Laser Cutting – a Definition and Jargon Buster

Laser cutting, laser drilling, laser ablation – there are so many different processes that lasers can be applied to that sometimes it is difficult making out the wood from the trees. Here we will try to cut through all the mumbo jumbo, tech talk and general confusion to provide you with a clear description of what laser cutting really is, what it can achieve and some examples of where we can apply it. Next, we will provide a jargon buster to help you navigate through all the confusing tech-talk we sometimes come across.

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Fiber laser CW

Applications of laser cutting

There are many of them, but some of the more common laser cutting applications include:

Metal laser cutting

Metal laser cutting is typically used to cut mild and stainless steels, copper, brass and aluminium. Some uses include components, structural members, and battery electrodes. The process can also cut reflective metals. It is used extensively in the automotive , aerospace, and engineering industries.

Silicon laser cutting

Laser cutting is used widely in the semiconductor industry for separating individual chips from silicon wafers and fabricating solar panels.

Ceramics and other non-metals

Ceramics for the electronics and other industries are often cut using fiber lasers. Other materials include certain plastics, composites, and latex rubber.

Jargon Buster

When reading about laser cutting, you are likely to encounter a great deal of technical speak, which might make you feel left out in the cold. Not any longer – our little jargon buster, while not entirely on a par with the experts, will at least give you some idea what they are talking about. It’s in alphabetic order too.

Ablation

Laser ablation is the removal of material during the cutting process. The process involves using the laser beam to melt and vaporise the material.

Absorbance

Absorbance is a property of the material being cut. Different materials react differently to laser light, and absorbance is a measure of how much of the laser’s energy the specific material takes in or absorbs.

Beam diameter

In simple terms, this is the diameter of the beam, but as the beam’s intensity varies along its cross-section, the beam diameter is the distance along the beam’s width where its intensity reduces by a factor of 0.125 or 0.365 of the peak intensity.

Beam divergence

Beam diameter is a measure of how much the beam spreads out. It is usually given in milliradians.

CNC

This stands for computer numerical control. In laser cutting the workpiece is mounted on a motion table that is controlled by a computer using CAD software. This is known as a CNC machine.

CO2 Laser

CO2 lasers have been and still are used in industry for laser cutting and other purposes. They can be CW (continuous wave) or pulsed and can produce powers in the order of 50 kW. They are less versatile and more difficult to use than fiber lasers.

Collimation

Where the laser beam does not diverge or converge but is passed through a lens to create a consistent parallel beam that does not disperse with distance.

Cut edge

This is the edge of the material that has been cut by the laser. The quality of the cut is often defined by the deformations made on the cut edge.

Cut quality

This is the quality of the cut. Fiber lasers produce high-quality, high speed cuts.

Watch our YouTube video “1.5kW Fiber Laser Cutting 5mm Stainless Steel”

Cutting gas

Laser cutting processes may use various gasses to enable or improve cutting. Typical gasses are argon, nitrogen, oxygen or air, the choice of which depends on the material.

CW

This is short for Continuous Wave. Some fiber lasers use a continuous wave, while others use a pulsed wave. Continuous wave lasers produce a higher power beam and are therefore best suited to cutting, welding and additive manufacturing applications.

Depth of field

This is a feature of the focused beam that is a measure of its working distance. It depends on the laser wavelength, the unfocused beam diameter, and the lens focal length.

Divergence

This is the angle of spread of the laser beam.

Dross

Laser cutting can produce residue on the bottom of the cut. This is formed by melted material that has solidified. Pulsed fiber laser cutting can minimise dross, as can an increased oxygen supply. Some materials, such as poor quality or rusty steel, are more susceptible to dross formation.

Edge quality (edge factor)

This is a measure of the quality of the cut edge, and the edge factor is the amount of deformation. Fiber laser cuts show excellent edge quality with a virtually zero edge factor.

Energy

Laser energy is its power in watts multiplied by its duration. For instance, 10 watts over one second produces 10-watt seconds, in other words, 10 Joules.

Feed rate

This is the speed of the material being cut relative to the laser.

Fiber laser

A fiber laser delivers the laser beam through an optical fiber. The light is created by diodes and amplified by the fiber optic cable. The laser beam emerging from the cable is focused by a lens onto the material being cut.

Focal point

The distance between the lens that focuses the laser beam and the position where the beam has its smallest diameter. It is where the beam has its highest concentration of energy.

Gas jet

This is gas used to blow away waste materials during cutting.

Heat affected zone

During cutting materials such as steel, heat is conducted into the workpiece. This can change material properties and microstructure. The affected region is known as the heat affected zone.

Intensity

The laser beam intensity is the amount of energy divided by time.

Kerf

This is the width of the cut area, in other words, the cut width. It depends on many factors, including the laser properties, the material being cut and the thickness of the workpiece.

Laser

Just in case you’ve forgotten, the word “laser” is short for Light Amplification by Stimulated Emission of Radiation.

Laser oscillation

A fiber laser beam can be oscillated to optimise its cutting and welding properties. This enables a tiny beam to work on larger areas.

Monochromatic

A monochromatic laser is one that has a specific wavelength. Laser beams have a range of wavelengths surrounding a central wavelength.

Multi-axis fiber laser cutting

This uses multiple fiber lasers arranged over different axes to produce three-dimensional cuts. It is controlled using complex CAD/CAM systems.

Power density

This is the laser output per unit area, for instance, watts per square centimeter.

Pulsed laser

A pulsed laser delivers its power in a train of individual pulses. This provides the highest power over the shortest interval and is used to produce bur-free cuts of materials that are more difficult to cut.

Refraction
Laser refraction is the change of angle as a laser passes between dissimilar materials. This happens because the speed of light is different in materials with different refractive indices.

Would you like to learn more?

The guide, albeit brief, should at least give you a deeper insight regarding what laser cutting is all about. But if you would like to dive a little deeper, as we hope you might, then we are more than ready and willing to help you out. Just contact us using the information on the link and ask away. You will find we are more than willing to talk about about laser cutting. It is a subject very close to our hearts.

 

 

Image Credit: Wikipedia

An illustration of refraction at work

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