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Choosing the Right Wavelength

May, 2020

Industrial laser markers are capable of engraving, discoloration, cutting and more. However, each system has a specialized wavelength best suited for certain materials. Therefore, it's important to match the appropriate system to the desired mark/application.

Common Industrial Laser Markers

UV laser markers have a higher photon energy and absorption rate than IR systems. These perks make UV lasers the optimal choice for high-contrast, damage-free marking applications. Often used for marking plastic.

Fiber laser markers have a high output power due to their amplification source. They are excellent for high-speed processing applications but suffer from a low peak power and low beam quality. Often used for marking metal, plastic and ceramic.

YVO4 lasers have a high peak power due to their amplification process. They excel at detailed applications but can be slower than their fiber counterparts due to a low output power. Often used for marking metal, plastic and ceramic.

CO2 laser markers use a 10.6 µm wavelength, which is absorbed by transparent materials. These systems are often used for applications such as marking films. The development of high-powered models makes it possible to perform functions such as gate cutting of molded parts and PET sheet cutting. Often used for marking paper, plastic, glass, and ceramic.


1 Contrast Marking on Various Plastics

Suitable Models:
MD-U Series UV laser markers

Print Quality:
- Clear contrast is achieved with minimal thermal damage.
- Higher absorption rates allow UV lasers to maintain quality despite material inconsistencies.

Points to Note:
- The MD-U series uses a proprietary sealing method to achieve the same level of protection as a fiber laser marker (IP-64).
- The MD-U Series utilizes a high absorption rate even with gold, silver, copper, and other materials with high reflectance. This minimizes soot and burrs while not damaging the surface, so corrosion resistant marking and processing is possible.

Benefits of 3-Axis Lasers:
- Distortion free printing is achievable on any shape or target with 3-axis control.
- Marking quality remains the same even if the target is at the edge of the marking area.

Marking comparison

In-vehicle plastic part [Material: Natural Polyamide]

Plastic Tube [Material: Silicon]

Marking comparison

Power switch cover [Material: Urea formaldehyde white]

Gas meter casing [Material: Red plastic]

2 Annealed Marking On Stainless Steel

Suitable Models:
MD-U Series UV laser markers
MD-X Series Hybrid laser markers

Print Quality:
- Clear black printing by surface annealing through purposeful laser defocusing.
- Print without causing damage to fine metal components, with less than 1 µm surface variation.

Points to Note:
- By de-focusing the laser, energy density is decreased and black printing can be achieved without damaging the surface of the material.
- In some cases, fine tuning the pulse frequency (Q-switch) of the laser is needed to minimize damage to the surface of the target.

Benefits of 3-Axis Lasers:
- The variable focal distance of each laser allows for uniform printing on complex shapes, even when purposely de-focusing the laser.
- Distortion free printing is achievable on any shape or target with 3-axis control.

Scale printing on a micrometer

Model number printed on a bearing

3 Engraved Marking on Steel

Suitable Models:
MD-F Series Fiber laser markers

Print Quality:
- Engraved printing on the surface without discoloration.
- Deeper marking can be achieved by overlapping characters.

Points to Note:
- In some cases, a deeper mark can be achieved by overlapping marks that print more quickly rather than one mark that slowly engraves the surface.
- Engraving is made easier by setting the Q-switch frequency low, therefore releasing more energy per pulse.

Benefits of 3-Axis Lasers:
- Large-sized nameplates can be printed with uniform depth.
- Distortion free engraving is achievable in a 300 mm x 300 mm area.

Cast (2D code printing)

Nameplate (iron) engraved printing

4 Printing on Paper

Suitable Models:
ML-Z Series CO2 laser markers

Print Quality:
- ML-Z Series create high-visibility printing by precisely removing the preprinted surface (ink layer).
- High-contrast marking allows for highly readable barcodes and other detailed printing.

Points to Note:
- Darker pre-printed surfaces allow for maximized contrast.
- Barcodes generally require more time to print than lettering.

Benefits of 3-Axis Lasers:
- Printing is always consistent and is not affected by carton warpage or expansion.
- Tapering curved surfaces can be accounted for when marking, allowing for undistorted printing on complex shapes.

Printing on a carton

Surface layer removal

Knowing what different wavelengths are (and aren't) capable of will ensure the desired mark can be achieved. Check out Keyence's CO2 laser engravers and Fiber laser marking machines or download the entire laser marking lineup to learn more.