What Is Laser Marking?

14 Aug What Is Laser Marking?

Laser cutting and engraving (also laser etching) are the most common terms used when referring to modifying the surface of a material with a laser.

Marking is less frequently mentioned, but just as effective for many purposes. It is one of many uses for industrial lasers as well as cutting and engraving.

What Is Laser Marking?

Laser marking uses a focused laser beam to create permanent marks on a material’s surface without removing any material. This process changes the colour or appearance of the surface and is commonly used for marking serial numbers, logos, and barcodes on various materials.

The main difference between laser marking and laser engraving is that marking does not remove areas of the material. Instead, the laser beam heats the surface causing its colour to alter, permanently marking the material.

As with any laser application, this is much more effective than manually modifying the material.

4 Main Types Of Laser Marking Methods

There are multiple ways to mark a variety of material surfaces, the following methods are the most common, and each form is achievable with any of our laser engravers.

The versatility of these machines means you can change the settings to achieve completely different results. These variations include:

• Annealing – A process in which the beam heats up the surface enough to finely oxidise it. The process is used on metals containing carbon, e.g. titanium.
• Carbon Migration – Heat from the laser raises carbon molecules to the material surface resulting in a dark marking. This is another variation suitable for only carbon-containing metals.
• Foaming – Foaming is a variation used on plastics, particularly dark ones. The focused material is melted creating a foamy appearance that remains sealed once the material has cooled down. This reduces the density of the focused area and, therefore allows light to pass through it, leaving a light, smooth marking.
• Colouration/Discolouration Marking – The laser heats the material enough to oxidise its surface, altering its colour. This laser marking process depends on the type and colour of the material used, but can leave a contrasting finish on any colour material.

Comprehensive Materials Processing provides scientific background on various types of marking.

What Materials Can You Mark With A Laser Marker?

It is important to note, that unlike fiber laser engraving machines and fiber laser cutters, CO2 lasers aren’t designed to cut, engrave or mark metals.

However, you can mark coated metals with a CO2 machine, removing the coating to reveal the underlying metal. This is a very common way of personalising objects.

You can also add a marking compound to the material to achieve a similar finish. This is a fairly simple method, yet leaves a stunning, bright finish.

MarkSolid Spray and Paste is designed specifically for this application.

To use it, apply the solution, allow 15-20 minutes to dry, laser the material, and wipe off the excess compound with a cloth and an IPA solution.

Materials That Can Be Marked With A Laser Include:

• Coated metals
• Uncoated metals (CO2 lasers require a marking compound to be applied, such as MarkSolid)
• Leather
• Glass
• Silicone
• Ceramics
• Card
• Fabrics

Types Of Laser Marking Machines

There are various types of laser marking machines designed for different applications.

Each type is ideal for specific materials and operations. We’ll explore the two most common types: CO2 laser markers and fiber laser markers.

This comparison will help you decide between a fiber laser and a CO2 laser for your needs.

CO2 Laser Markers

CO2 laser markers are commonly used for engraving non-metal surfaces. These machines utilize a sealed-tube system with light beams to create precise markings.

They are popular for product recognition, logos, date stamping, and more. CO2 lasers are excellent for engraving serial numbers, logos, matrix codes and barcodes on a variety of products including electrical appliances, food and medical packaging, and electronic components.

Applications

The wavelength of CO2 lasers is particularly effective on organic materials like paper, wood, and a wide range of plastics. They are also suitable for marking leather.

Pros:

• Ideal for coated metals such as painted brass and anodised aluminium.
• Versatile across various non-metal materials, beneficial for industries ranging from electronics to medical and packaging.

Cons:

• Expensive to engrave uncoated metals with a marking compound
• Galvo CO2 machines are fast but have a limited engraving area. Regular CO2 engraving and cutting machines have much larger working areas but the engraving process is much slower than a galvo engraver.

Fiber Laser Engravers/Markers

Fiber laser engravers such as the Laserscript LSE110 have gained popularity due to their power and efficiency. These solid-state lasers typically range from 20 to 50 watts and use ytterbium to generate photons at a wavelength of around 1,090 nm.

This makes them ideal for marking metal materials.

Applications

Fiber laser markers excel at depth engraving and etching, especially on harder metals. Their small spot sizes allow for high-resolution marking, making them suitable for small-component batch markings.

Pros

• Highly versatile and efficient, offering faster marking speeds.
• No consumables are required, with economic power usage and minimal maintenance.
• Excellent beam quality with high monochromatic filtration for varying power outputs.

Cons

• May not be as effective on materials with high reflectivity.
• Limited ability to create deep engravings on certain metals.

Other Laser Marking Machines

In addition to CO2 and fiber lasers, other laser marking technologies offer excellent results for specific applications.

Nd Laser Markers

Nd laser markers are compact and lightweight, known for marking thin sheets of metal without causing warping or distortion. They are widely used for small, precise markings on materials such as aluminum, steel, and other plated metals.

Green Laser Markers

Green laser markers operate in the green visible light spectrum (532 nm) with power levels ranging from 5 to 10 watts. They are designed for marking highly reflective materials and are ideal for sensitive substrates like silicon wafers.

Green lasers exhibit high precision and reduced thermal impact, making them suitable for soft plastics, circuit chips, and PCB boards.

UV Laser Markers

UV lasers, with a wavelength of 355 nm, are known for their high absorption rate and cold marking capabilities, which minimise heat stress on the material. They are perfect for marking plastics, glass, and ceramics. UV lasers provide high-quality micro-marking for electronic components and medical equipment.

Examples Of Laser Marking Applications

There are many applications for marking, depending on your requirements. One of the most popular is text and numbers on a range of materials.

The precision of marking is perfect for serial and batch numbers, bar codes, etc.

They have no problem producing letters and numbers easily readable to the human eye, and can even create lettering so small it’s only recognised with magnifying equipment or automated technology.

‘Night and day marking’ is another widely used application. This allows material markings to be seen in both light and dark conditions (with backlighting), as used in laptop keyboards, car dashboards and drinks machines.

Benefits Of Laser Marking

• Extremely high production speed (up to 10x faster than CO2 laser cutters can achieve).
• The structural integrity of the lasered material isn’t hindered as the change is minuscule.
• The nature of the process minimises waste and mess.
• The use of codes is extremely useful for traceability and accountability.
• The finish is permanent and highly resistant to fading due to wear.

Why Choose HPC?

All of our laser engraving and marking machines are supplied with either EZCAD or Lightburn software packages.

Each program offers a creative platform to either import externally created design files or to produce designs from within the software.

As with the entire HPC Laser product range, we offer highly competitive prices, business and personal finance solutions. As well as delivery, installation and training from our nationwide team of highly experienced engineers. Learn more about why you should choose HPC laser for your next purchase.

Purchase of a HPC laser engraving machine entitles you to free of charge lifetime access to our highly rated e-mail and telephone technical support, meaning help is always close at hand if you are having problems.

Get in touch with our team of UK based experts today to discuss your needs or call +44 1422 310800

Summary

Laser marking, engraving, and cutting are key applications of industrial lasers, with each process offering unique benefits.

Laser marking, unlike engraving, does not remove material but alters its colour through various methods like annealing, carbon migration, foaming, and colour marking.

While CO2 lasers are effective for non-metal materials and require a marking compound for metals, fiber lasers excel in marking and engraving metals with high precision and speed.

Other specialized lasers, such as Nd, green, and UV lasers, cater to specific materials and applications.

Overall, laser marking offers advantages like high speed, minimal waste, and durable, permanent markings, making it ideal for a wide range of industrial uses.