How does a plasma cutter work?

A plasma cutter forces compressed gas through a narrow nozzle bore and electrically ionizes it into plasma — the fourth state of matter. This superheated gas jet (20,000–30,000 °F) melts the metal and the high-velocity stream blows the molten kerf material away, leaving a clean cut edge.

What materials can a plasma cutter cut?

Plasma cutters cut any electrically conductive metal: mild steel, stainless steel, aluminum, copper, brass, and titanium. They cannot cut wood, plastic, concrete, or any non-conductive material, because the workpiece must complete the electrical circuit.

What consumables does a plasma cutter use?

The five core consumables are the electrode, nozzle, swirl ring, shield cap, and retaining cap. Electrode and nozzle wear fastest and should always be replaced together to avoid mismatched wear levels. Swirl ring and retaining cap are replaced less frequently, typically when cut quality degrades and electrode/nozzle replacement does not resolve it.

How many amps do I need to cut 1/4 in. steel?

The general rule is 1 amp per 0.001 in. of material thickness at a comfortable production cut speed. For 1/4 in. (250 thou) mild steel, a 40–50 A unit cuts cleanly at full speed. A 25 A unit can sever 1/4 in. but slowly and with more dross — it is not suitable for production volume at that thickness.

Is plasma cutting better than oxy-fuel?

For conductive metals under approximately 1.5 in. thick, plasma is faster, produces a narrower kerf, cuts non-ferrous metals, and has lower operating costs since no cutting-gas cylinders are required (air-plasma units run on shop air). Oxy-fuel remains preferred for very thick structural steel over 2 in. where plasma equipment cost rises steeply, and in field situations where electricity is unavailable.

Can I use a plasma cutter for CNC cutting?

Yes, provided the unit has a pilot-arc (HF) start system and a compatible machine torch. The Lincoln Tomahawk 1000 is CNC-compatible. Hand-held-only units like the Tomahawk 375 Air and Tomahawk 625 use contact-start technology and are not designed for CNC table use.

What is the difference between drag-tip and standoff cutting?

Drag-tip (drag-cut) technique uses an extended outer shield cap to maintain a fixed standoff distance by resting the torch on the workpiece surface — easy for beginners and works well on material under 1/2 in. Standoff cutting positions the torch a precise distance above the work surface using a guide attachment; it is required for thicker plate where the drag shield would contact molten splash, and for any CNC operation where torch height is servo-controlled.

What causes excessive dross on the bottom of a plasma cut?

The two most common causes are insufficient travel speed and insufficient amperage for the material thickness. Try increasing travel speed first. If dross persists at faster speeds, verify the amperage matches the material thickness. Moisture in the air supply and worn consumables are secondary contributors.

How often should I replace plasma cutter consumables?

Consumable life depends on cut amperage, number of arc starts, air quality, and cut speed rather than a fixed time interval. Inspect the electrode after every 1–2 hours of cutting at high amperage and replace when the hafnium pit depth reaches 1/16 in. Replace the nozzle whenever the electrode is replaced. In production CNC environments, consumable sets are often changed at the start of each shift.

What shade lens do I need for plasma cutting?

AWS and ANSI Z49.1 recommend a shade 5–8 cutting lens for plasma arc cutting. Use shade 5–6 for units under 20 A and shade 7–8 for 20–100 A units. Plasma arcs emit relatively more blue-spectrum and UV radiation than welding arcs, so a standard shade 10 welding lens is unnecessarily dark.

Can a plasma cutter cut stainless steel?

Yes. Plasma cutting stainless steel is one of the process's strengths — unlike oxy-fuel, plasma does not require the metal to oxidize in order to cut. Compressed air plasma works on stainless up to moderate thicknesses. For thinner stainless where HAZ control is critical, nitrogen plasma or a wet-table CNC setup produces cleaner edges and less surface discoloration before final welding or polishing.

What is plasma arc cutting versus plasma welding?

Plasma arc cutting (PAC) uses a high-velocity, constricted plasma jet to melt and eject material, severing the workpiece. Plasma arc welding (PAW) uses a lower-velocity plasma column to fuse metals together. They share the same physics of arc ionization but differ in torch geometry, gas flow rates, and operating intent. Most plasma cutters — including the Lincoln Tomahawk series — are cutting-only units and cannot be used for plasma welding.

