Laser Marking Facts and Insights
Though the laser marking process is fast and reliable, producing precise and repeatable marks that seem easy to do, there are actually complicated components and systems in place, belying the end results.
Let’s take a look at some facts and insights about lasers and laser marking, including types of marks, types of lasers, safety classifications, applications, and more.
Laser marking wouldn’t be possible without the creation and development of the laser in the 1950s and ‘60s. Here are some key facts to know:
- The laser’s predecessor was the “maser,” named for microwave amplification by stimulated emission of radiation. It was created by Charles Townes and Arthur Schawlow in 1954, and both men later went on to propose the technology that led to lasers.
- In 1958 and 1960 respectfully, Gordon Gould and Theodore Maiman began work independently on laser development projects. Gould was unable to secure a patent in time (though was later credited), making Maiman’s ruby laser the first viable, operational optical laser.
- Lasers for manufacturing purposes weren’t introduced until 1965, when Western Electric began utilizing a laser to drill holes in diamond dies. Later, in 1967, CO2 lasers began to be used for cutting, with refinements made into the mid-1970s.
- During this time, lasers also began to be employed for bar code scanning, transforming the retail sector, among many others. By the mid-1980s, lasers for bar code scanning were found in a third of all grocery stores, and by the close of the twentieth century, such lasers were found in virtually all stores.
- Also during the 1970s, Bill Lawson of LMI and others began to develop the first laser engraving systems. Such systems were later improved upon when Electrox developed and manufactured a commercial fast axial flow CO2 laser.
- In the 1980s and 1990s, laser marking systems began being integrated more heavily with computerized systems, eventually resulting in the modern laser systems companies utilize today.
Types of Lasers for Laser Marking
- MOPA fiber lasers – Utilizing fiber optics, these lasers boast nearly zero energy loss and produce high pulse repetition, delivering precise and contrasting marks. Due to their wavelength, MOPA fiber lasers are suited for use on more durable materials, such as steel, titanium, aluminum, brass, copper, other metals, and plastics.
- CO2 lasers – Using a glass tube filled with various gases that are activated with electricity, CO2 lasers are an older form of laser technology that utilize a higher wavelength. Due to this difference, CO2 lasers are better suited for more delicate materials such as wood, paper, stone, glass, leather, plastics, rubber, and more.
- UV lasers – Operating by way of non-linear crystals, this form of laser features a very short wavelength that is very absorptive. Due to this, “cold marking” is possible, preventing heat stress from damaging items such as silver, gold, and copper. Other material applications include marking silicon, polyethylene, glass, and more.
Types of Laser Marking
Though “laser marking and “laser engraving” are often used interchangeably in an informal way, when examining functionality there are some key differences between the two. Several other marking tactics are possible as well.
- Laser marking – This process features a laser that heats a material, creating oxidation that alters the material’s surface with a high-contrast mark. The surface itself is left intact.
- Laser engraving – In this process, a portion of the material being engraved is physically removed by the laser, creating a cavity. The material removed is vaporized during the process. Deep marks are attainable with this method.
- Laser etching – Considered a subset of laser engraving, this process uses high heat to melt the material’s surface, resulting in a raised mark.
- Laser annealing – In this subset of laser marking, heat is applied just below the melting point of a material to create high-contrast marks, usually jet black in appearance. The medical field and applications using stainless steel commonly utilize this methodology.
- Laser foaming – Using controlled micro burns, this method commonly used for plastic and rubber produces tiny gas bubbles under a material’s surface without vaporization, ending in a slightly raised surface.
- Laser frosting – By using a high rate of scan speed, minimal surface disruption is created on a material, resulting in a bright white contrasting mark.
- Laser ablation – Also known as laser texturing, this approach removes coatings or top layers from materials, producing a bright or white mark that contrasts with the surface or coating.
Laser Marking Classifications
- Class 1 – These laser systems are classified as the safest, utilizing either a low-powered laser or featuring housing that protects operators completely from higher-powered lasers.
- Class 1M – These systems are also incredibly safe, though cannot be used with magnifying optics such as microscopes and telescopes.
- Class 2 – These lasers are deemed safe due to the human blink reflex, as minor exposure to them will do no damage (though intentional, prolonged exposure can). Laser pointers are a common example of Class 2 lasers, and lasers of this type are not utilized for laser marking.
- Class 2M – Much like Class 1M, these lasers cannot be used with magnifying optics like microscopes and telescopes.
- Class 3R – Formally called Class 3A, lasers of this type are low powered and considered safe when used with restrictive beam viewing.
- Class 3B – These medium-powered lasers are dangerous to the human eye with direct exposure, necessitating the use of safety goggles when working with them.
- Class 4 – The highest-powered lasers in the classification system, Class 4 lasers require precise safety protocols for operation, as they are capable of doing damage to the eyes and can also burn skin.
Interesting Laser Marking and Engraving Applications
Laser marking and engraving have been put to use by diverse industries to fulfill thousands of applications. There are some really intriguing examples out there, so here are a few novel ones:
- Students at Purdue University used laser engraving to engrave logos and commemoration information on 100-year-old train tracks, getting to work hands on with equipment while honoring a part of West Lafayette history.
- Scientists and companies have been experimenting with CO2 lasers in the food processing field, as discussed in this article by New Food Magazine, arriving at some promising applications. One use, laser marking directly onto foods, can allow for safe, repeatable, and environmentally friendly labeling, placing bar codes, logos, branding information, and warnings directly and safely onto fruits, vegetables, eggs, meats, and more.
- Possibly most fascinating of all, NASA has now used laser engraving on the surface of Mars, marking rock core samples for tracking and scientific study. Amazing!
Thinking About Investing in a Laser Marking System? Reach Out to Our Team!
If your company is looking for a more effective way to mark parts, or if you’re wanting to update an existing system, be sure to get in touch with us. Our team can assess your needs and determine the ideal options for you.
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