Plasma Cutters (LGK Series) — Industrial Air Plasma Cutting Machines 80A–160A
A plasma cutter severs metal by directing a constricted electric arc and a high-velocity gas stream at the workpiece. The arc melts the metal locally and the gas jet blows the molten material clear of the kerf. The proce
The LGK series is BrightWelding's line of air plasma cutting machines, covering 80 A to 160 A across four models. This page explains how the process works, what determines cutting capability and consumable life, how to select a model, and what importers and distributors need to know about specification, certification and ordering.
What Is a Plasma Cutter?
Plasma is the fourth state of matter — distinct from solid, liquid and gas. [source: hypertherm.com] In a plasma cutter, an electric arc is forced through a narrow constriction in the torch, and a gas passing through the same constriction is heated until it ionizes into plasma. The ionized gas becomes electrically conductive and carries the arc current to the workpiece at high velocity.
The practical result is a concentrated, extremely hot cutting arc. Unlike oxy-fuel cutting, which relies on oxidising the metal with a fuel flame, plasma cutting melts the material — so it is not restricted to steels that will oxidise readily. Carbon steel, stainless steel and aluminum can all be cut with the same torch. Mechanized plasma systems can produce detailed cuts in hard-to-reach places on these materials, eliminating the need to reposition large workpieces during cutting. [source: hypertherm.com]
Plasma cutting is widely used as an industrial cutting process, and its combination of cutting speed, running cost and material versatility is what drives that adoption. [source: hypertherm.com] It is the most versatile of the common thermal cutting processes because it works on any electrically conductive material, whereas oxy-fuel cutting is limited largely to carbon steel, low alloy steels and titanium — it is not suitable for non-ferrous metals such as aluminum or stainless. [source: thermacut.com] For those materials, where oxy-fuel is not an option at all, plasma is the preferred cutting technology. [source: voortman.net]
Air plasma cutting machines
The LGK series uses compressed air as the plasma gas. Air plasma cutting machines run from a shop air supply rather than from bottled gases, which simplifies operation and reduces running cost compared with gas-supplied systems. For fabricators cutting carbon steel and stainless in general work, air plasma covers the large majority of requirements.
How Plasma Cutting Works
The sequence inside the torch is worth understanding, because it explains both the consumable wear pattern and the maintenance routine.
1. Pilot arc
When the operator triggers the torch, a low-current pilot arc strikes between the electrode and the nozzle inside the torch head. This pilot arc ionizes the gas passing through, creating a conductive path. During this phase the arc burns against the nozzle, which is a consumable part and gradually erodes as a result. [source: en.wikipedia.org]
2. Transfer to the workpiece
Once the pilot arc is established and the torch is brought close to the work, the arc transfers to the workpiece. Cutting current then flows through the plasma jet.
3. Cutting
The constricted arc melts the metal, and the high-velocity gas stream expels the molten material through the bottom of the cut. The torch is moved along the intended cut line at a speed matched to the material thickness and amperage.
4. Pierce and cut
Cutting from an edge is straightforward. Cutting a hole or starting inside a plate requires a pierce, during which the arc burns through the material before travel begins. Piercing is harder on consumables than straight-line cutting, which is one reason consumable life varies considerably between applications.
Why Plasma Cutting: Compared with Other Processes
| Factor | Plasma | Oxy-fuel | Laser |
|---|---|---|---|
| Materials cut | Any conductive metal — carbon steel, stainless, aluminum | Carbon steel primarily | Carbon steel, stainless, aluminum, others |
| Heat input to workpiece | Concentrated, local | High, wider heat-affected zone | Very low |
| Cut quality on thin sheet | Good | Poor | Excellent |
| Capital cost | Moderate | Low | High |
| Running cost on thick carbon steel | Moderate | Lower | Higher |
| Portability | Handheld units are portable | Portable | Not portable at this power level |
| Typical use | General fabrication, repair, structural steel | Thick carbon steel | High-precision, thin sheet, high volume |
The practical positioning: plasma covers a wide material range at moderate cost with good portability, which makes it the general-purpose cutting process in most fabrication shops. Oxy-fuel retains an advantage on very thick carbon steel where the lower running cost justifies the narrower material range. Laser produces finer cuts and lower heat input but at substantially higher capital cost, and it is not portable at comparable cutting capacities.
Buyers whose work is predominantly thin-sheet precision cutting may find laser systems more suitable; for general fabrication, repair and structural work, plasma is usually the practical choice.