Plasma Cutting

WeldingMart's plasma cutting hub is the resource for professionals who need fast, precise cuts on conductive metal — from fabricators trimming structural plate to HVAC contractors cutting ductwork and pipe shops producing tight-tolerance blanks. Plasma cutting is the dominant thermal cutting process for non-ferrous metals, stainless steel, and mild steel plate under 2 inches, offering cut speeds and edge quality that oxy-fuel and mechanical cutting methods can't match at comparable thicknesses. Browse this hub for handheld plasma cutters, CNC-ready machine torches, consumables, and accessories from Lincoln Electric, Hypertherm, and Miller.

Understanding Plasma Cutting

Plasma cutting works by forcing compressed gas (air, nitrogen, or oxygen) through a small nozzle orifice at high velocity, then passing an electric arc through that gas stream. The arc ionizes the gas into plasma — a superheated, electrically conductive state of matter reaching temperatures above 20,000°C — which simultaneously melts the base metal and blows the molten material out of the kerf. The result is a cut that proceeds at speeds dramatically faster than oxy-fuel cutting on most metals, with a narrower kerf and a heat-affected zone (HAZ) significantly smaller than flame cutting.

Unlike oxy-fuel, plasma cutting requires only electrical conductivity in the base metal — not a specific chemistry. This makes it the correct process for aluminum, stainless steel, copper, and other non-ferrous alloys that oxy-fuel cannot cut. Modern inverter-based plasma cutters deliver the cutting arc with high efficiency, enabling compact, portable units that run on standard 120V or 240V power.

When to Use Plasma Cutting

Plasma cutting covers a wide range of applications where speed, material flexibility, or portability is the primary requirement:

Application	Material	Thickness Range	Machine Type
Structural steel fabrication	Mild steel	1/8" – 1-1/2"	High-amperage handheld or CNC
Stainless sheet metal	304/316 SS	16 ga – 1/2"	Mid-range handheld or CNC
Aluminum plate	5052, 6061 aluminum	1/8" – 3/4"	Handheld or CNC
HVAC / ductwork	Galvanized steel	26 ga – 12 ga	Compact handheld unit
CNC table cutting	Mild steel, SS, aluminum	14 ga – 2"	Machine torch, CNC interface
Demolition / salvage	Any conductive metal	Up to rated maximum	Portable handheld unit

Plasma cutting is not the preferred method for non-conductive materials (wood, concrete, composites), for very thick carbon steel where oxy-fuel cutting is more economical, or for precision bevel cuts on heavy plate where machining is required. For those cases, specialized cutting processes or post-cut machining apply.

Key Equipment Categories

Handheld Plasma Cutters

Handheld plasma cutters are the most common configuration for fabrication, maintenance, and repair. The operator guides a torch along a cut line using a straight-edge, template, or circle guide as needed. Modern units range from compact 20-25A machines for thin sheet (up to ~3/8" mild steel) to 80-125A industrial units cutting 1-1/2" or more. Lincoln Electric's Tomahawk and CTARC series, along with Hypertherm's Powermax series, are the benchmark handheld systems.

CNC / Machine Torch Systems

CNC plasma cutting uses a machine torch — a fixed, straight-body torch without the ergonomic grip of a handheld unit — mounted on a CNC cutting table or robot. Machine torches are designed for continuous duty cycles, precise pierce control, and reliable ignition under automated software control. Key specifications for CNC plasma systems include the THC (torch height control) compatibility, pierce capacity, cut speed at rated amperage, and consumable life per set. Hypertherm's XPR series and Lincoln Electric's advanced plasma systems are specifically engineered for CNC table duty with longer consumable life and advanced cut quality at high production rates.

Air Plasma Systems

Most handheld and portable plasma cutters use compressed air as both the plasma gas and shield gas. Air plasma is economical — shop or portable compressors supply the gas — and performs well on mild steel and stainless for general fabrication. Air quality is critical: oil, water, and particulate contamination shorten consumable life and degrade cut quality. A coalescing filter and desiccant dryer upstream of the plasma cutter is standard practice.

High-Definition / Precision Plasma Systems

High-definition plasma systems (Hypertherm's XPR and similar) use advanced gas control — mixing oxygen, nitrogen, and argon in programmable ratios — to produce cut edges approaching laser quality on mild steel plate. These systems (typically 130-400A) are designed for CNC table use in steel service centers and OEM fabrication. Edge squareness and dross levels approach what was previously only achievable with laser cutting, at a fraction of the capital cost on thicker materials.

