Laser Marking Technology for Industrial Product Coding

Over the last few years, the market for laser marking systems has been in a state of perpetual growth. Thanks to numerous technological advances and expanded product options, today’s laser systems are not only faster, more effective, and more precise than ever before, but they are also more accessible to companies of varying sizes and industries. 

Twenty years ago, laser marking systems were significantly more expensive than other marking options like continuous inkjet printers and thermal inkjet printers. Laser’s relatively high cost of ownership prevented most companies from using laser systems, although high-volume operations such as large-scale breweries, bottling facilities, and snack manufacturers that use paperboard were increasingly integrating them into their production lines.

Today’s laser system technologies, which include fiber laser, CO2 laser, and UV laser systems, are more affordable and deliver better results than older models. As a result of these developments, the laser market is projected to continue growing as more industries utilize laser coding technology. Laser’s popular marking applications currently include:

• Aerospace parts
• Food packaging 
• Beverage bottles and cans
• Chemical packaging
• Personal care packaging
• Cannabis packaging
• Wire and cables
• Electrical components
• Pharmaceutical packaging 

Below, we take a look at these different technologies, explain how they work, and examine their possible applications. 

Fiber Laser Marking Systems Explained

Fiber laser systems utilize solid-state laser technology to mark substrates with long-lasting codes and images. 

As opposed to gas lasers or excimer lasers, solid-state lasers use solid materials to amplify light. In a laser system, light-amplifying materials are called “gain mediums,” and the gain medium used by fiber lasers is a length of optical fiber with added rare-earth ions to improve energy release (adding these materials is called “doping”). 

To simplify, here’s how fiber laser systems work:

1. A laser diode, arc lamp, or similar light source injects energy into the optic fiber (these energy-emitting devices are called “pump sources”). 
2. The light excites the rare-earth ions, leading them to emit photons. 
3. The released photons bounce within the fiber, amplifying the light and sending it to an optical cavity. 
4. In the optical cavity, the light is reflected back and forth to both increase intensity and form a concentrated beam. 
5. Once triggered, the beam is released to the substrate to create the intended marking. 

Fiber laser wavelengths vary based on gain medium, fiber design, and other factors. The average wavelength is 1064 nm, though wavelengths can reach up to 1550 nm with certain materials. Wavelength influences substrate compatibility and therefore is a major influence on whether or not a fiber laser can complete certain applications. 

Fiber lasers are generally compatible with metals, rigid plastics, and similar materials, including:

• Steel
• Aluminum
• Brass
• Titanium
• Metallized boards
• Ceramics
• Polypropylene
• Low-density polyethylene (LDPE)
• High-density polyethylene (HDPE)
• Polystyrene
• ABS
• Polyacetal
• Polyamide
• Polycarbonate

With the right preparations, fiber lasers can also mark wood, thermal labels, paper, boards, and glass fiber.

CO2 Laser Marking Systems Explained

CO2 lasers fall into the category of “gas-state lasers,” meaning they use gasses to amplify light. More specifically, CO2 laser systems use tubes filled with a low-pressure mix of carbon dioxide, nitrogen, helium, and other gasses as their gain medium.

CO2 laser systems create light by applying high-voltage electricity to the gas-filled tubes. The electricity stimulates the gas particles, causing them to enter a higher state of energy. The stimulated particles then return to their normal state, releasing photons in the process. 

The released photons bounce between two mirrors set at each end of the tube. As the light bounces, it builds in intensity and forms a beam. Once the beam is ready, the system releases it to the substrate and creates the intended marking. 

CO2 laser systems create beams at a 10.6-, 10.2-, and 9.3-micron wavelength. These beams are capable of marking:

• Wood
• Thermal labels
• Paper
• Board
• Metallized board
• Fruits and vegetables
• Glass
• Glass fiber
• Ceramic 
• Polypropylene
• Low-density polyethylene (LDPE)
• High-density polyethylene (HDPE)
• Polystyrene
• Polyacetal
• Polyethylene terephthalate

With the right preparations, CO2 lasers can also mark polyamide.

UV Laser Marking Systems Explained

UV lasers can use either solid-state or gas-state laser marking technology to code substrates.

Solid-state UV lasers use crystals or glass as their gain mediums. These mediums are doped with UV-active materials (e.g., titanium, chromium, neodymium, etc.) to produce lasers in the ultraviolet region of the electromagnetic spectrum (typically around 200-400 nm). When light is pumped to the gain medium, it excites the ions and releases photons. The photons bounce back and forth between two mirrors on either end of the gain medium until the beam is strong enough to be released through one of the mirrors and onto the substrate. 

Gas-state UV lasers use gas mixtures for their gain mediums. Mixtures typically contain a combination of noble gases and halogen gases. The gasses are contained in a sealed chamber where electrodes emit electrical charges to increase their energy levels and emit photos. As with other systems, the photons are reflected between two mirrors until the beam is strong enough to exit the chamber and mark the substrate. 

UV lasers are capable of marking:

• Glass
• Glass fiber
• Polypropylene
• Low-density polyethylene (LDPE)
• High-density polyethylene (HDPE)
• Polystyrene
• ABS
• Polyacetal
• Polyamide
• Polycarbonate
• Polyethylene terephthalate

With the right preparations, UV lasers can also mark ceramic materials.

InkJet, Inc. is Your Source for Laser Marking Technology

Over the last few years, laser coding systems have become increasingly accessible and cost-effective for many industrial packaging and manufacturing companies. Fast, reliable, and versatile, laser systems are ideal for operations that require high coding speeds and consistently excellent results. 

If you are looking for a laser system for your operation, InkJet, Inc. can help you find the perfect solution for your needs. We carry a variety of systems to meet the requirements of different facilities, industries, and line setups. Contact us today to discuss your laser options. 

For more information about laser marking technology, contact InkJet, Inc. online or call 1(800) 280-3245.