Plasma Cutting 283

“Plasma Cutting” describes plasma cutting equipment and discusses setup and operation procedures for plasma cutting. Plasma cutting is a precise and efficient cutting method that uses an ionized jet of gas to generate a high-temperature cutting arc. It can be performed manually or automated with CNC machines. Plasma cutting systems can also be used to perform gouging and piercing operations.

Plasma cutting is an increasingly affordable and popular method of metal cutting. Plasma cutting balances the lower cost of cutting methods such as oxyfuel cutting with the higher quality of laser cutting. After taking this class, users will be able to describe plasma cutting, gouging, and piercing, and identify the equipment used in plasma cutting. They will also understand basic troubleshooting and safety considerations for plasma cutting, as well as its advantages and disadvantages. This knowledge is essential for making precise, accurate plasma cuts safely and efficiently.

Class Details

Class Name:
Plasma Cutting 283
Number of Lessons:

Class Outline

  • Plasma Cutting
  • Plasma Cutting Machines
  • Plasma Gas
  • Plasma Cutting Torches
  • Plasma Cutting Start Systems
  • Plasma Cutting Systems Review
  • Plasma Cutting Setup
  • Plasma Cutting Operation
  • Cutting Guides
  • Plasma Gouging
  • Plasma Piercing
  • CNC Plasma Cutting
  • Plasma Cutting Processes Review
  • Troubleshooting Plasma Cutting Systems
  • Advantages and Disadvantages of Plasma Cutting
  • Plasma Cutting Safety
  • Final Review


  • Describe plasma cutting.
  • Describe plasma cutting machines.
  • Describe the gas equipment used for plasma cutting.
  • Describe the components of a plasma cutting torch.
  • Describe the types of starters used in plasma cutting systems.
  • Describe setup procedures for plasma cutting.
  • Explain how to perform manual plasma cutting.
  • Describe how cutting guides are used in plasma cutting.
  • Describe plasma gouging.
  • Describe plasma piercing.
  • Describe CNC plasma cutting.
  • Describe basic troubleshooting considerations for plasma cutting.
  • Contrast the advantages and disadvantages of plasma cutting.
  • Describe safety considerations and best practices for plasma cutting.

