The Correct Lens for Perfect Results

Choosing the Right Lens

The parameters are fine and the focus is set correctly, but somehow the engraving is still not correct. Has this ever happened to you?  You're most likely experiencing a lens issue. The correct lens is just as important as the right parameters and optimal focus adjustment.

To select the correct lens, you must consider the following factors:

• Output of your laser device

• Material

• Detail level of the graphics

• Resolution (dpi)

• Thickness of the material

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The Rule of Thumb:

The more delicate and detailed the graphics are, the smaller the lens should be. For cutting thick materials,  larger lenses are recommended. 

Technical features in plain terms:

The following is a glossary of the terms used to discuss lenses.

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Focal length

Distance between the lens and the point of the smallest beam diameter (= focus).

Focus

The area where the laser beam is optimally focused and converges to the smallest possible beam diameter.

Beam diameter

The diameter of the laser beam which becomes wider before and after the area of focus. The longer the focal distance of the lens, the greater the beam diameter. The energy of the laser is focused by the lens onto a defined focal point. The greater the focal distance of the lens, the greater  the surface onto which the energy of the laser is applied. This may mean that if you use a large lens, the material is heated rather than cut.

Focus tolerance (depth of focus)

The area in which the beam has the smallest diameter.The larger the lens (= the larger the focal length of the lens), the longer the focal tolerance. This means that the focus tolerance of a 5” lens will be twice that of a 2.5” lens. This is especially important if you want to cut through thick materials.

Check out this chart on troteclaser.com to see our Speedy and SP series lens portfolio.