Choosing the Right Plasma Cutter

Selecting a plasma cutter requires matching the unit to the heaviest material you regularly cut — not just the thickest piece you'll ever attempt:

Amperage and rated cut capacity: Manufacturers specify both a "rated cut" (clean, production-quality cut) and a "severance cut" (maximum thickness the machine can penetrate, with lower quality). For professional work, size to the rated cut capacity, not severance.
Duty cycle: Plasma cutters have a duty cycle specified at their rated amperage. CNC production work demands 100% duty cycle at operating amperage. Handheld repair and fab work tolerates 30-60%. Select accordingly.
Input power: 120V machines cut up to approximately 3/8" mild steel. 240V single-phase machines cover 3/4" to 1". Three-phase machines at 230/460V deliver the highest amperage output for industrial CNC systems.
Air supply requirements: Each machine specifies minimum CFM and PSI requirements. Undersized compressors cause pilot arc failures, poor cut quality, and shortened consumable life. Verify your air supply capacity before purchasing.
CNC compatibility: If CNC table integration is planned, confirm the machine offers a machine interface port (for torch height control communication), a compatible machine torch, and software support from your CNC controller manufacturer.
Consumable cost and availability: Nozzles, electrodes, shields, and swirl rings are ongoing operating expenses. Hypertherm and Lincoln consumables are widely available. Verify availability before committing to a less common brand.

Brands We Carry

WeldingMart is an authorized Lincoln Electric Preferred Dealer. Lincoln's plasma cutter lineup includes the Tomahawk series for handheld shop and field use, and the CTARC series for higher-amperage work. Lincoln plasma cutters are backed by Lincoln's service network and genuine replacement parts.

Hypertherm is the global leader in precision plasma cutting, with the Powermax series covering the full range of handheld and light CNC work (Powermax 30, 45, 65, 85, 105, 125) and the XPR series for high-definition CNC production. Hypertherm consumables feature patented cartridge-style designs in newer models that simplify changeover and improve consistency. WeldingMart stocks Hypertherm consumables for both Powermax and XPR systems.

Miller Electric's Spectrum series provides a reliable alternative for shops standardized on Miller infrastructure, with clean cut quality and straightforward operation.

Consumables & Accessories

Plasma Consumables

Plasma consumables — electrode, nozzle, shield, swirl ring, and retaining cap — are wear items requiring regular inspection and replacement. Electrode erosion (a pit deeper than 1.5mm in the hafnium tip) and nozzle orifice wear are the primary failure modes. Using consumables past their service life damages the torch body. Replace as a matched set when possible; stock one or two spare sets per shift in production environments. Consumables are machine-specific — confirm part numbers before ordering.

Plasma Torches

Torch assemblies are available as handheld torches (with ergonomic grip and trigger) or machine torches (straight-body, for CNC mounting). Torch lead lengths vary from 15 to 50 feet — longer leads add flexibility but increase electrical resistance slightly. Water-cooled torches are available for very high duty cycle production cutting where air-cooled torch bodies overheat. WeldingMart stocks both OEM torch assemblies and compatible aftermarket options for major platforms.

Air Filtration

Proper air quality directly determines consumable life and cut quality. A two-stage filtration system — coalescing filter (removes oil and water aerosols) followed by a desiccant dryer (removes water vapor) — is the minimum professional standard. Inline moisture traps placed close to the plasma cutter provide a final line of defense. Filter elements and desiccant require periodic replacement or regeneration; monitor pressure drops across the filter to determine service intervals.

Guides & Accessories

Straight-edge, circle-cutting, and roller guides attach to the torch shield for consistent standoff and straight cuts. Drag shields allow the torch to be dragged directly on the work surface without a separate guide. Protective gear includes a face shield with shade 5-8 lens, leather gloves, and a leather apron or welding jacket to protect against slag and spatter.

Safety Basics

Plasma cutting produces intense UV/IR radiation, metal fumes, noise, and heavy spatter. Always wear a face shield rated for plasma cutting (shade 5 minimum; shade 8 for higher amperage). Never cut galvanized, zinc-coated, or lead-painted metal without respiratory protection — zinc oxide and lead fumes are acutely toxic. Hearing protection is required at close range, as plasma cutting generates sound levels above 100 dB.