Job Roles



Vocabulary Term Definition
air compressor A device that increases air pressure by moving ambient air into a closed system. Air compressors can be built-in or external to plasma cutting machines.
alternating current AC. An electrical current that reverses direction at regularly recurring intervals of time. In the United States, alternating current reverses 60 times per second, or 60 Hertz (Hz).
ambient air Air coming from the surrounding environment. An air compressor pressurizes ambient air for use in plasma cutting.
amperage The amount of current flowing in a circuit. Amperage is measured in amperes (A), or amps.
amperes A. A unit of measurement that indicates the amount of current flowing in a circuit. Amperes are also called amps.
arc height control A system that automatically measures and adjusts the length of the cutting arc. Arc height control systems can be added to CNC plasma cutting machines to greatly improve cut quality.
bevels An edge or surface of an object that is set at a sloping angle. Bevels can be difficult to cut.
carbon steel A common metal that is an alloy of iron and carbon. The amount of carbon in a carbon steel determines its hardness.
circuit A controlled path for electricity. Plasma cutting requires a closed electrical circuit that includes a source, path, load, and control.
computer numerical control CNC. A combination of programmable software and hardware that uses mathematical data to control the operation of a machine. Computer numerical control machines are used to carry out various machining operations, including plasma cutting.
condense The process of changing from a gas or vapor into a liquid or solid. Water vapor, or humidity, becomes liquid water when it condenses.
constant current CC. A power supply that maintains a steady flow of current, regardless of fluctuation in voltage. Almost all plasma cutting systems use constant current power sources.
consumables Any part of a plasma cutting machine that wears over time or through usage. Consumables include electrodes, nozzles, and gas distributors.
cubic feet per hour cfh. A measure of the total volume of gas flow per hour in the English system. Cubic feet per hour is used to express the rate of gas delivery to the plasma torch.
cubic meters per hour cmh. A measure of the total volume of gas flow per hour in the metric system. Cubic meters per hour is used to express the rate of gas delivery to the plasma torch.
current The flow of electricity. Current is measured in amperes (A), or amps.
cutting arc A stream of plasma that forms between the torch and workpiece when the electrode ionizes gas pumped into the torch. Cutting arcs, also known as plasma arcs, produce extremely high temperatures that allow them to cut metal workpieces.
cutting guide A device that attaches to the plasma torch in order to restricts its movement and ensure proper cutting. Cutting guides come in a variety of forms such as straight, circular, and bevel.
cutting speed The rate at the plasma cutting torch moves along the workpiece to create a cut. Cutting speed is measured in inches per minute (ipm) or millimeters per minute (mm/min).
darkness rating The amount of shading provided by a filter plate. Darkness ratings range from 1, which offers the least protection, to 14, which offers the greatest protection.
direct current DC. An electrical current that flows in one continuous direction. Direct current is required for all plasma cutting systems.
drag shield A component that can be mounted on the front of a manual plasma torch in order to maintain proper distance from the workpiece. Drag shields, also known as shield cups, must be held in place with retaining caps.
dross A scum formed by oxidation of the workpiece surface that sometimes contains solidified metal. Dross is difficult to remove and indicates a problem with the plasma cutting machine or process.
ductwork A system constructed of thin sheets of metal that is designed to deliver and remove air. Ductwork is used extensively in the heating, ventilation, and air conditioning (HVAC) industry.
duty cycle The amount of time in a ten-minute period that an electrical device can perform at the rated output before it must rest to prevent overheating. Duty cycle ratings are given as a percentage of the ten-minute period.
electric shock The flow of electricity through the body. Severe electric shock can be fatal.
electrical conductivity The ability of a material to act as a medium for conveying electricity. Plasma has high electrical conductivity.
electrode A device in an electrical circuit that conducts electricity. Electrodes in plasma torches usually have an insert in the tip made from metals that have very high melting points, such as tungsten or hafnium.
electrode cable The path used to conduct electricity from the power source to the plasma torch. The electrode cable delivers electric current to the electrode of the torch.
electromagnetic fields An area of force generated by the motion of an electrically energized conductor. The strength of electromagnetic fields depends on the strength of the electrical current.
filter plate The shaded protective lens inside a welding helmet that filters out harmful rays and intense bright light. The amount of shading required for a filter plate depends on the specific procedure.
filters A device that removes contaminants from the air. The filters in an air compressor must be clean and dry for proper operation.
fire-resistant FR. Designed to resist burning and withstand heat. Fire-resistant materials for PPE are rated and must meet specific safety standards.
frequency The rate at which an alternating electrical current changes direction. Frequency is typically measured in Hertz (Hz), or cycles per second.
fuel gases A gas that can store potential energy and release it as thermal energy or that can be used to perform work. Fuel gases are mixed with oxygen to perform oxyfuel processes such as welding and cutting.
