As we know, the laser beam is a focused beam of light, and it tends to diverge when moved away from the focal point, resulting in a wider beam and lower energy density. When using laser engraving, we typically focus the laser on the surface of the material to achieve the smallest possible spot size for fine engraving.

 

However, when it comes to cutting thicker materials (≥ 3mm thickness in general), things get a bit tricky. As the laser beam reaches the lower surface of the material, there's often a significant height difference between the top and bottom surfaces. This may increase the laser spot size and reduce its energy density, making it challenging to cut through the material.

 

When you find the material hard to cut after you test several parameters, this is where the Focus Sinking feature comes into play. By adjusting the focus to a point between the top and bottom surfaces of the material, you can achieve a better balance of the laser beam's power density. This, in turn, enhances the laser's cutting capabilities.

 

the optimal sinking distance it's not a one-size-fits-all solution. Several factors come into play, including the material's thickness, its properties, the laser head's power, the focal length of the lens, and the size of the focused spot.

While we can't offer a universal formula, based on our laboratory test, sinking the focus by 3mm can significantly improve cutting performance in most scenarios.

 

In XCS, the sinking distance can be adjusted from 0mm to 6 mm. You may need to perform specific experiments to determine the ideal setting that caters to your needs.

Please be aware that the sinking distance should not exceed the thickness of the material, otherwise your laser head would clash with the material and might cause damage.

 

Kindly take note that the focus sinking function is intended to enhance the efficiency of material cutting and is not a solution for material cutting failure. If your machine encounters difficulty cutting through materials, you can first test your parameters using the Material Test Array function in XCS software.