What Type of Laser Marking Applies to You?

Let's Get Down to the Nitty Gritty

When we interact with our customers or prospective clients, we often find most of them are not up to par with the intricate knowledge of fiber laser marking. While we understand they’re mostly concerned about their printing problems, at OMTech, we believe they deserve more. So we’re setting out to clarify and educate all our readers on the nitty-gritty of laser marking. In succeeding paragraphs, you will gain ample knowledge about the types of laser marking, their features, and their area of application.

Overview of Laser Marking

Over the years, the advancement of technology has improved marking, engraving, and etching. Laser marking happens to be one of the three well-known methods of permanent marking. The other two ways are laser engraving and etching. However, there are numerous approaches to marking that yield excellent results.

First, you need to understand the term "laser marking." It exposes a material's surface to a low-powered beam without altering the surface's properties or appearance. It makes use of a method known as discoloration to achieve the required high-contrast marking. Sometimes it is referred to as laser coloration.
Second, you should understand that marking is unique and less common compared to engraving and etching. Ultimately, for regular printings such as serial & part numbers and machine-readable printings such as barcodes, ID codes, and QR codes, marking is the way to go.

Types of Laser Marking Systems

Different industries make different uses of fiber marking. Before purchasing a marking system, you should know the various types of machines and how they apply to your industry. Here are the four most common types of marking systems.

Annealing Laser Marking

Annealing refers to marking materials with oxidation using a laser to apply localized heat to the material's surface. From experience, the colors it gives off range from red, yellow, green to black, depending on the surface temperature. With laser annealing, you can expect a solid mark alongside a smooth finish. However, this process requires patience because carbon gradually rises to the metal surface before marking occurs.
Annealing is the best approach to mark metals that contain carbon. It works perfectly on metals such as steel, iron, titanium, and even stainless steel. In fact, stainless steel has been found to corrode if laser engraved and not annealed. That’s one reason why this method of marking is synonymous with the medical industry — it requires stainless steel to remain rust-free for sanitary reasons.  Other sectors where laser annealing is found useful are:

• Automotive industries
• Food industries
• Energy industries

Carbon Migration Laser Marking

This laser marking method involves the heating of metal or its alloys until a chemical bond forms between the metal and carbon molecules. Consequently, the metal's carbon properties reveal themselves on the metal surface, leaving only a dark laser marking. Unlike annealing, this type of marking happens faster, with a high amount of heat applied.
Aerospace, jewelry engraving, and metalworking industries have found this approach very suitable. Appropriate carbon migration materials include steel, stainless steel, carbide and titanium, and all metals containing carbon. On a final note, marking by carbon migration is also an excellent choice for wood, leather, paper, and packaging products.

Foaming Laser Marking

This method is strictly for plastics only. This method works best when the plastic is darker, and the expected marking should be lighter in color. Here, a controlled molten burn is created on the plastic's outer to achieve a brighter color. The "foaming" comes from the act where the surface bears foam and gas bubbles as it melts. The desired print is embedded during the foaming process and remains permanent after cooling. Also, this foam alters the plastic's refraction properties and makes the area lighter.
Any industry that uses plastic will find it very useful. Here are a few products that use foaming laser marking:

• Ink cartridges
• Keyboard
• Airpod cases
• Cosmetic packaging
• Other plastic and tech-related products

Coloration Laser Marking

Coloration marking is the most versatile method of fiber marking. Used for both plastics and metal marking, it can produce a range of colors and black & white contrasts. However, just like the annealing process, it also uses oxidation, and the coloration depends on the material.
This process adds color via heating of specific parts of a plastic or metal with control of frequency, width, and other factors. You can use various modifications to get the desired color shade. In plastics, colors have varying wavelengths; thus, the laser beam manipulates these plastic polymers to change their wavelength. For metals, coloration occurs via oxidation and gives you more freedom to switch colors as you desire.
You can count on coloration marking for decorative applications, animal ear tags, and bottle cap printing. Metals and plastics in this category include:

• Stainless steel
• Titanium
• Chrome
• Glass-filled plastics
• ABS plastics
• Polyethylene plastics

Final Thoughts

With such a range of laser marking machines available and several marking methods to choose from, deciding which will best suit your needs requires careful consideration. Feel free to reach out to OMTech for further consultation and guidance — we will walk you through our entire line of fiber marking equipment. We provide customized fiber laser machines tailored to meet your needs and achieve maximum satisfaction.
We look forward to hearing from you!