fume extractor A device that uses suction to remove gases from the environment. Fume extractors are important to ensure the safety of plasma cutting operators.
fumes Potentially hazardous gases and particulate matter generated by various manufacturing operations. Processes that produce fumes must use proper ventilation.
gas cylinders A metal container used to hold gases under pressure for manufacturing purposes. Gas cylinders are built specifically for each gas and have different properties depending on the gas.
gas distributor A device that centers plasma gas around the electrode and within the nozzle opening of a plasma torch. Gas distributors, or swirl rings, create a vortex of gas.
generator A device that converts mechanical energy to electrical energy. A small generator in the torch is part of the start circuitry for high-frequency start systems.
gouges An indentation or groove. Gouges on a plasma cutting torch's nozzle indicate wear, which can lower cut quality.
gouging Creating a groove in a workpiece or removing unwanted metal such as old welds or imperfections from a workpiece. Plasma cutting systems can be used to perform gouging.
gouging nozzle A component in a plasma torch that directs plasma through a wide opening that allows operators to gouge a workpiece. Gouging nozzles have wider openings to increase the flow of gas used to blow away unwanted metal removed by gouging.
grinding Using an abrasive to wear away at the surface of a workpiece. Grinding is often used to clean contaminants from the surface of a workpiece.
grounding A means of providing a safe alternate path for electricity in case it strays from its intended path. Grounding can prevent high-frequency start systems from interfering with nearby electrical equipment.
heating, ventilation, and air conditioning HVAC. The industry that produces and maintains climate control systems. Heating, ventilation, and air conditioning systems, such as ductwork, are often made with automated plasma cutting systems.
high-frequency start HF start. A plasma arc starting method that uses high-frequency, high-voltage electricity to ignite the plasma arc. High-frequency start systems can cause interference with other electronic devices and are usually only found in older plasma cutting systems.
humidity The presence of water vapor or moisture in the air. Excessive humidity can cause a plasma cutting torch to malfunction.
infrared IR. Invisible rays of light energy emitted by heated objects. Infrared rays can damage vision.
interference The disruption of the normal functioning of an electrical device due to the presence of another device that produces electricity or magnetic fields. Interference can cause machines to malfunction.
inverters A device that greatly increases the frequency of the electricity supplied by the electrical utility. Inverters allow for the use of smaller, lighter transformers resulting in smaller cutting and welding machines.
ionized Negatively or positively charged due to the addition or removal of electrons. When gas is ionized, it becomes plasma.
laser cutting A thermal cutting process that uses a focused beam of coherent, collimated, monochromatic light to sever a workpiece. Laser cutting is usually an automated process that produces intricate and repeatable cuts.
lead A bluish-white metal that is very soft and ductile. Lead produces harmful fumes when it is vaporized.
lift arc start A plasma arc starting method that uses gas pressure to force the electrode and nozzle apart to create a spark that ignites the plasma arc. Lift arc start systems are more commonly used than high-frequency start systems.
malfunction Failure to operate properly. Malfunctions can be hazardous to operators.
nitrogen A colorless, odorless, tasteless gas that naturally makes up 78% of breathable air. Pure nitrogen is used as a plasma gas for some processes.
nozzle A component at the tip of a plasma torch that focuses plasma into a narrow jet and directs it at the workpiece. Nozzles are one of the main consumables in a plasma torch.
nylon A plastic material that is often used to create fibers for synthetic fabrics. Nylon fabrics can melt in the presence of extreme heat.
oxidation A metal's chemical reaction with oxygen. Oxidation can cause tarnish and rust on a metal's surface.
oxyfuel cutting A thermal cutting process that uses a flame produced by a mix of oxygen and a fuel gas. Oxyfuel cutting is less precise than plasma cutting.
oxygen A colorless, odorless, tasteless gas that naturally exists in the atmosphere. Oxygen is often used as a plasma gas for cutting carbon steel.
pacemakers A small medical device that is implanted in the chest to control an abnormal or inconsistent heartbeat. Pacemakers can malfunction around high-frequency starters.
personal protective equipment PPE. Any clothing or device used to minimize exposure to hazards and prevent injury. Personal protective equipment includes welding helmets and fire-resistant clothing.
piercing A metal removal process that creates a hole in a metal workpiece. Plasma cutting systems can be used to perform piercing.
pilot arc An electrical path between the electrode of a plasma torch and the workpiece that establishes the full cutting arc. Pilot arcs can be created by lift arc, high-frequency, and other starting methods.
pitting A form of corrosion that appears as a number of small holes in a material. Pitting on a plasma cutting electrode indicates that the electrode needs to be replaced.
plasma A state of matter created by energizing gas. Plasma is the fourth state of matter and is characterized by its high temperature and electrical conductivity.
plasma arc A stream of plasma that forms between the torch and workpiece when the electrode ionizes gas pumped into the torch. Plasma arcs, also known as cutting arcs, produce extremely high temperatures that allow them to cut metal workpieces.
