Glossary

Ablation
The removal of material from a surface by melting or evaporation.

Absorbance
A measure of a material’s ability to absorb radiant energy such as light.

Active Medium
A collection of atoms or molecules which can be stimulated to emit electromagnetic radiation.

Aperture
A small hole through which electromagnetic radiation such as a laser beam passes.

Assist Gas
A gas such as nitrogen or oxygen, or sometimes one of several inert gases, used to blow molten metals away from the cut.

Attenuation
The reduction in the energy or power of a laser beam due to absorbtion or scattering as it travels through a medium.

Beam
A group of light rays. A beam may be parallel, convergent or divergent.

CAD
Computer Aided Design. Software used to design parts prior to manufacture.

CAM
Computer Aided Manufacture.

CNC
Computer Numerical Control. Use of a computer to control the movements of the laser cutting machine.

CO2 Laser
A laser which uses carbon dioxide gas as its lasing medium, typically with a power of up to 40,000 watts. Can be either continuous wave (CW) or pulsed.

Collimation
A laser beams ability to have a low divergence over distance.

Collimator
A system of two lenses whose separation is the sum of their focal length, which produces a collimated laser beam.

Continuous Wave (CW)
Continuous emission mode of a cutting laser, as opposed to pulsed mode.

Depth of Field
The range at which the focused laser beam works. Dictated by the diameter of the unfocused beam, focal length of the lens and the wavelength of the laser. A bigger focal length produces a larger depth of field.

Divergence
The angle at which the rays of a laser beam spread away from each other.

Drift
Unwanted variations in laser amplitude or frequency.

Dross
A residue which forms on the bottom edge of a laser cut, formed from material which has been melted by the cutting laser solidifying. May be due to use of low quality materials. Increasing gas pressure or using pulsed laser output can reduce dross.

DXF File
Drawing Exchange Format. Export file format originating in AutoCad, which has become a standard CAD file format.

DWG File
AutoCad drawing file format.

Edge Quality
The state of the edge produced by laser cutting, which is determined by the stability of the motion system and the accuracy and control of the cutting laser.

Energy
Measured in Joules, energy is calculated by multiplying the power in Watts by the duration in seconds.

Etching
Marking the surface of the material without cutting through it completely, by using the laser at a lower power setting.

Feed Rate
The speed the cutting head of the laser moves at.
Focal Point
The point at which the light rays refracted by a lens meet, giving the highest concentration of energy

Gas Jet
Gas which blows into the cutting zone to clear away molten materials.
Gas Mix
A mixture of gases such as carbon dioxide, nitrogen and helium. Different laser cutting applications may require the gases to be mixed in different proportions.
Gas Pressure
The pressure of the laser cutting assist gas measured in psi.

Helium-Neon Laser
A laser which uses a mixture of neon and helium as its medium. It produces a visible red laser beam and is typically used to assist alignment of laser optics, measurement and recording.
Hold Tolerance
The variations in a laser cut relative to a specified target value.
Home
A reference point on the laser cutting machine.

IGS File
Standard CAD file format used for 3D or formed components.

Intensity
A measure of the amount or brightness of light energy.

Kerf
The width of the groove made by a laser cutting tool.

Laser
Light Amplification by the Stimulated Emission of Radiation.

Laser Cavity
A laser cavity or laser resonator is the system of optical mirrors, the active medium and pumping system where lasing takes place.

Laser Cutting
A process using an industrial laser to cut metals or other materials in fabrication. Typical materials suitable for laser cutting include aluminium, mild steel or stainless steel.

Laser Fusion Cutting
Laser cutting by melting and blowing with a gas jet. Also known as melt shearing.

Laser Generated Air Contaminants (LGAC)
Laser cutting can produce fumes which may be toxic, and therefore safety precautions may need to be taken.

Laser Oscillation
The buildup of coherent energy caused by the wave bouncing back and forth between the mirrors in the laser cavity.

Lens
An optic that causes light rays to converge to a point by refraction or reflection.

Melt Shearing
Laser cutting by melting, in which the molten material is blown out of the melt zone by a gas jet. Also known as fusion cutting.

Melting Point
The temperature at which a substance changes from a solid to a liquid state.

Micron
One millionth of a metre. Also known as a micrometre.

Monochromatic
Light consisting of only one wavelength.

Moving Optics Laser
A cutting laser in which the workpiece is kept stationary while the cutting head and mirrors move around it.

Moving Workpiece Laser
A cutting laser in which the workpiece is moved around a stationary cutting head.

Multi-Axis Laser Cutting
A process which allows laser cutting of 3D shapes. It is more complex than flatbed laser cutting.

Nozzle
Part of the gas jet which forces the assist gas into a narrow column in order to push molten material through the kerf.

Oxygen Assist Laser
A cutting laser in which oxygen is used as the assist gas. It induces an exothermic reaction, in the material, so that the oxygen does the cutting while the laser beam maintains the reaction.

Photon
A quantum of light energy.

Power Density
Laser output per unit area, measured in W/cm2.

Pulse
A single burst of laser energy, which can achieve higher power than continuous wave lasers.

Pulse Frequency
The number of laser pulses per second, measured in Hz.

Pulse Length
The duration of laser pulses, in fractions of a second.

Pulsed Laser
A laser which cuts using pulses of laser energy, rather than a continuous wave. It is often used for cutting hard materials such as stainless steel.

Reflection
The bouncing of light waves from a surface.

Reflectivity
The measure of the reflection provided by a particular material.

Refraction
The deflection which occurs when a light wave passes from one medium to another at an angle, such as from air to the glass of a lens.

Vapourisation
Conversion of a liquid or solid into a gas. A laser vapourises material as it cuts.

Taper
The difference between the width of the top and the bottom of a laser cut. Generally it is slightly narrower at the bottom than the top.
Thermal Conductivity
Measures a material’s ability to conduct heat energy from one place to another. Materials with a high conductivity are slower and require more energy for laser cutting as energy is dissipated as heat from the cutting zone.