CO₂ laser wavelength selection

9.3, 10.2 or 10.6 µm: which CO₂ laser wavelength?

Wavelength changes how energy is absorbed by a material. Choosing it from the substrate and required mark can matter as much as choosing laser power.

Short answer: 10.6 µm is widely used for paper, board, glass, wood and many organic materials; 10.2 µm is often evaluated for flexible packaging films such as OPP, PP and PE; 9.3 µm is commonly assessed for PET. These are starting points—formulation and line speed still require sample testing.

Quick wavelength guide

Wavelength	Often assessed for	What to confirm
9.3 µm	PET bottles and selected PET films	Contrast, foaming, distortion and wall thickness
10.2 µm	OPP, PP, PE and flexible films	Film integrity, code contrast and web speed
10.6 µm	Paperboard, labels, coatings, glass, wood and organics	Coating response, etch quality and marking time

Why material names are not enough

Two products both labelled PET or polypropylene can mark differently because pigments, fillers, layers, coatings and recycled content change absorption and thermal response. Even a small packaging specification change can affect code appearance.

That is why we request current production samples rather than selecting from a generic material list.

Wavelength is one part of the optical system

Source power, pulse behaviour, lens, spot size, focal distance, marking field and scan strategy all influence the result. A smaller field may improve energy density but reduce tolerance to product position. High line speed reduces available marking time.

A practical selection process

Start with the required code grade and permanence. Test candidate wavelength and settings on representative samples, including colour variants. Then confirm performance at the expected product speed and focus variation before finalising the machine specification.

Frequently asked questions

Direct answers for buyers.

Recommendations are confirmed against the real material and production line.

What is the standard CO₂ laser wavelength?+

10.6 µm is the common general-purpose CO₂ wavelength, but 9.3 and 10.2 µm sources can perform better on specific packaging polymers.

Which CO₂ wavelength is used for PET bottles?+

9.3 µm is commonly evaluated for PET because it can create a clear frosted mark, but the bottle formulation, colour, wall thickness and speed must be tested.

Can I select wavelength from a technical data sheet?+

A data sheet helps narrow the options, but it cannot fully predict contrast, damage or speed on the finished product. A representative marking trial is the reliable next step.