plasma arc cutting PAC. A thermal cutting process that uses plasma, which is a jet of ionized gas, to cut metal. Plasma arc cutting, or plasma cutting, is a quick process that creates high-quality cuts.
plasma cutting A thermal cutting process that uses plasma, which is a jet of ionized gas, to cut metal. Plasma cutting, or plasma arc cutting (PAC), is a quick process that creates high-quality cuts.
plasma torch The device used to produce the plasma arc and perform the actual cut in plasma cutting. Gas is pumped into the plasma torch and converted to plasma at the tip.
polyester A plastic material that is often used to create fibers for synthetic fabrics. Polyester fabrics can melt in the presence of extreme heat.
power source A device that supplies the electricity needed for cutting. Plasma cutting power sources can be plugged into wall outlets or use mechanical devices like motors or generators to produce electricity.
pressure gauges A device that measures the amount of gas flowing to the torch and displays it on a dial. Pressure gauges allow operators to monitor gas flow and determine when to adjust the regulator.
regulators A device that allows an operator to precisely control the pressure of the gas supplied to the plasma torch. Regulators consist of valves that control gas flow and gauges that measure it.
respiratory Relating to the organs involved in the breathing of air. Respiratory organs include the nose, esophagus, and lungs.
retaining cap A component of a plasma cutting torch that covers the other consumables and holds them in place. Retaining caps are required for certain torch designs and when using a drag shield.
rivets A type of non-threaded fastener that consists of a shank and a head made of deformable material. Rivets are inserted through holes and hammered to create a matching head on the other side of the part.
safety lock A component of a manual plasma torch designed to prevent operators from accidentally pressing the trigger. Safety locks differ between torch models.
shield cup A component that can be mounted on the front of a manual plasma torch in order to maintain proper distance from the workpiece. Shield cups, also known as drag shields, must be held in place with retaining caps.
standoff distance The space that should be left between the plasma torch and the workpiece. Standoff distance influences the quality of the cut and the life of consumables.
start circuitry A system of electrical components that initiate the formation of plasma in a plasma cutting system. The start circuitry's configuration depends on the starting method used.
state of matter The form matter takes, which depends mostly on temperature and pressure. The states of matter are solid, liquid, gas, and plasma.
straight edge A piece of metal with a linear side used to help operators cut straight lines. Straight edges are clamped to the workpiece.
swirl ring A device that centers plasma gas around the electrode and within the nozzle opening of a plasma torch. Swirl rings, or gas distributors, create a vortex of gas.
synthetic An artificial or manufactured material. Synthetic materials like nylon and polyester ignite easily.
tack welds A temporary weld that holds workpieces in proper alignment for a final welding process. Tack welds are also used to aid in preheating.
thermal cutting A cutting process that uses heat to remove metal from a workpiece. Thermal cutting processes include oxyfuel, air carbon arc, plasma arc, and laser beam cutting.
triggers A component on a manual plasma cutting torch that, when pressed, starts the arc. Some triggers have safety locks that must be turned off to allow the arc to start.
ultraviolet UV. Invisible rays of light energy that consists of wavelengths shorter than those of visible violet light. Ultraviolet light can damage vision and burn skin, and long-term exposure can increase the risk of skin cancer.
ventilation A means of providing fresh air. Plasma cutting requires proper ventilation for the safety of the operator.
voltage The electrical force or pressure that causes current to flow in a circuit. Voltage is measured in volts (V).
volts V. A unit of measurement that indicates the amount of electromagnetic force or pressure. Volts indicate voltage.
volume The amount of space that a material or substance occupies. Volume of plasma gases is measured in cubic feet or cubic meters.
vortex A mass of gas or fluid moving in a circular, whirling motion. A vortex usually has a clearly defined center.
water jet cutting A cutting process that uses a powerful, high-velocity stream of water to cut through materials. Water jet cutting processes often use an abrasive material to increase the cutting abilities of the water jet.
welding helmet A piece of personal protective equipment that consists of a hard face-guard and a dark tinted filter plate. Welding helmets protect operators from flying sparks and the intense light of the plasma cutting arc.
work angle The angle formed between the plasma arc and the surface of the workpiece perpendicular to the line of travel. Work angles are measured from the end of the cut.
work cable The path used to conduct electricity from the workpiece back to the power source. The work cable is connected to the workpiece with a work clamp.
work clamp The device used to connect the work cable to the workpiece. Work clamps are usually spring-loaded metal pincers that can fit workpieces of various shapes and sizes.
workpiece A part that is subjected to a manufacturing process such as cutting or welding. Workpieces include any metals or materials undergoing a cutting process.
zinc A bluish-white metal that is corrosion-resistant and has a relatively low melting point. Zinc produces hazardous fumes when exposed to high heat.