Kerf settings for laser thickness

just wondering is there anyway to change the laser kerf i.e. its diameter

Your question is rather vague, but if you are talking about the physical laser beam itself, the only way I know is to change the focal length of the lens. A 1.5" lens is going to have a fractionally smaller beam spot size compared to a 2".

If you are over-powering the cut more than necessary now (too much power or running slower than necessary), depending on the material, you can often reduce the kerf slightly by running the cut faster and/or lowering the power.

Many thanks for your reply.
Since lasers can have a range of different point sizes i.e. 1mm - 0.3mm etc… on the software side itself trying to input the actual point diameter for the laser being used like the tool diameter input for machining…

LightBurn does support a kerf offset setting for cuts. You enter a distance, either positive (outward) or negative (inward) and it will adjust when generating the cut.


Sure many thanks, it is not the offset we are trying to set, it is the actual dot size of the laser the software is using for its calculations. Like the tool diameter on a cnc router for example… 3mm bit 5mm bit etc…

Also we are using Lightburn on the Marlin configuration for the ramps boards and it is not moving the z steps we have set on the cut settings. Its staying at same z high per pass… would appreciate any ideas why this is ??

The software does not use dot size for any calculations. Typically lasers are treated as “infinitely thin” with two exceptions: creating pockets or fitted parts, where you would use Kerf, or scanning images, where you use the line interval setting to indicate the distance between rastered lines.

For Z, you need to enable the Z control in the Device Settings window, and you’ll also likely want to specify “Relative Z moves only”, as that will run Z relative to your starting height, instead of having to specify an initial height numerically.


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Many thanks for clarifying… :slightly_smiling_face: