Marking Knowledge

Marking FAQ

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Marking FAQ Answers Part 1

Q1 What is the difference between YAG laser markers and CO2 laser markers?
A1 The wavelengths of the laser beams are different. The wavelength of a YAG laser is 1.064 µm, and that of a CO2 laser is 10.6 µm.

Differences between YAG and CO2 lasers
The wavelength of a YAG laser is one-tenth that of a CO2 laser. This allows lower reflection of the laser beam on a metal surface, reduced loss of energy, and easier working of metals. Conversely, a CO2 laser is in the range of the wavelengths in which energy is easily absorbed into glass and other transparent objects, making it suitable for marking clear targets. Note that the ability to change the color of plastics varies depending on the material because of the difference in the laser-beam absorptivity (Refer to the table in A3 as a guide). In general, a YAG laser can change the color of more varieties of plastic than a CO2 laser.

Wavelengths of lasers used for marking
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Q2 How do I know which marking device to use for specific materials?
A2 The following table shows marking devices and their applicable materials.

Material YAG laser marker
MD-Y Series
(Reference: KEYENCE product)
CO2 laser marker
ML-G Series
(Reference: KEYENCE product)
Plastic Good Good
Metal Good Good (Stainless steel only)
Plating Good Unacceptable
Transparent object (glass, plastic) Unacceptable Good
Ceramic Good Good
* Good and Unacceptable in the table may vary depending on the target condition, use of additives, and marker settings.

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Q3 What are the materials that change or do not change colors with YAG laser markers and CO2 laser markers, respectively?
A3 The following table shows typical materials that change colors with the respective markers.

Material YAG laser marker
MD-Y Series
(Reference: KEYENCE product)
CO2 laser marker
ML-G Series
(Reference: KEYENCE product)
Plastic PE (Polyethylene) Very Good Good
PC (Polycarbonate) Very Good Good
PP (Polypropylene) Very Good Good
POM (Polyacetal) Very Good Good
PBT (Polybutylene terephthalate) Very Good Good
PET (Polyethylene terephthalate) Acceptable Good
ABS (Acrylonitrile butadiene
styrene)
Very Good Good
EP (Epoxy) Very Good Very Good
PF (Phenol) Very Good Very Good
UF (Urea) Very Good Very Good
PVC (Polyvinyl chloride) Good Very Good
PA (Polyamide/Nylon) Very Good Good
Metal Iron Very Good Unacceptable
Aluminum Very Good Unacceptable
Stainless steel Very Good Good
Plating Very Good Unacceptable
Alumite treatment Very Good Good
Ceramic Good Good
Other Glass Unacceptable Good
Rubber Good Good
* Very Good, Good, Acceptable and Unacceptable in the table may vary depending on the target condition, use of additives, and marker settings.
Very Good: Very good for this material.
Good: Good for this material.
Acceptable: Acceptable for this material.

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Q4 How are lasers classified?
A4 "Laser Product Emission Safety Standards" (specified in JIS C6802) classifies all types of lasers into 5 levels based on their influence upon a human body.

Safety class standards
Class 1 Inherently safe No special safety measures required (e.g. laser printer, CD).
Class 2 Safe Class specified for visible light (e.g. laser pointer).
Class 3A Potentially hazardous Viewing the beam with optical instruments is hazardous (a system that emits a visible laser).
Class 3B Rather dangerous Directly viewing the beam is hazardous. (It is safe to view the diffuse reflection from a distance of 13 cm or more for 10 seconds or less.)
Class 4 Extremely dangerous Even the diffuse reflection may be hazardous, causing skin injuries or burns, or fire. (Many experimental or industrial lasers are in this class.)
Note: Laser manufacturers must attach warning labels on products classified as Class 2 or higher.

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Q5 What safety measures are required to install a laser marker?
A5 A typical installation example is shown in the figure below.

Safe installation guidelines
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