How to choose/adjust/replace/maintain the lens of the laser engraving machine?

September 07, 2023

Laser engraving machines have revolutionized the world of precision crafting and industrial manufacturing. These machines utilize a variety of lenses to ensure accurate focusing and efficient engraving. Consequently, it helps in enabling intricate designs and accurate engravings. This comprehensive guide will delve deeper into the intricacies of lens selection, adjustment, replacement, and maintenance for laser engraving machines.

You can also learn about the different types of lenses available for optimal performance.

Laser engraving machine lenses that Startnow offers.

Startnow primarily specializes in distributing CO2 laser engraving machine lenses, encompassing both focusing and reflective lenses. These lenses play pivotal roles in concentrating and redirecting laser light. Moreover, the product range includes field lenses, beam expanders, and beam combiners.

Understand different types of lenses for laser engraving machine

However, here we have brought details of each laser engraving machine’s lens type to make things more understandable. So, here we go:

CO2 Laser Lens

The CO2 focusing lens exhibits a distinctive yellow color and comprises zinc selenide (ZnSe) material. Startnow also offers two variants of focusing lenses, including:

· PVD ZnSe substrate

· CVD ZnSe design.

These lenses have been meticulously engineered to possess a low material absorption rate. It helps them endure high power densities while maintaining robust heat resistance. The lens surface is fortified with a resilient film layer and enhanced by anti-reflection coatings on both sides.

This coating not only resists detachment and wiping. It will also showcase subtle surface irregularities, resulting in a flat-convex appearance.

Key purpose of CO2 focusing lenses

The primary purpose of these CO2-focusing lenses lies in diminishing or eliminating reflected light emanating from optical surfaces such as lenses, prisms, and planar mirrors. By doing so, these lenses effectively bolster the light transmission capacity of these optical components while concurrently reducing or eliminating stray light occurrences within the system.

In the CO2 laser industry, the commonly employed 10.6um wavelength exhibits an impressive transmittance of 99.8%. While, a range of products has been introduced with a shared objective. It is done by strategically optimizing the design through the lenses of diffraction and aberration. It helps minimize the focus spot's diameter while maintaining consistent focal lengths.


These focusing lenses find widespread utility within the CO2 laser processing sector. You can effectively cater these to applications, including:

· Laser cutting

· Engraving

· Marking

· Drilling

· Welding

· Heat treatment, etc.

The plano-convex focusing lens

Plano-convex lenses are versatile in laser engraving machines, offering unique advantages for specific applications. It helps in offering unique advantages for specific applications.

These lenses exhibit a flat surface on one side and a convex surface on the other. At the same time, this design allows for efficient focusing of the laser beam while minimizing aberrations. Plano-convex lenses are commonly fabricated from laser-grade Chemical Vapor Deposition (CVD) zinc selenide.

This material boasts excellent optical properties and thermal stability. In addition, both surfaces of these lenses are coated with anti-reflection coatings to enhance light transmission.

Applications of plano-convex focusing lens

Plano-convex lenses find applications across different industries. For example, industrial manufacturing and medical equipment production. This is mainly due to their ability to handle various laser systems and energy levels.

The CO2 reflector: An important component

Apart from focusing lenses, CO2 engraving machines utilize a CO2 reflector. This reflector aids in redirecting the laser beam toward the focusing lens.

The CO2 reflector plays a pivotal role within the laser light transmission system. It serves as a crucial component responsible for reflecting the CO2 laser beam. The CO2 reflector forms a comprehensive optical pathway within the CO2 laser system. This collaborative design not only enhances the cost-effectiveness of the laser machine. It will also optimize spatial efficiency, minimizing laser energy loss and preserving the highest possible laser work efficiency.

Molybdenum: Exploring Advanced Mirror Coatings

Achieving optimal laser beam reflection and precision is important in laser engraving technology. Specialized mirrors play a crucial role, directing laser beams with utmost accuracy to achieve this. Mirrors coated with materials like molybdenum and silicon metal have gained significant prominence. It is because of their unique properties and applications.

Molybdenum has garnered attention for its remarkable reflective properties and suitability for high-energy laser systems. The fact is truer for multiple good reasons, including:

· High reflectivity across a broad spectrum of wavelengths.

· Better thermal stability and minimized risk of coating damage

· Inherent durability

· Low absorption rate for efficient laser beam reflection

Difference between the coating color of the reflective lens

Different coating colors have significance and meanings in the context of reflective lenses and mirrors. It isn't about the mirror's aesthetics but the impact of the performance of the mirror. Coating colors can vary from silver to gold, each serving a certain purpose. For instance:

Silver Coating

Silver-coated mirrors are known for their broad-spectrum reflectivity. This coating color is common in applications requiring reflection across various wavelengths. However, silver coatings can be sensitive to environmental factors and may tarnish over time.

Gold Coating

While Gold-coated mirrors excel in infrared (IR) applications. This is due to their exceptional reflectivity within the IR spectrum. Gold coatings are highly stable and resistant to tarnishing, making them suitable for long-term use.

Maintaining Correct Operation of Laser Cutting Machine Focusing Lens

Proper maintenance of focusing lenses is critical to sustain consistent engraving quality and prolong the lens's lifespan. So, here are three fundamental maintenance points:

Regular Cleaning

The lens surfaces can accumulate dust, debris, and residue from engraving. Regular cleaning with a recommended lens cleaning solution. In addition, a microfiber cloth is crucial to prevent deterioration of the anti-reflection coating and ensure optimal clarity.

Preventing Physical Damage

The lenses are delicate components that require careful handling. Avoid touching the coated surfaces directly, as even minor scratches can significantly impact engraving quality. In addition, always use gentle, non-abrasive techniques when cleaning.

Alignment and Calibration

Laser engraving machines need periodic alignment and calibration checks to ensure accurate focusing and engraving. Misalignment can lead to uneven or distorted engravings. So, you must follow the manufacturer's guidelines for alignment procedures.

Final Thoughts

Selecting, adjusting, and maintaining the right lens for your laser engraving machine is important. It will help in achieving consistent, high-quality results. This guide certainly has given you enough knowledge about different lens types, their coatings, and adhering to proper maintenance practices. So, you can now easily make informed decisions.

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