CO2 Laser Marking

CO₂ laser engravers get their name because they use CO₂ gas as their laser medium. It works by generating plasma from CO₂ gas inside of a tube, amplifying that light between a reflective mirror and output coupler, and then output as a laser beam. The output laser beam has a wavelength of 10600 nm and due to this long wavelength they are extremely heat dependent. They are great for material removal and for marking organic materials like cardboard, plastic, glass, and wood.

What is a CO2 Laser?

CO2 lasers use CO2 gas as their medium. CO2 gas is enclosed in a tube with electrodes used for electrical discharge. An electrical discharge generates plasma within the gas, and the generated light is amplified as it travels back and forth between the total reflective mirror and the output coupler. This light is eventually output as the laser.

CO2 laser markers feature a wavelength that's 10x longer than that of conventional fibre systems. They're great at marking plastics, paper, resins, wood, rubber, and transparent materials (like glass and PET).

CO2 Laser Feature: Commonly Used in Cutting Applications

CO2 laser markers rely on heat to mark parts, making them perfect for cutting applications. In fact, CO2 lasers are commonly used for cutting holds, gate cutting, and sticker half-cutting applications.
Compared to mechanical cutting tools, CO2 laser markers are fully automatable, flexible, and almost entirely maintenance free.

Film processing

Wire sheathing cutting

Gate cutting

CO2 Laser Feature: Synthetic Rubber Marking

Synthetic rubber has high heat and chemical resistance properties, meaning some marking methods are not strong enough to mark it. However, CO2 laser marking has very high heat absorption, allowing it to etch marks onto synthetic rubber.

CO2 laser marking synthetic rubber applications:

  • Wiper blades
  • Rubber gloves
  • Car tyres
  • Belts

Rubber gasket - Head lamp

Wiper blade

Door moulding

CO2 Laser Feature: Marking on Glass

Glass has high heat resistance and is commonly transparent. Standard Fibre wavelength systems are unable interact with glass due to these properties; however, incorporating a CO2 laser makes the marking process seamless. CO2 lasers engrave white marks into glass by gently generating tiny cracks, micro-fractures, using low power. The micro-fractures make up the mark or design.

CO2 laser marking glass applications:

  • Windowpane
  • Bottle
  • Jar
  • Drinkware

CO2 Laser Feature: Marking on Cardboard and Wood

Using a CO2 laser for cardboard and wood marking ensures permanent marks that never smudge. The CO2 laser burns designs, logos, barcodes, or characters onto the wood or cardboard surface. CO2 laser marking is used for either white marking or dark marking.

CO2 laser marking cardboard and wood applications:

  • Drink carton
  • Decorative wood sign
  • Shipping box


Design marking

Wood label replacement

Product Introduction

World's first 3-axis control 3-Axis CO2 Laser Marker ML-Z Series

KEYENCE's unique 3-axis control incorporated into the ML-Z CO2 laser marking machine ensures distortion-less marking over the entirety of its field of view. It allows the focal distance to be adjusted over a 42 mm range. This enables precise marking on 3D part shapes and reduces tooling costs. The ML-Z CO2 laser uses the 3-axis control to mark uniformly across step, inclined, cylinder, and circular cone targets and can even use CAD data of non-standard shapes to map its focal path and retain focus.

300 mm wide area

The wide-area models in the ML-Z Series CO2 laser have a marking area of 300 x 300 mm, which greatly simplifies installation costs and reduces processing time.

Variable Beam Spot and Defocusing

The ML-Z CO2 laser marking machine uses focal point and beam spot adjustment to mark various character types. The variation allows marking thin, thick, shallow, or deep characters in the same motion and allows for variability of power density to achieve perfect marks over a wide range of materials.

Conventional Laser Marker

With conventional models, marking is limited to a fixed area.

3-Axis Control ML-Z Series

With the ML-Z Series, high quality marking is possible over a wider area using 3-Axis control.

Improving Quality with Short-Wavelength and Thin Laser Types

9.3 μm vs. 10.6 μm wavelength

ML-Z Series laser markers feature two distinct wavelengths: 9.3 μm and 10.6 μm. The slightly shortened wavelength has a higher absorptivity in transparent materials like resin and glass. As a result, the shorter wavelength model allows for precision marking, shallower engraving, and less surface swelling.

Thin laser type

ML-Z Series laser markers also feature different spot sizes. Smaller spot diameters enable fine-print marking and greater power density, which in turn allows for more efficient processing like cutting and drilling.

9.3 μm Short Wavelength Model


10.6 μm laser

Deep engraving with extensive damage.


9.3 μm laser

Sharp, shallow engraving with minimal damage.

Relationship between wavelength and transmission ratio (PET)

The wavelength of the ML-Z Series’ laser is available at 10.6 μm as well as a shortened 9.3 μm to better suit the heat absorption characteristics of various resins. With a higher absorption rate in resin, this shorter wavelength allows for more precise marking with shallower engraving and less surface swelling.

Thin Beam Model

Compared with standard models, the laser spot diameter is smaller, enabling even finer marking. The smaller spot diameter allows for greater power density, which in turn allows for more efficient processing such as cutting and drilling.

Comparison of Laser Spot Diameter and Power Density

Standard mode Thin beam mode
Spot diameter
Standard mode
140 μm
Thin beam mode
80 μm
Power density
Standard mode
2.0 kW/mm2
Thin beam mode
6.0 kW/mm2

* These are representative values

Standard model

Thin beam model

Thin laser beam models provide greater power density with a narrower spot diameter.

Introducing CO2 Laser Marking to Your Manufacturing Process

Do you process ceramics, glass, rubber, or cardboard? Are you looking for an efficient and precise marking process that standard fibre lasers struggle with? Test KEYENCE's CO2 laser marking machine for your cutting and marking needs.

Our expert team offers you a free demo, trial equipment, and after-sales support if you buy. Contact KEYENCE today to start processing with the ML-Z CO2 laser marker.