Laser Marking of Glass

There are a few different techniques used for laser marking of glass. Whether you require an etched mark on the surface of the glass or an internal glass mark with no effect on the surface, laser glass marking can meet your needs. With its many advantages over traditional glass marking techniques, laser marking of glass is used widely in many industries.

Control Micro Systems, Inc. (CMS Laser) custom laser glass marking systems can bring flexibility, speed, and repeatability to your glass marking applications.

Advantages of Laser Marking of Glass:

• No consumables – Laser glass marking does not require extra consumables like other glass marking methods such as sand blasting or ink printing.
• Able to mark internally without affecting outside surface – See Internal Glass marking method below for more details.
• Repeatability – Marking is extremely accurate and repeatable from part to part due to the laser’s localized energy and the system’s accurate controls.
• Flexibility – Intricate graphics, text, and more can be etched. Also, switching between marking different types of parts is very simple with CMS Laser’s custom software capabilities.
• No need for stencils or masks – CMS Laser markings systems steer the laser through the marking path (like a pencil on paper) instead of requiring specific masks be made for each design. Marking a new design is as simple as uploading a new drawing file.
• Easy Automation – Laser glass marking can easily be integrated into an automated system. CMS Laser can also mark glass On-The-Fly.

Methods of Laser Marking of Glass:

The two basic methods of marking glass with lasers are External Marking and Internal Marking.

External Glass Marking External glass marking etches the surface of the glass to cause the reflections of light off the surface to change which creates a contrasting mark to the eye.

External glass marking uses the following wavelengths of laser.

10.6um (CO2 Laser):

• Marks the surface with dots that show concentric cracking but have minimal to no radial (or dot to dot) cracking allowing the mark to have a consistent appearance and minimizes extra chipping.
• CO2 Laser glass marking is the fastest option for marking glass and is used in many applications that require automation or on-the-fly marking.

355nm and 532nm (Nd:YVO₄ Lasers):

• Marks the surface of the glass with thin lines of micro fractures on the glass that create a frosted look.
• 355nm and 532nm marking allows for very intricate graphics and designs to be marked but is an inherently slower process than CO2 marking.

Applications for external glass marking span many different industries. A few of the most popular include:

Decorative Glass Marking

Nucleation

Marking on Rounded Surfaces

The depth of focus of the laser allows for marking over small variations in the surface of the glass. This allows for marks to be placed on gently rounded surfaces including (but not limited to) wine bottles, stemware, and other drinking glasses.

Automotive Anti-Theft Glass Marking

CMS Laser manufactures a portable, handheld, laser glass marking machine for etching VIN numbers onto automotive windows for anti-theft protection. US PATENT#: 8598489. Below is a picture and video showing this machine in use!

Internal Glass Marking

Internal glass marking precisely focuses the laser energy into the interior of the glass and creates micro fractures and a visually contrasting mark inside the glass. This type of glass marking has no effect on the outside surface.

Internal glass marking uses 355nm (Nd:YVO4) or Ultrashort Lasers.

These lasers can be focused to spot sizes which allow for high energy density and absorption at precision locations within the glass.

3D graphics can be marked internally in the glass by changing the z-height while scanning in X and Y. (see pictures below).

Decorative glass marking is the most popular application for internal glass marking.

Backlit Graphic Marking

Another application for laser glass marking is to remove an opaque coating substance (paint for example) from a glass surface to then allow for backlighting of the laser removed areas.

Many different wavelengths of laser, ranging from IR to UV, can be used for this application depending on the type of coating that is being removed. Wavelengths that are absorbed by the coating but transmitted by the glass would be the ideal solution. The Applications Lab at CMS Laser will determine the best wavelength for your project.

Graphics, text characters, or even data matrixes can be removed from the coating without damaging the glass.