Laser Cutter Settings

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This page describes the settings we have used for our laser cutter on the specified materials. These values are bundled into the Knox Makers LaserCNC Inkscape plugin. See here for latest release of the plugin.

Link back to Laser Cutter home.

Table of Values by Material

After testing some sample materials, these values were selected based on giving the best visual impression. That includes minimal charring and smoking, best accuracy, and are ultimately entirely subjective. Use these as starting points for your experiments. See below for an explanation of what the parameters mean.

Material Action Feed Rate Laser Power
3mm Plywood Cut F800 Q0.4
3mm Plywood Engrave Heavy F1500 Q0.18
3mm Plywood Engrave Light F1500 Q0.14
6mm Plywood Cut F400 Q0.6
6mm Plywood Engrave Heavy F1500 Q0.18
6mm Plywood Engrave Light F1500 Q0.14
3mm Acrylic Cut F400 Q0.4
3mm Acrylic Engrave Heavy F400 Q0.152
3mm Acrylic Engrave Light F1000 Q0.164
6mm Acrylic Cut F200 Q0.6
6mm Acrylic Engrave Heavy F1000 Q0.2
6mm Acrylic Engrave Light F1500 Q0.12
Paper Cut F500 Q0.165
Paper Engrave Heavy F1500 Q0.128
Paper Engrave Light (Perforate) F1000 Q0.2
Cardboard Cut F1000 Q0.5
Cardboard Engrave Heavy F1000 Q0.14
Cardboard Engrave Light F400 Q0.13

Note: These are the values used by default in the version 0.** (update pending) of the Inkscape Plugin. All values use S10000, except for Paper, Engrave Light. It uses S1 to perforate instead of mark.

Table of Values for Alternate Materials

These are values that we have discovered in our tinkering to be used as helpful guides for others. These are less common or less regular materials and are not currently included in our Inkscape Extension.

Material Action Feed Rate Laser Power Notes
Leather Engrave F1000 Q0.128 Marks cleanly without heavily charring.

GCode

The laser cutter operates using LinuxCNC, and uses 3 specific commands to modify the type of cut made by the laser.

M68 Command - Q Parameter

The M68 command is used by LinuxCNC to specify an analog output. Our laser is configured to use the E0 output and the Q parameter to modulate the laser power when cutting in automatic mode. Based on previous testing a Q value less than 0.12 are insufficient to even brown paper at most speeds. Values greater than 0.6 will cause the laser to exceed its maximum current. For than reason, this parameter is internally limited to 0.6. Putting in larger values will not have any effect.

Samples:

  • M68 E0 Q0.125 - This would represent a very low power beam. Speeds would have to be very low to mark anything other than paper.
  • M68 E0 Q0.6 - This is the maximum laser power. At low speeds this will cut through most materials on our approved materials list.

F Command

The F command specifies the feed rate for all following moves. This would be the linear movement speed of the lens carriage. The speed effects the amount of cutting that the laser beam does to the material that it moves over. At a given laser power, a slower speed will cut deeper or burn more, and a faster speed will cut shallower or burn less. Testing has shown that above F1500, the precision of the laser carriage deteriorates to the point of visual artifacts being present in the work.

S Command

The S command specifies the number of pulses per unit of length. In any case that you want a continuous cut or etched line, this should be specified as S10000. The Inkscape Plugin uses S10000 as the default on all cases, except light engraving of paper. For light engraving of paper, a value of S1 is chosen so that it perforates instead of creating a continuous cut.