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Why Choose Laser Marking for Traceability?

authorIcon By Olivier Proulx on July 24, 2024 topicIcon Laser Marking

Today, laser marking is the first choice when manufacturers need to improve their traceability capabilities. Fiber laser technology is recognized as the best option when it comes to permanent markings, high-contrast codes, post-process resistance, and ease of integration.

In this article, we are going to explain why laser marking technology has earned this level of recognition for traceability.

Table of Contents

What Is Laser Marking and How Does it Work?

 

Laser marking is a process that uses a highly focused beam of light to create permanent marks on a surface. For example, our lasers produce laser beams with a diameter (spot size) as small as 0.075 mm and even smaller, depending on the optical configuration used for the application. When energy is focused on such a small area, it’s possible to mark the surface with extreme precision.

Laser marking can be used on all types of materials, including metals, plastics, ceramics, glass, wood, paper, and composites.

During laser marking, the laser beam is controlled using ultra-fast mirrors (galvo scanners) to create identifiers with the desired size, depth, and contrast. Identifiers can include text, common 1D barcodes, serial numbers, and batch numbers. They can also include 2D barcodes like quick response codes (QR codes) and data matrix codes (DMCs).

If you want to learn more about the different types of barcodes and how to best use them with laser marking, you can download our guide on how barcodes work.

What Are the Benefits of Laser Marking for Traceability?

Create Permanent Markings

Laser marking creates markings that permanently alter the surface of materials, either by digging into the material (laser engraving), changing the texture of the micro surface (laser etching), or inserting chemical changes under the surface (laser annealing).

Permanent markings are needed to achieve what is called “cradle-to-grave traceability”, or complete traceability. It’s the ability to track a product and all the components used to make it from its creation through its entire life and disposal. It’s a concept used to regulate many industries that are held accountable by government organizations, including industries like automotive, aerospace, medical, and food & beverage.

With today’s traceability requirements, an increasing number of manufacturers need to implement complete traceability to better identify defects, diminish the cost of recalls, and reach consumers affected by a recall.

Older marking technologies create permanent markings using hard materials to indent the surface, like dot peen marking, scribbling, and pin stamping. These are the technologies that laser marking competes with.

Many other methods do not create permanent markings and cannot be used to meet complete traceability requirements. For example, printed labels and plates can fall off, and inkjet printing can be removed by chemicals and abrasives.

Generate High-Contrast Identifiers

A good contrast is one of the most important factors to ensure the accuracy and consistency of barcodes. Laser marking can create black and white markings—the best contrast possible. This is done by changing the texture of the surface to control how light is reflected.

How Laser Marking Changes Surface Texture to Create Contrast

Lines show small changes in surface roughness, causing diffuse reflections, or reflections of the lines in all directions.

Light is scattered in multiple directions due to low surface roughness, creating white areas.

A line represents a ray of light that is trapped in the chaotic surface roughness when it is reflected on the surface, creating black

Light is trapped in high roughness areas, creating black marks.

Mark Moving Parts

 

Lasers can mark codes on parts while they are moving on conveyors. This technology is called “marking on the fly”. With it, traceability operations can be integrated directly in the production line without affecting cycle time, as conveyors don’t need to be stopped for the marking operation.

To mark on the fly, the laser needs to be supplied with the conveyor’s encoder signal. This provides the laser with all the information needed to actively compensate for the part’s movement during laser marking.

At Laserax, we’ve even developed the technology to mark parts moving on a curved line on carousel-like conveyors. This feature is a game changer for clients trying to optimize their plant layout.

Maintain Traceability Through Surface Treatments

Surface treatments can completely erase codes or make them unreadable by barcode readers. Examples include production processes like coatings and abrasive blasting treatments.

Specialized laser marking processes need to be used to create codes that remain readable through these treatments. Here are two examples:

  • Powder coatings are typically thick, so it’s essential to create deeper codes that can be seen through the coating.
  • Shotblast particles can penetrate the codes and destroy them from the inside, so smaller holes need to be created to prevent particles from getting in.

Here is an example of laser marked identifiers that maintain readability through shot blasting:

Before Shotblasting

After Shotblasting

If you have surface treatments that compromise your traceability efforts, the first step is to talk to a laser expert to discuss your application and perform tests on your parts.

Integrate the Marking Operation in Harsh Environments

Production environments like casting plants, smelting plants, stamping presses, and foundries expose marking systems to high heat, strong vibrations, water vapor, dust, and oil particles in the air. Most marking systems are not made to operate in these conditions.

High-end laser marking systems have IP certifications that attest their ability to function in these conditions.

Meridian, for example, uses our laser marking machines at multiple die-casting plants where air is dusty and temperature varies between 10°C and 50°C. This enables them to meet OEM requirements for traceability and supply them with lightweight die castings.

Minimize the Marking Operation’s Impact on Cycle Time

When traceability is added directly in a production line, one of the concerns is the impact on cycle time. Production can be slowed down by consumable replacement, maintenance, or a slow marking method.

Minimal Maintenance

Previous technologies like CO2 lasers and Nd:YAG lasers required frequent optical realignments, mirror replacements, lamp replacements, or lens replacements. Manufacturer who only had experience with these types of lasers are right to be sceptical of claims that lasers are easy to automate.

But the truth is, advances in fiber laser technology have made the integration of laser technology more automation friendly.

Here are the reasons why high-quality fiber lasers require minimal maintenance in production lines compared to older laser technologies:

  • Their simplified design means that they are not affected by mechanical vibrations and do not need optical realignments.
  • Lenses rarely need replacing, and mirrors never do.
  • Laser sources can operate 24/7 for +10 years with the same marking quality.
  • Higher energy efficiency facilitates thermal management.

Fast Marking Speed

High-quality lasers are fast and can meet the most demanding cycle time requirements.

  • Fiber laser systems have access to almost unlimited laser power. This allows them to be scaled to specific cycle time requirements. At Laserax, we offer up to 1,000W of pulsed laser power.
  • Turnkey laser marking solutions can include additional automation components that maximize the laser’s uptime.

We provide examples of laser marking speeds for aluminum marking, battery marking, and sand marking. If you contact us, we can also perform tests on your parts to provide speeds specific to your application.

Examples of Laser Marking for Traceability

Here are examples of part markings we’ve done for customers or during tests.

A data matrix code is laser marked on the casing of a cylindrical battery cell.

A data matrix code and a serial number on an aluminum die casting.

A rectangular data matrix code was marked on an e-motor rotor to accommodate the part’s shape.

Various identifiers are marked on a battery tray to ensure product traceability.

A laser was used to remove the e-coat from specific areas on a pinion. A data matrix code and text were then marked on the bare metal.

A seating rail was laser marked directly in a stamping production line.

Laser etching was used to create permanent identifiers on a seat bracket.

Serial numbers have been engraved on a sand mold.

VIN markings have been laser engraved 0.5 mm deep to withstand abrasion and prevent counterfeiting.

As raw materials used in the automotive industry, aluminum ingots need to be identified to ensure traceability throughout the entire supply chain.

Test Laser Marking for Your Traceability Application

If you are interested in using laser marking for part traceability, you can send us samples to be marked. We will send you a report that includes:

  • Test results, including marking times at different power levels
  • Videos and photos of the marking operation
  • The minimal laser configuration to meet your requirements
 

Let Us Know Your Application

Olivier Proulx's picture

Olivier Proulx

Olivier is responsible for the development of Laserax’s most widely used laser marking system, the LXQ. He is trained on industrial electronics technologies. He also has extensive experience in automation and is responsible for training new automation staff at Laserax.