LGK Series Specifications at a Glance
| Model | Rated Current | Input Voltage | Weight | Typical Cutting Range |
|---|---|---|---|---|
| LGK-80 | 80 A | 220 / 380 V | 26.5 kg | Sheet metal, general fabrication |
| LGK-100 | 100 A | 380 V / 3-phase | 26.7 kg | Medium plate, structural work |
| LGK-120 | 120 A | 380 V / 3-phase | 29 kg | Thick plate, heavy fabrication |
| LGK-160 | 160 A | 380 V / 3-phase | 36 kg | Heavy plate, CNC integration |
Shared characteristics: IGBT inverter technology, air plasma operation from a compressed air supply, and a hand torch configuration with CNC integration supported on the higher-output models.
> Note on specifications. Cutting capability depends on material, current and travel speed, and parameters differ by model. Detailed parameter sheets, including cutting capacity tables for specific materials, are available on request.
Model-by-Model Guide
LGK-80 — versatile sheet and plate cutting
The LGK-80 moves to 80 A with dual 220 V / 380 V input options at 26.5 kg. It extends the cutting range beyond the 60 A model while retaining a comparatively portable form factor. For shops whose work spans thin sheet through to medium plate, this is frequently the entry point at which a single machine covers most of the cutting work.
LGK-100 — medium plate and structural work
The LGK-100 delivers 100 A from three-phase 380 V input at 26.7 kg, targeting medium plate, structural steel cutting and general fabrication. The move to three-phase input reflects the higher current draw and the shop-installation context these machines are normally used in.
LGK-120 — thick plate and heavy fabrication
At 120 A and 25 kg, the LGK-120 is specified for thicker plate and heavier fabrication work. Shops cutting structural sections and thick plate on a regular basis typically select at this level or above, where the higher current supports faster travel speeds on the same thickness and cleaner cuts on heavier sections.
LGK-160 — heavy plate and CNC integration
The LGK-160 delivers 160 A at 36 kg on three-phase input. It is intended for heavy plate work and for integration with CNC cutting tables, where the machine operates as the power source for a mechanized system. Buyers planning CNC integration should confirm the interface requirements for their table controller against the machine at order stage.
Cut Thickness and Current
The relationship between amperage and cutting capability is the specification buyers ask about most often, and it is also the one most often over-simplified.
What governs cutting capability
Cutting capacity is not a single number per machine. It depends on the combination of:
- Material — carbon steel cuts differently from stainless or aluminum at the same thickness
- Current — higher amperage supports thicker material and faster travel
- Travel speed — running slower on a given thickness produces a cleaner cut up to a point, then produces excess heat and dross
- Gas supply — air pressure and flow must be maintained for consistent results
- Consumable condition — a worn electrode or nozzle degrades cut quality before it fails outright
Rated versus maximum cut
Plasma machine specifications normally distinguish between a rated cutting thickness — the thickness at which a clean, production-quality cut is achievable at recommended speed — and a maximum severance thickness, at which the material can be separated but cut quality is not maintained. Quotations that quote a single figure without stating which it is are difficult to compare. Our technical documentation lists both where applicable, and parameter sheets for specific models are available on request.
Practical guidance
Rather than scaling thickness to amperage by rule of thumb, the more reliable approach for a buyer is to state the materials and thicknesses the machine must cover, and to have the required current confirmed against those specifics. A machine that spends most of its working life near its maximum cutting thickness will consume consumables faster and cut more slowly than one operating within its comfortable range.
Consumables: Electrodes, Nozzles and Life
Plasma cutting consumables are wear items, and their cost varies with application. Understanding what wears and why helps buyers plan running costs.
Electrode
The electrode carries the arc and erodes during use. Plasma cutting electrodes are typically composed of two metals: a copper shell with a hafnium insert. [source: en.wikipedia.org] The copper conducts heat away; the hafnium insert provides the emissive surface that withstands the arc attachment point. Hafnium is used because it resists the arc's thermal load far better than copper alone.
Nozzle
The nozzle constricts the plasma and shapes the jet. It is exposed to the pilot arc at each start, and erodes progressively as a result. [source: en.wikipedia.org] Nozzle condition directly affects cut quality: a worn nozzle produces a wider, less defined kerf.
Shield
The shield cap protects the nozzle and controls the secondary gas flow around the cutting jet. It is a lower-wear item than the electrode or nozzle but is frequently replaced together with them.
