Nukon Fibre Laser Cutting Blog: Understanding the Optics in a Fibre Laser Cutting Machine Head – The Nukon NLCH

Blog by Steve Haddrell

Fibre laser cutting machines have revolutionised precision manufacturing, offering unmatched speed, accuracy, and efficiency.

At the heart of this technology lies a sophisticated optical system housed within the cutting head.

The cutting head is essential to the laser cutting process as it delivers the energy of the laser to the workpiece. The Nukon NLCH is an example of how a high quality cutting head can enhance the performance of a fibre laser cutting machine.

This blog explores how the optics work together to transform high-powered laser light into a finely focused beam capable of slicing through metal with surgical precision.

The Role of Optics in Laser Cutting

The optics in a fibre laser cutting head serve three primary functions:

Beam Delivery: Transmitting the laser from the fibre source to the cutting head.
Beam Shaping: Collimating and focusing the laser to a precise spot.
Protection: Shielding sensitive components from debris and thermal damage.

Key Optical Components and Their Functions

Here’s a breakdown of the main optical elements inside a fibre laser cutting head:

Component	Function
Optical Fibre Core	Transmits the laser beam from the source to the cutting head.
Collimating Lens	Converts the diverging beam into a parallel beam.
Focusing Lens	Focuses the collimated beam to a small spot for cutting.
Protective Windows	Shields internal optics from dust, slag, and cutting gases.
Nozzle	Directs assist gas and laser beam onto the material.
Ceramic Holder	Holds the nozzle and isolates it electrically for sensing.

Optical Path Diagram

Here’s a simplified diagram of the optical path inside a fibre laser cutting head.

Step-by-Step Beam Journey:

Laser Source: The beam is generated in the fibre laser source and travels through the optical fibre.
Collimating Lens: The diverging beam is collimated into parallel rays.
Focusing Lens: These rays are then focused to a precise spot on the material surface.
Protective Windows: Protective lenses prevent contamination and thermal damage.
Nozzle: The focused beam exits through the nozzle, accompanied by assist gas (e.g., oxygen or nitrogen) to aid in material removal.

Auto-Focus and Sensor Integration

Modern cutting heads often include:

Motorized Lens Adjustment: Enables dynamic focusing based on material thickness.
Capacitive Sensors: Detect the distance to the workpiece and adjust the head height in real time.
Monitoring of Temperature, Humidity & Stray Light: Constant monitoring of the conditions prevents overheating, fogging of sensitive optics. It also prevents damage by detecting an issue before it causes serious damage.

These innovations ensure consistent cut quality across varying materials and geometries.

Why Optical Cleanliness Matters

Even microscopic contamination or vapour on lenses can scatter the laser beam, reducing power density and cut quality. Regular maintenance and protective lens replacement are essential to preserve performance.

Conclusion

The optics in the Nukon NLCH fibre laser cutting head are a masterclass in precision engineering.

From beam collimation to real-time focus adjustment, each component plays a vital role in delivering high-speed, high-accuracy cuts.

As laser technology continues to evolve, we can expect even smarter, more adaptive optical systems from Nukon that push the boundaries of industrial fabrication.

Want a chat with Steve Haddrell about your fibre laser cutting plans?

Email sales@nukonlasers.co.uk

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