Know Your Options to Protect Expensive Laser Optics
Kagan Pittman posted on November 20, 2015 |

Original Equipment Manufacturers (OEMs) use laser technology to improve the accuracy of their cutting, welding and drilling techniques. The technique is used across automotive, commercial, medical and military industries.

Though laser precision processes are ubiquitous, there are certain flaws. For instance, the sensitive optic sensors combat environments with red-hot slag, molten metal, dust and other kinds of laser cutting debris. A degraded laser emitter or cutting head reduces efficiency resulting in poor quality cuts and wasted money.  

To combat the harsh environments and protect optical equipment, manufacturers turn to laser optical debris shields. These debris shields, or cover slides, come in a variety of designs and thicknesses to protect the laser from particle spray.

A collection of debris shields. (Image courtesy United Lens Company.)
A collection of debris shields. (Image courtesy United Lens Company.)

Debris shields can prolong the service life of high-power refractive and reflective optics. In this defensive role, debris shields can take on a lot of damage. When a shield has a significant scratch mark, the laser beam can scatter. When this happens, manufacturers are again faced with sloppy cuts and wasted metal.

Depending on the application, debris shields can last anywhere from a single working shift of eight hours to a whole week before developing compromising damage. Therefore, suppliers like United Lens Company (ULC) step in to ensure their customers have a consistent supply.

“Manufacturers wouldn’t want to proceed with cutting and welding without protecting their expensive equipment,” said Tara King, sales manager at ULC. “Our primary function is to make sure that we are able to manufacture these things quickly, efficiently and have them on the shelf for when people need them.”

Finding the Right Debris Shields

Factors like material, surface accuracy, surface quality, parallelism, thickness, diameters and precision tolerances must all be carefully considered when looking for the right debris shields.

Debris shields offered by ULC have diameters ranging from 5mm to 135mm with thickness tolerances between 0.20mm to 0.020mm.

The materials available to design the debris shields include:

  • Schott N-BK7, an optical glass made from Borosilicate Crown glass,
  • Highly pure glass produced fused quartz, made by melting high purity, naturally occurring quartz crystal and
  • Highly pure fused silica glass created from synthetic silicon sand. 

(Image courtesy of United Lens Company.)

(Image courtesy of United Lens Company.)

Anti-Reflective (AR) coatings come in a variety of application-specific varieties including High Efficiency Broad-Band AR coatings (HEAR), double and triple AR and V-Coats. Both sides of the shield are polished simultaneously for increased parallelism.

Debris shields can even be custom made to optimize:

  • Durability
  • Transmitted wave front (TWF) distortion
  • Reflectivity.

However, this array of options doesn’t need to confuse manufacturers. Identifying what debris shields are best for a laser cutting machine is as easy as sending in your old parts and having them analyzed.

“If somebody has an old debris shield, as long as it’s not too terribly damaged, they can send it to us,” King said. “We can reverse engineer it to discover its original size, shape, type of glass, transmission of the material, performance and index of refraction.”

United Lens Company’s Tips for Proper Debris Shield Maintenance

ULC is a supplier for laser cutting OEMs and has been in the optics business since 1916. With this level of experience, ULC has plenty of tips and tricks to ensure the longevity of debris shields:

  • Rotate debris shields to get multiple uses from a single window. Be aware that the effectiveness of this technique is dependent on the laser’s design.
  • Avoid shooting just the center of the work piece. Shooting off center and at the outside can help prolong the effectiveness of the shield.
  • Don’t hesitate to ask your debris shield supplier questions by submitting an RFQ or talking to an expert.

The key takeaway is understanding what it is you’re investing in for your machines.

“If customers need to have a certain performance at a certain wavelength, we would be able to achieve that here,” King said. “The great thing about our facility is that we would be able to custom tailor what our customers need.”

Why endanger expensive tools and risk the quality of your products? To find out more about ULC’s debris shields, visit

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United Lens Company has sponsored this post. They have no editorial input to this post - all opinions are mine. Kagan Pittman

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