22 Apr What is Laser Marking?

Precision, traceability and durability are essential in industrial manufacturing. Misapplied markings, unclear codes or worn identifiers can lead to production delays and regulatory issues.

Laser marking, also known as laser engraving, creates permanent marks on various materials, and it withstands post-processing for traceability and longevity. Exceptional speed and high contrast make laser technology excellent for engraving demands across industries.

We’ll discuss laser marking’s benefits, its applications and the type of materials it can engrave.

Understanding Laser Marking

Laser marking is a contactless, permanent engraving process that uses a focused beam of light to alter the properties of a material’s surface. The technique modifies the surface through oxidation, carbonization or other reactions.

Laser marking allows manufacturers to apply serial numbers, barcodes and other identifiers onto various materials, and its benefits include:

• Durability: Laser marks resist wear, chemicals and environmental conditions, ensuring long-lasting legibility.
• Precision: High-resolution marking supports complex design, micro-text and small-scale graphics.
• Flexibility: Laser engraving can be applied to carved, irregular or delicate surfaces.
• Speed and automation: Laser systems integrate into production lines, supporting high-volume operations.
• Traceability and compliance: Essential in regulated industries, laser marking ensures parts can be identified and tracked throughout their life cycle.

Laser Marking vs. Laser Etching

Although the terms laser marking and etching are sometimes used interchangeably, they refer to distinct processes with different mechanisms and applications:

• Laser marking alters the surface color or properties of a material. The process is ideal for applications where surface contrast is required, but structural integrity must remain intact.
• Laser etching is shallower and does not change the shape of the material. The method melts the material on the surface, which causes it to expand and take on a rougher texture. It also affects its reflectivity and increases contrast.

Engraving and etching can be used together for additional contrast. For instance, if the bare metal is particularly dark, engraving might not be dark enough to provide the contrast you need for readability. Etching can add lighter markings to the un-engraved portion to increase contrast.

How Does Laser Marking Work?

Laser marking works by directing a focused laser beam onto the material’s surface, inducing a physical or chemical change. The general process involves:

• Design output: A digital design or pattern is uploaded to laser software.
• Laser configuration: Based on the material, operators select appropriate laser parameters, including wavelength, power, pulse frequency and scan speed.
• Beam delivery: Galvanometric mirrors or optical systems direct the laser beam across the surface with high precision.
• Surface interaction: Depending on the laser type and material, the laser oxidizes, converts or changes the surface’s hue through chemical reaction.

Laser Marking Types

Laser engraving uses several techniques to achieve permanent marks:

• Annealing is used with metals and relies on oxidation. The heat from the laser causes molecules under the titanium or stainless steel surface to oxidize or gain electrons, resulting in a change in color on the surface while maintaining the material’s texture and integrity.
• Staining uses the laser energy to create some kind of chemical reaction, such as charring on plastics. The soot that forms when plastic is heated makes a dark mark.
• Carbon migration involves heating the material, which releases gases like hydrogen and oxygen, leaving behind a space with a higher concentration of carbon that appears dark. This method is used on light-colored materials like metals and some polymers.

Laser Marking Applications

Thanks to their dependable, long-lasting results and flexible design capabilities, laser marking machines are used in rugged and delicate applications. Here are some common uses for the technique.

Medical Devices and Supplies

Many medical devices fall under the Food and Drug Administration (FDA) requirements for unique device identifiers (UDIs). UDIs contain information about elements like the manufacturer, serial number and lot or batch number. The UDI must stay readable for the life of the product, so any issues that appear after distribution, such as defects and recalls, can be handled appropriately.

Laser engraving or marking is an excellent fit for many UDIs because it doesn’t wear off over time, even after heavy use and exposure to cleaning supplies. From bedpans and wheelchairs to imaging equipment, cochlear implants and infusion pumps, you’ll find that the impact of laser engraving on medical device compliance is significant.

Aerospace Components

The aerospace industry faces similar requirements from the Federal Aviation Administration (FAA). Many components need to be marked with information like the manufacturer’s name, part number and appropriate certifications. Traceability is essential here, too, but the aerospace industry uses laser engraving because it works on fireproof materials and helps with assembly.