What shortens consumable life
- Piercing rather than edge-starting, particularly on thick material
- Excessive pilot arc time — prolonged pilot operation before transfer erodes the nozzle [source: en.wikipedia.org]
- Incorrect air pressure or moisture — wet or low-pressure air accelerates wear
- Running above rated thickness — pushing the machine beyond its comfortable range
- Standoff variation — inconsistent torch height affects both cut quality and wear
Spare parts planning
For distributors and for shops running plasma cutting continuously, keeping a consumable stock on hand avoids downtime. The consumable set — electrode, nozzle and shield — is normally quoted as a kit, and buyers specifying a machine for production use typically order a starter supply alongside it. Spare parts are available directly and through our dealer network.
Cutting Gases
Air plasma machines use compressed air as the plasma gas, with the same air supply typically providing the secondary flow.
Air quality
Compressed air for plasma cutting should be dry and free of oil. Moisture in the air supply is one of the more common causes of poor cut quality and accelerated consumable wear, and a filter-regulator or air dryer is normally specified as part of a complete installation. Air pressure and flow must be maintained within the machine's specified range; both low pressure and excess moisture degrade performance before they cause an outright fault.
Alternative gases
Plasma systems can also run on other gases: by reducing the amperage and selecting a different gas, machines can produce a variety of marks and cut types using the existing cutting system. [source: hypertherm.com] The four main plasma cutting gases are compressed air, oxygen, nitrogen and argon-hydrogen mixtures; where argon is used it appears as a blend rather than on its own, and an argon-hydrogen mix is the choice for thick stainless steel and aluminum and for plasma gouging. [source: westermans.com] [source: lindedirect.com] The LGK series is configured for air plasma operation from a compressed air supply, which is the configuration that covers general fabrication work at the lowest running cost.
Handheld and CNC Operation
Handheld cutting
With a hand torch, the operator controls standoff, travel speed and cut path manually. Handheld cutting is the norm for repair work, cutting structural sections to length, demolition, and any application where the material cannot be brought to a table. The LGK-80, being lighter and running on more flexible input supplies, is typically the models specified for handheld field use.
CNC table integration
Mechanized plasma cutting mounts the torch on a gantry or table and moves it under program control. This produces consistent travel speed, consistent standoff, and repeatable parts — the characteristics that manual cutting cannot match. Mechanized plasma systems make detailed cuts in hard-to-reach places on carbon steel, stainless steel and aluminum. [source: hypertherm.com]
For shops moving to CNC, the machine's role changes from a tool to a power source within a system. The selection criteria also change: the requirements become steady output at the duty cycle the table demands, a compatible interface for torch height control, and a torch configuration suited to machine mounting.
Which to specify
| Working pattern | Configuration |
|---|---|
| Repair, structural cutting to length, site work | Handheld torch |
| Repeat parts, consistent cut quality, volume | CNC table integration |
| Mixed shop with occasional part cutting | Handheld machine, with CNC option available |
Buyers planning to add a table later should confirm CNC compatibility at the point of machine purchase rather than assuming it.
Terminology and Configuration Questions Buyers Raise
Cutting equipment is described inconsistently across catalogues and marketplaces, which produces a steady stream of specification questions. The following covers the terms that most often need clarifying.
"Air plasma cutter" — what it means
An air plasma cutter is a plasma cutting machine that uses compressed air as the plasma gas, rather than bottled nitrogen, oxygen or argon-hydrogen mixtures. All models in the LGK range are air plasma cutters. The distinction matters commercially: an air plasma machine requires only a compressor, whereas gas-supplied systems require cylinder supply arrangements. For general fabrication cutting carbon steel, stainless and aluminum, air plasma covers the large majority of work at lower running cost.
"Plasma cutter welding machine" — two different products
This phrase is used in two ways, and the ambiguity causes genuine procurement problems.
In some catalogues it describes a multi-process welding machine that also offers plasma cutting — a welding power source with a cutting function added. These machines are typically limited in cutting capacity, because the cutting function is secondary to the welding function.
In other catalogues — and in most buyer enquiries — it means a dedicated plasma cutting machine purchased from a welding equipment supplier. The LGK series is a dedicated cutting line: it cuts, and it does not weld.
Buyers whose primary requirement is cutting should specify a dedicated machine. Where cutting is occasional and welding is the main work, a multi-process unit may be adequate — but the cutting capacity should be verified against the intended material thickness rather than assumed from the presence of a cutting mode.
