How do I run a laser power and speed test grid, and how do I read it?

Why you need one

Published settings rarely transfer between machines. As an example, Sienci lists 3 mm plywood cutting on its 7 W LaserBeam at 2.2 mm/s, 100% power and 3 passes with a 1 mm Z step, while Opt Lasers lists 3 mm plywood on its XT8 head at 22.5 mm/s, 100% power and 1 pass. Opt Lasers states that a speed value without the other conditions is not enough to reproduce a result.

Build the grid in the software

1. Draw a small grid of equal squares on scrap of the exact job material. Label the columns with power values and the rows with speeds.
2. Create one Laser Cut - Fill toolpath per square using the Hatch Fill strategy. Keep Stepover and Hatch Angle the same for every square.
3. On each toolpath, type that square's Power and Move Speed. Edits on the form do not change the stored tool, so the database entry stays clean.
4. For a cutting test, use short lines with the Cut On strategy at a range of speeds, and note which ones cut through.
5. Save all of the toolpaths and burn the grid in one run.

Read it

• Engraving: pick the square with the tone you want and crisp edges, not the darkest one. Sienci's guide notes that lower speed gives a deeper, darker burn.
• Cutting: pick the fastest line that cuts cleanly through. Sienci suggests that lower power and a smaller Z step with more speed and more passes gives a cleaner edge.
• Change one variable at a time between tests, which is the method Opt Lasers recommends.

Record it

Opt Lasers lists what must be written down with any result: material and supplier, thickness, feed rate, power, number of passes, working distance (focus), and the air assist setup.

Pro tips

• Save the winning square as a laser tool for that material, then set its Maximum Burn Rate so the preview matches. See the entry on setting up a laser tool.
• Rerun the test when you change the lens, the focus distance or the air assist, since each one shifts the result.