FAA marking requirements demand fireproofing, and engraving information onto fireproof metal is suitable. The information on the part can be used for traceability during recalls or notifications, and to help identify parts during assembly and positioning.

Oil and Gas

Laser marking in the oil and gas industry helps maintain equipment traceability, supports operational safety and ensures regulatory compliance. It allows permanent identification on stainless steel, nickel alloys and coated components, ensuring marks remain readable in various operational conditions.

Laser engraving provides flexibility in coding complex information onto irregular surfaces.

Automotive Components

Traceability is vital for the automotive industry. Parts need to be readily identified during recalls and various warranty processes to ensure safety for the general population. They also need to withstand high heat and the elements.

Laser marking allows manufacturers to mark high-volume components with consistent quality. For materials such as metals, plastics and coated surfaces, lasers create high-contrast marks that remain legible throughout the vehicle’s lifetime.

Laser marking supports brand protection and regulatory compliance by enabling unique identifiers on critical safety and performance components.

Electronics

Circuit boards, connectors and electronic enclosures require intricate, precise engravings for component identification, lot tracking and regulatory compliance. Laser marking is valuable for electronics because it creates detailed alphanumeric codes, 2D data matrix codes and logos on small components.

Military and Defense

Military and defense products need marks that stay clear in harsh environments. Laser marking provides permanent identification that meets stringent military standards (MIL STD), such as MIL STD-130, for component and serial number traceability.

Noncontact laser marking avoids mechanical stress that could compromise safety or performance, and the systems’ adaptability also allows for reconfiguration of different components.

Consumer Goods

Brands use laser marking to differentiate products, improve aesthetics and provide traceable identifiers. For jewelry, phones and laptops, laser engraving delivers precise logos, serial numbers and decorative designs.

Marks are permanent, legible and resistant to wear or cleaning processes. Laser marking’s flexibility allows customization at scale, enabling manufacturers to meet consumer requirements for individuality.

Types of Materials You Can Laser Mark

Laser marking can be used on various materials, including:

• Metals, including stainless steel, aluminum, iron, silver and gold, can be laser marked. Because marking withstands post-treatment, you can process metals for various purposes and appearances. Some alloys require higher energy for surface modification, so consider your metal when choosing a laser machine.
• Plastics like polycarbonate are laser-markable because of their varied colors and physical characteristics.
• Plywood and medium-density fiberboard (MDF) offer fair-colored appearances and react well to marking.
• Glass can be marked for visually appealing effects, ideal for product packaging and promotional materials.
• Leather can be marked quickly using laser marking systems.
• Stone can be laser-marked for outdoor projects, like personalized pavers and garden stones, or ornamental decor.

Types of Laser Machines

There are several types of laser marking machines to choose from, each of which works differently and is best for specific materials and tasks. They differ in how they excite the electrons in the laser to give it the high energy needed for engraving.

Fiber Laser Markers

Fiber laser markers are solid-state lasers that use glass fibers to conduct electricity. Light is initially emitted from a laser diode and moves through a fiber-optic cable, which is outfitted with special components that alter the light. Through several complex processes and exposure to rare earth elements, the light reaches specific wavelengths and higher energy levels. Lenses then alter the shape of the beam to fit the marking application.

MOPA lasers, a type of fiber laser, feature varying pulse durations compared to the fixed pulses of standard fiber lasers. MOPA lasers offer you more control and flexibility, which is particularly beneficial for heat-sensitive materials such as aluminum and plastics. XpressMark and MOPA lasers also typically require a lower investment if you need lasers with lower upfront costs.

Fiber lasers are powerful and can produce minuscule beams for extra precision. They work well with almost any material except wood, are virtually maintenance-free and have long lifespans.

CO2 Laser Markers

CO2 laser markers use gases to transmit electricity and energize the laser. The emitted light moves through glass tubes filled with a gas mixture that includes carbon dioxide (CO2), nitrogen, helium and hydrogen.