"CNC plasma cutter" — machine or system?
A CNC plasma cutter is a plasma cutting system integrated with a computer-controlled gantry or table. The machine tool comprises the table, the controller, the torch height control and the plasma power source. When buyers ask for a CNC plasma cutter, the scope of supply matters: some quotations cover only the power source for an existing table, others cover a complete system.
Our scope is the power source. Buyers integrating with a table should confirm the interface requirements of their controller — torch height control signals, start and stop, and voltage divider output — against the machine specification at order stage.
Voltage: 220 V or 380 V?
This is the most frequently asked configuration question, and the answer depends on the point of use rather than on preference.
- LGK-80 accepts either 220 V or 380 V depending on configuration.
- LGK-100 and above are three-phase 380 V machines, reflecting their higher current draw.
Buyers should confirm the supply available where the machine will actually be used, not merely at the building's main panel. A three-phase machine installed where only single-phase is available cannot be operated with an adapter, and the reverse mistake — specifying a single-phase machine for a shop that could support three-phase — limits cutting capacity unnecessarily.
For export orders, the voltage configuration is confirmed at order stage alongside the destination market.
Cut Quality: What Affects It
Four characteristics determine whether a plasma cut meets specification, and all four are influenced by settings rather than by the machine alone.
Kerf width — the width of material removed by the cut. Kerf narrows with correct travel speed and a good nozzle, and widens as the nozzle wears.
Dross — molten material that resolidifies on the underside of the cut instead of being blown clear. Low-speed dross (from travelling too slowly) and high-speed dross (from travelling too fast) look different but both indicate the speed is outside the correct window for the material and current.
Bevel angle — the cut edge is not perfectly square in plasma cutting; a small angle is normal. Excessive bevel typically indicates consumable wear, incorrect standoff, or travel speed outside the recommended range.
Heat-affected zone — the region of the parent metal whose structure has been altered by cutting heat. Plasma cutting produces a narrower heat-affected zone than oxy-fuel, which reduces distortion on thin material.
Because all four are affected by travel speed, air quality and consumable condition, the practical control levers are consistent parameters, a clean air supply, and replacing consumables before they degrade cut quality — not only when they fail. Keeping a written record of the settings that produced an acceptable cut on a given material and thickness means the next job starts from a known point rather than from trial and error, which matters most where several operators share the same machine across different shifts.
Applications
Sheet metal and HVAC
Ductwork, panels, brackets and general sheet work are the core application for the smaller models. Cutting speed and low setup time make plasma economical for one-off parts as well as batches.
Structural steel fabrication
Cutting beams, plate and sections to length is a standard fabrication task. The LGK-100 through LGK-160 models cover the plate thicknesses commonly encountered in structural work.
Automotive and vehicle repair
Piping and mechanical contracting
Pipe cutting, support fabrication and mechanical installation work use handheld plasma machines where portability and the ability to cut stainless and carbon steel with the same torch matter.
Demolition and salvage
Dismantling steel structures requires a machine that can cut thick sections quickly and operate on site. Air plasma machines remove the fuel gas and oxygen cylinder logistics that oxy-fuel cutting requires.
CNC part production
Shops producing repeat parts — brackets, plates, gussets — use CNC table integration. Cut consistency, nesting efficiency and repeatability are the drivers rather than portability.
Certifications and Export Compliance
BrightWelding products carry CE certification across the product lines, with CSA certification available for North American markets. The company operates an ISO 9001 quality management system. [source: brightwelding.com]
Documentation accompanying shipments typically includes a Certificate of Origin (Form E, Form F or general, depending on destination), a CE Declaration of Conformity, a commercial invoice and packing list in English, and the bill of lading or airway bill. Test reports and inspection certificates are supplied on request. [source: brightwelding.com]
Our Certifications page lists the documentation available, and the Welding Machine Certifications guide explains the applicable standards for arc and cutting equipment.
OEM and Private Label Options
The LGK range is available with OEM and private-label customization for distributors and brand owners. [source: brightwelding.com]
Customization scope typically covers:
- Body colour matched to the distributor's brand
- Control panel overlay and layout
- Logo and labelling on machine and packaging
- Voltage configuration for the destination market
Minimum order quantity starts at 20 units for mixed models, with trial orders accepted at as few as 5 units per model and volume pricing at container quantities. The OEM Service page describes the process from artwork through first-article approval.
