Oxy-Fuel Cutting (OFC)

• Thermal cutting uses heat to melt and remove material, cutting through a workpiece
• Suitable materials: metals, ceramics, and plastics
• Common methods: oxy-fuel cutting, plasma arc cutting, laser beam cutting, and electron beam cutting

Oxy-Fuel Cutting (OFC)

• OFC, or flame cutting, uses the heat of an oxy-fuel flame to raise metal to its ignition temperature. Afterward, a pure oxygen jet oxidizes the metal, blowing away slag
• Primarily for cutting ferrous metals like steel
• Unsuitable for materials forming a protective oxide layer (e.g., aluminum, stainless steel)
• Process: Metal preheated to ignition temperature (≈871°C for steel) using fuel gas (acetylene, propane, or natural gas) mixed with oxygen
• High-pressure pure oxygen jet directed at the heated area causes rapid oxidation
• Molten metal and slag are blown away, creating a cut
• Equipment: cutting torch, gas cylinders (oxygen and fuel gas), regulators, and hoses
• Advantages: portability, low cost, and ability to cut thick sections
• Limitations: limited to ferrous metals, slower cutting speeds, and wider heat-affected zone (HAZ)

Plasma Arc Cutting (PAC)

• PAC melts and removes material using a high-temperature plasma arc
• Suitable for cutting various metals, including steel, stainless steel, aluminum, and copper
• Plasma is ionized gas capable of conducting electricity
• A plasma arc is created by forcing gas (compressed air, nitrogen, argon, or oxygen) through a constricted nozzle at high speed.
• An electric arc is then introduced, ionizing the gas and creating a high-temperature plasma jet (up to 30,000°C)
• The plasma jet melts the metal, and high-velocity gas blows away the molten material
• Equipment: power supply, plasma torch, gas supply, and work clamp
• Advantages: faster cutting speeds compared to OFC, cuts wide range of metals, narrower HAZ, and less distortion
• Limitations: higher equipment cost, noisy operation, and potential for electrical hazards

Laser Beam Cutting (LBC)

• LBC melts, vaporizes, or burns away material using a focused laser beam
• Cuts various materials: metals, plastics, ceramics, and composites
• A laser beam is a concentrated, coherent light beam
• In LBC, the laser beam focuses on the material surface, delivering high energy to a small area
• The material rapidly heats, causing it to melt, vaporize, or burn away
• Assist gas (oxygen, nitrogen, or argon) often removes molten material and protects the focusing lens
• Laser types: CO2 lasers, Nd:YAG lasers, and fiber lasers
• Equipment: laser source, focusing optics, gas supply, and CNC control system
• Advantages: high precision, narrow kerf width, minimal HAZ, cuts complex shapes, and automation
• Limitations: high equipment cost, limited thickness capability compared to OFC, and potential for fumes and emissions

Electron Beam Cutting (EBC)

• EBC melts and vaporizes material using a high-energy electron beam
• Typically done in a vacuum to prevent electron beam scattering
• Suitable for cutting various metals, including refractory metals and dissimilar metal combinations
• An electron beam generated by an electron gun accelerates to high speeds
• Electromagnetic lenses focus the electron beam onto the material surface
• Kinetic energy of electrons converts to heat upon impact, melting and vaporizing the material
• Vacuum system removes vaporized material
• Equipment: electron gun, electromagnetic lenses, vacuum chamber, and CNC control system
• Advantages: very high precision, narrow kerf width, minimal HAZ, cuts very thick sections and can weld and cut
• Limitations: high equipment cost, vacuum environment requirement, limited to conductive materials, and potential for X-ray radiation

Other Thermal Cutting Methods

• Arc cutting: uses an electric arc to melt the material
• Thermite Cutting: uses the heat generated by a thermite reaction to melt the material
• Hot wire cutting: uses a resistance heated wire to melt through materials