On either side of the tube are mirrors, one that’s fully reflective and another that’s partially reflective. As the light bounces between the mirrors, it gains intensity, passing through the partially reflective mirror when it becomes bright enough. It is then focused on the marking surface.

CO2 lasers are robust and can mark through various materials, but they work exceptionally well with non-metals like wood, plastics and leather. You can use them in some food processing applications. Their maintenance requirements are heftier than those of a fiber laser since any problems with the tubes or the mirror system can put the machine out of commission.

Crystal Lasers

These lasers offer extremely high engraving power thanks to certain crystals as solid-state media. These crystals, namely garnet and vanadate, are loaded with various ions that help by imparting specific characteristics on the beam.

Two common options are:

• Nd:YAG: Neodymium-doped yttrium aluminum garnet
• Nd:YVO: Neodymium-doped yttrium ortho-vanadate

These crystals are versatile and allow the laser to reach exceptionally high energy and performance. For instance, they allow vanadate lasers to achieve better beam quality, depth of focus and peak power.

Crystals also make it possible to create lasers with different wavelengths. Some materials respond better to green, blue or ultraviolet wavelengths rather than the typical infrared range. For example, a green laser is commonly used for precious metals like gold and silver, and electrical components, printed circuit boards and other sensitive electronics.

Ultraviolet (UV) Laser Markers

UV lasers use photochemical reactions rather than heat to create permanent, high-contrast marks. The process directly breaks the chemical bonds in the material’s molecules, often referred to as “cold marking.” The laser beam is directed onto a material, where it is absorbed and causes a reaction that permanently alters the surface without melting or burning it.

UV laser markers are best suited for sensitive and reflective materials like plastics, wood, glass and paper, as they offer high precision while maintaining the integrity of the material. The shorter wavelength of UV lasers enables a significantly smaller spot size compared to other lasers, resulting in detailed engravings and markings with fine lines and intricate designs.

These types of lasers are often used in medical technology, electronics and automotive manufacturing applications.

Laser Markers vs. Dot Peening

Laser marking and dot peen marking offer permanent identification solutions, but they operate through different mechanisms and are suited to different industrial requirements.

Dot peening, also called pin stamping or pin marking, uses a small, hard pin or stylus to create indentations on a material’s surface. These marks make the surface rougher and alter its reflectivity.

Here’s a comparison of each method:

• Mark quality: Laser marking provides high-contrast, detailed marks suitable for complex codes, logos and text. The contactless process ensures precision on small or irregular surfaces, and marks are readable under varying light conditions. Dot-peen marks are tactile and robust, and they require specific lighting conditions to read the barcode.
• Maintenance requirements: Dot peen systems involve mechanical contact, meaning that regular replacement is necessary to maintain mark quality. Lasers have minimal moving parts and operate without contact between the machinery and the surface, reducing routine maintenance and the risk of mechanical wear and tear.
• Speed: Laser engraving systems achieve higher throughput because of faster marking cycles and the ability to mark multiple components in sequence. Dot peen machines maneuver at a slower pace for complex patterns or high-volume operations when deep tactile marks are required.
• Material compatibility: Lasers can be configured for a broad range of materials, while dot-peen marking is most effective on harder metals and some rigid plastics.

Laser Marking Machines From Telesis Technologies, Inc.

From simple barcodes to industrial data plates that last for decades, the possibilities for laser marking are endless. Telesis Technologies, Inc. engineers high-quality direct part marking systems in various styles and configurations to meet your project’s needs. We’re your one-stop shop for laser and dot peen marking solutions, including customization, integration and software.

We are the only company in the market offering custom dot peen and laser marking projects designed to integrate with pre-existing production lines or custom specs. With worldwide sales and support, industry certifications and a focus on customer service, we make sure you have everything you need to maintain traceability and compliance. Our products are used by NASA, the Department of War and other federal agencies, so you know you can turn to us for trusted laser marking solutions.

Fill out a contact form today to discuss your application needs with an expert.