Ordering, Lead Time and Shipping
Order process. Orders begin with a specification: model, quantity, voltage configuration, torch configuration (handheld or machine torch), whether CNC compatibility is required, and any OEM requirements.
Lead time. Standard production lead time runs 15 to 30 days depending on order size. Sea freight transit typically adds 15 to 35 days depending on destination; air freight is available for urgent orders. [source: brightwelding.com]
Payment terms. Standard first-order terms are a 30% deposit by T/T on order confirmation with the 70% balance before shipment. Letters of credit at sight and Alibaba Trade Assurance are accepted for eligible orders, and terms are negotiable for established customers. [source: brightwelding.com]
Packaging. Machines ship in export-grade corrugated cartons with high-density foam inserts, loaded onto fumigated ISPM 15-compliant wooden pallets, stretch-wrapped and strapped for container stability. [source: brightwelding.com]
Consumables. A starter consumable set is available with machine orders, and ongoing consumable supply is supported through our dealer network.
Frequently Asked Questions
What is a plasma cutter good for? Cutting any electrically conductive metal — carbon steel, stainless steel and aluminum among them. Its main uses are general fabrication, cutting structural sections to length, sheet metal work, repair and demolition. [source: hypertherm.com]
What gas does a plasma cutter use? The LGK series uses compressed air. Plasma systems can also operate on other gases — reducing amperage and selecting a different gas allows different marks and cut types from the same system. The main alternatives are oxygen, nitrogen and argon-hydrogen mixtures, selected against the material and thickness being cut. [source: hypertherm.com] [source: westermans.com]
What thickness can a plasma cutter cut? Capability depends on material, current, travel speed and consumable condition rather than on a single figure. Specifications normally distinguish a rated cutting thickness from a maximum severance thickness. State the materials and thicknesses you need to cover and have the current confirmed against them.
What are the downsides of plasma cutting? The cut edge is not perfectly square — a small bevel is inherent to the process. Consumables wear and require replacement, and air quality directly affects both cut quality and consumable life. On very thick carbon steel, oxy-fuel can be more economical.
What is the difference between a plasma cutter and a welding machine? They serve different functions: a plasma cutter severs metal, while a welding machine joins it. Both use an electric arc. Some multi-process welding machines also offer plasma cutting capability; the LGK series is a dedicated cutting line.
How long do consumables last? Consumable life varies widely with application — piercing rather than edge-starting, air quality, and how close to the machine's limits it operates all affect it. The pilot arc burns against the nozzle at each start, which is a primary wear mechanism. [source: en.wikipedia.org]
Can I use a plasma cutter on stainless steel and aluminum? Yes. Plasma cutting is not restricted to ferrous material, which is one of its advantages over oxy-fuel cutting. [source: hypertherm.com]
What size air compressor do I need? Air pressure and flow must meet the machine's specified requirement, and the air should be dry and oil-free. Confirm the requirement against the specific model — requirements differ across the range.
Can a plasma cutter be used with a CNC table? Yes. The higher-output models in the LGK range support CNC integration. Buyers planning table integration should confirm interface and torch configuration requirements at order stage.
What causes dross on the bottom of a cut? Travel speed outside the correct window for the material and current — both too slow and too fast produce dross, though of different appearance. Consumable wear and incorrect standoff also contribute.
What is the difference between handheld and machine torch? A handheld torch is designed to be moved by an operator; a machine torch mounts on a CNC gantry or table and is moved under program control. The two are specified separately at order stage.
What is the minimum order quantity? Standard MOQ is 20 units for mixed models, with trial orders accepted at as few as 5 units per model. [source: brightwelding.com]
How long is the warranty? All machines carry a one-year free warranty. After that period spare parts are supplied at cost, with local repair support through our dealer network in key markets. [source: brightwelding.com]
Request a Quotation
Tell us the models, quantities, voltage configuration and torch requirements you need, and we will return a quotation with lead time and shipping options. For cutting capacity questions, our engineering team can confirm the current required against your materials and thicknesses.
Request a Quote · Download specifications · View OEM options
Models in this series
- LGK-100 100A Heavy-Duty Plasma Cutting Machine
- LGK-120 120A High-Power Plasma Cutter
- LGK-160 160A Industrial Plasma Cutting System
- LGK-60 60A Air Plasma Cutter
- LGK-80 80A Industrial Plasma Cutter
Each model page lists rated output, input requirements, duty cycle and the applications the machine is specified for.