The plasma arc is carried through the workpiece to the work clamp — never position yourself, cables, or flammable materials in the current return path. Molten metal and slag ejected from the kerf can travel up to 15 feet from the cut; clear the area below and around the work. In confined spaces, ensure adequate ventilation or use supplied-air respiratory protection. Never operate plasma equipment in wet conditions or while standing on conductive surfaces without proper insulation.

FAQs

Can plasma cutters cut stainless steel and aluminum?

Yes — plasma cutting works on any electrically conductive metal, including stainless steel, aluminum, copper, and brass. This is one of plasma cutting's primary advantages over oxy-fuel, which only cuts carbon steel efficiently. Cut quality on stainless and aluminum is generally excellent with proper consumables and gas settings. Very thin stainless (under 20 gauge) can be challenging — edge discoloration and heat distortion require careful parameter control.

What air pressure and flow do I need for a plasma cutter?

Requirements vary by machine — check the specifications for your specific unit. As a general rule, handheld plasma cutters in the 40-65A range require 4-6 CFM at 60-90 PSI. Larger machines require proportionally more. Undersupplying air causes pilot arc failures, rough cuts, and rapid consumable wear. A compressor with a tank large enough to maintain consistent pressure throughout a long cut is essential.

How do I know when to replace plasma consumables?

Inspect the electrode and nozzle after every 30-60 arc starts or when cut quality degrades. The electrode is worn when the hafnium pit depth exceeds 1.5mm. The nozzle is worn when the orifice is elongated or shows rounding of the exit bore. Worn consumables produce angled cuts, increased dross, rough edges, and arc instability. Replacing consumables before complete failure protects the torch body and reduces cut rework.

What's the difference between a rated cut and a severance cut?

The rated cut capacity is the maximum material thickness at which the plasma cutter delivers production-quality cuts — clean edges, consistent kerf, low dross. The severance cut capacity is the maximum thickness the machine can pierce through, but with reduced edge quality. For production work, always size to the rated cut. Severance capacity is useful for estimating capability on occasional heavy cuts or demolition work where edge quality is less critical.

Can I use my plasma cutter with a CNC table?

Many mid-range and industrial plasma cutters include a machine interface port that allows the CNC controller to trigger the arc start, receive arc voltage feedback for torch height control, and monitor cut status. Not all machines are CNC-compatible — verify the machine offers a machine torch option and a suitable interface before purchasing for CNC use. Hypertherm's Powermax 65 and above, and Lincoln Electric's CNC-capable units, are commonly used on CNC tables.

Does plasma cutting require a special power outlet?

Compact plasma cutters (under 30A output) often operate on standard 120V household circuits, though a dedicated 20A circuit is recommended to avoid tripping breakers. Mid-range machines (45-65A output) typically require 240V single-phase service. High-amperage machines (80A+) require 240V single-phase or three-phase service. Always check the machine's input power specifications and confirm your electrical panel can supply the required amperage before purchase.

What causes rough or beveled cuts on a plasma cutter?

The most common causes are worn consumables (especially a worn nozzle orifice), incorrect travel speed (too slow causes dross and heat buildup; too fast causes incomplete cut), improper arc voltage or standoff height, and inadequate air supply. CNC users should verify torch height control calibration and consumable condition first. Handheld users should check for consistent standoff distance and verify the air filter is clean and not restricting flow.

Is plasma cutting safe on galvanized steel?

Cutting galvanized steel with plasma produces zinc oxide fumes, which at sufficient exposure levels can cause metal fume fever — flu-like symptoms typically appearing several hours after exposure. Always cut galvanized material outdoors or with high-volume local exhaust ventilation, and use respiratory protection rated for metal oxide fumes (minimum P100 or PAPR). Where possible, strip the coating from the cut area before cutting.

Browse Our Plasma Cutting Collection

Explore plasma cutting equipment and consumables available at WeldingMart:

Lincoln Plasma Cutters — full Lincoln Electric plasma cutter lineup
Plasma Cutters — Lincoln Preferred Dealer — authorized Lincoln Electric plasma cutting systems
Plasma Consumables — electrodes, nozzles, shields, swirl rings for all major brands
Plasma Torches — handheld and machine torch assemblies and replacement leads
Demo Plasma Cutters — inspected demo units at reduced cost
All Plasma & Welding Equipment — full equipment range including plasma cutters