How to Choose/Adjust/Replace/Maintain CO2 Laser Engraving Machine Lenses?
Startnow primarily sells CO2 laser machine lenses, which can be categorized into focusing lenses and reflecting lenses. These lenses are used for focusing and reflecting laser beams. Additionally, there are field lenses, beam expander lenses, and beam combiner lenses.
CO2 Focusing Lenses: These lenses are typically yellow in color and made of Zinc Selenide (ZnSe). Startnow offers both PVD ZnSe and CVD ZnSe focusing lenses.
They have low absorption rates, can withstand high power densities, exhibit strong heat resistance, and feature durable double-sided anti-reflective coatings that are resistant to scratching. The lens surfaces may have slight irregularities, but they provide effective focus for laser beams.
Double-sided Anti-reflective Coating: This coating reduces or eliminates reflections on optical surfaces like lenses, prisms, and flat mirrors, increasing their transmittance and minimizing stray light in optical systems.
In the commonly used working wavelength of 10.6μm for CO2 lasers, the transmittance can reach up to 99.8%. These lenses are optimized for minimal spot size under the same focal length conditions, producing high-density focal points for various laser processing applications such as cutting, engraving, marking, drilling, welding, and heat treatment.
Common diameters: Ф12/15/18/19.05/20/22/25.4/28/38.1mm
Focal length: F38.1/50.8/63.5/76.2/90.25/101.6/127
Convex-Convex (Meniscus) Focusing Lenses: These lenses have one flat and one convex surface, made from laser-grade PVD ZnSe material with double-sided anti-reflective coatings. Meniscus lenses effectively reduce spherical aberration, producing smaller beam spots compared to flat-convex lenses.
From substrate to manufacturing to coating, we maintain strict quality control to ensure the highest quality lenses for our customers. Meniscus focusing lenses should have their convex side facing the incident beam and the concave side towards the workpiece. These lenses find applications in industrial and medical laser systems for cutting, welding, hardening, and more.
CO2 Reflecting Lenses: These are essential components in the laser optical path, responsible for reflecting CO2 laser beams. In the CO2 laser path, reflecting lenses and focusing lenses work together to create an efficient optical path, optimizing space utilization and minimizing laser losses to maximize laser efficiency.
Molybdenum and Silicon Reflecting Mirrors Reflecting mirrors are typically made from molybdenum or silicon as the substrate material. Molybdenum mirrors are known for their durability in harsh environments, long lifespan, high power handling, and they do not require additional coatings. However, their reflectivity is slightly lower compared to silicon mirrors.
Distinguishing Reflecting Mirror Coating Colors: The surface color of reflecting mirrors varies based on the substrate material and coating. Molybdenum mirrors retain their natural metallic color, while silicon mirrors can have coatings made from materials like gold, silver, aluminum, or non-metallic dielectric coatings. Gold appears yellow, silver is silver-colored, and dielectric coatings also appear silver. Common diameters include Ф19/20/25/27/30/38.1/50/50.8mm.
How to maintain the correct operation process of focusing lens of laser cutting machine:
  • Removing the lens: Loosen the securing screws, remove the nozzle and lens barrel, and use a rubber bulb blower to remove dust from the lens surface.
  • If cleaning is necessary, use laboratory-grade soft cotton swabs dipped in a small amount of acetone or high-purity alcohol. Gently rotate the swab in a clockwise direction from the center to the edge of the lens. Clean both sides if required. Handle the lens with care to avoid contamination.
  • Reassemble the lens barrel and nozzle, adjust the focal distance, tighten the securing screws, and ensure that the convex side of the focusing lens faces downward.
Maintenance Tips for CO2 Laser Focusing Lenses:
  1. Handle the focusing lenses with care as they are fragile and can be damaged easily. Avoid applying excessive force or causing any impact.
  2. Protect the lenses from contamination, moisture, and oily substances. Provide dry and oil-free air during operation. Do not touch the lens directly with your hands, as skin oils can cause permanent damage. Always use gloves or specialized tools for handling.
  3. Regularly inspect the lenses before and after cleaning. Use magnification equipment to check for contamination and defects. Illuminate the optical surface with a bright light source to enhance the visibility of contaminants and defects.
  4. When cleaning, use clean wiping paper and optical-grade solvents to prevent further contamination. Wipe gently and avoid drying out the swab. If a lens continues to show reduced cleanliness after multiple cleanings, consider replacement to maintain processing efficiency.
 ☆Important Reminder: 
Beginners should follow the instructions and consult technical experts when performing these operations. Additionally, exercise caution when working with lasers, as they can cause burns and are invisible, requiring proper safety measures when adjusting optical paths.
Co2 laser engraving machine parts

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