Engraving slate with a laser requires precise settings to achieve optimal results while avoiding damage to the material. The ideal laser settings can vary based on the specific type of slate and the laser system being used, but here are some general guidelines:

• Power: Use a lower power setting, typically between 10% to 30%, depending on the wattage of your laser. Higher power can burn the slate instead of engraving.
• Speed: Set the engraving speed at around 200 to 500 mm/s. Slower speeds can create deeper engravings but may also cause more heat, which can damage the slate.
• Frequency: For CO2 lasers, a frequency of around 500 to 1000 Hz is effective. Lower frequencies can lead to better engraving quality.
• Passes: Multiple passes at lower power are often better than a single pass at high power. Start with 1-3 passes and adjust based on the desired depth.
• Cooling: Engraving should be done with adequate cooling to prevent overheating, which can warp the slate.

Always perform a test on a scrap piece of slate to fine-tune your settings before executing the final design.