euro connector for replacing the burner with a higher-end model.
- Contact ignition of an electric arc.
- The nozzle quickly deteriorates.
- The drain from the built-in dehumidifier is located next to the cooling fan (splashes get into it).
- This plasma cutter has a very compact plasma torch.
If you need to dismantle metal structures and climb into narrow places to cut off racks, shelves, or other elements, then this burner is suitable.
The head is equipped with a short ceramic nozzle with an inclination of 100 degrees. Hold the cutter comfortably.
Resanta IPR 40
Next in the ranking is a product from the Latvian brand, assembled in China.
The inverter-type plasma cutter is made in a steel case and is equipped with air cooling.
A pressure gauge is placed on the front side so that the welder does not need to look at the indicators on the compressor.
The plasma torch has a soft clip that makes it easier to hold the start button down during long cuts.
The device is powered by a single-phase network and outputs up to 40 A.
At the same time, 35% of the PV is allowed. You will need a pressure of 5000 bar for a high-quality cut.
The thickness of the clean-cut is 12 mm.
Advantages of Resant IPR 40
- Loops for winding the hose pack.
- Relief on the handle of the plasma torch, which makes it easier to hold and manipulate.
- Steeples current control from 15 to 40 A.
- Built-in pressure gauge for monitoring the system pressure — no need to look at the compressor.
- With a steel thickness of up to 5 mm, it cuts very confidently.
- Any service center has spare parts for it.
Cons of Resent IPR 40
- Relatively high cost.
- The Euro connector is missing.
- The cut quality is worse when the mains voltage drops.
- You need a powerful compressor.
- Sometimes the mass clamp on the product is poorly fixed.
This plasma cutter features a 5-second arc on/off function. This mode is useful for the fast cutting of the mesh.
The welder does not need to press the button often, which saves its resource.
The speed of cutting such materials with an intermittent arc is much higher than if you had to set it on fire every time you hit the thin twigs of the grid.
Blue Weld Prestige Plasma 54 Compressor
Continues the rating of the product from the Italian brand. The plasma cutter has a current range of 7-40 A and is able to cleanly cut metal sections up to 10 mm.
It consumes 4.5 kW, but the welders in the reviews share that the device will be able to function even from a generator with a capacity of 3 kW.
The power supply weighs 16 kg. The length of the plasma torch cable is 4 m.
The unit is not very noisy and is easy to transport. On the dashboard, there is an indication of the mass, network and overheating.
Advantages of Blue Weld Prestige Plasma 54 Compressor
- Ergonomic handle of the burner.
- There are slots for attaching the shoulder strap — you can cut at a height.
- The controls are protected from accidental changes to the settings.
- The lock of the start button is in the clamped position.
- You can lower the current to 7 A to cut carefully tin 0.6-0.8 mm thick.
- The length of the cable package is 4 m.
- The brushless motor of the compressor will last a long time.
Cons Blue Weld Prestige Plasma 54 Compressor
- The burner nozzle is longer than other models.
- There is no rigid handle.
- High cost.
- There is no EURO connector.
- PV 30% – after cutting through 1.5 m, you have to let it cool down for up to 20 minutes.
- Larger dimensions 51x17x34 cm.
The peculiarity of this plasma cutter is already visible from the name. It has a built-in compressor designed specifically for the arc.
By purchasing it, you get everything you need in one package for plasma cutting.
This simplifies transportation and is useful for mobile work (field teams for installation/dismantling on-site, construction of metal structures).
With it, you can even cut off something at a height, because you do not need to drag a compressor or a long hose separately.
Svarog REAL CUT 45 L207
The rating is completed by the model from the manufacturer “Svarog”.
This is a high-quality plasma cutting machine with a power of 4.3 kW, producing 20-45 A.
For optimal operation, a compressor producing 100 liters of air per minute is sufficient.
The inverter uses a pressure of 4 bar to ionize the arc.
The maximum metal cross-section for a clean cut is allowed 12 mm, but welders in the reviews share that they will be able to cut through 15 mm.
The product is equipped with a plasma torch with a 5 m sleeve and a 3 m mass cable.
Pros of Svarog REAL CUT 45 L207 93557
- It can be connected to a small gas generator due to the consumption of 4.3 kW.
- The high legs contribute to the stability of the unit and the passage of air from below for better cooling.
- The corners of the case are protected by rubber pads.
- There is a built-in pressure gauge for monitoring the pressure.
- Clear and smooth cutting line.
- High-frequency ignition for the easy cutting start.
- Rarely goes to the defense.
Cons of Svarog REAL CUT 45 L207 93557
- No slits for the shoulder strap.
- At first, there may be problems with ignition.
- Without a stencil, the flatness of the line suffers.
- A flimsy diffuser on a plasma torch.
his plasma cutter has two features: low weight in relation to power. The weight of the device is 8 kg, which is useful for frequent transportation from object to object.
There are also lighter models, but here the maximum current is 45 A, which not all compact plasma cutters can boast of. This is the best device for construction.