Achieving high-quality results when engraving wood with a laser depends on optimizing three key settings: speed, power, and focus. These settings vary based on the type of wood, laser type, and desired outcome (e.g., deep engraving, light etching, or cutting). This guide provides general recommendations and considerations for dialing in the perfect settings for wood engraving.

1. Understanding Key Settings

• Speed: Measured in mm/s or in/s, speed determines how quickly the laser moves across the wood. Higher speeds produce lighter engravings, while slower speeds create deeper, darker results.
• Power: Expressed as a percentage of the laser’s maximum wattage, power controls the intensity of the laser beam. Higher power cuts deeper or engraves darker but risks burning the wood.
• Focus: The laser’s focal point must be precisely set to ensure crisp engravings. Incorrect focus can lead to blurry or uneven results.

2. General Guidelines by Wood Type

Different woods respond uniquely to laser engraving due to variations in density, grain, and resin content. Below are starting points for CO2 and diode lasers (adjust based on your machine’s wattage and manufacturer guidelines).

Softwoods (e.g., Pine, Cedar, Balsa)

• Characteristics: Less dense, easier to engrave, prone to burning if power is too high.
• CO2 Laser (40W–60W):
  • Engraving: Speed 200–300 mm/s, Power 20–40%
  • Cutting (1/8” thick): Speed 10–20 mm/s, Power 70–90%
• Diode Laser (5W–10W):
  • Engraving: Speed 100–150 mm/s, Power 50–80%
  • Cutting (1/16” thick): Speed 5–10 mm/s, Power 90–100%
• Focus: Set the focal point to the wood surface for engraving; slightly above for cutting to reduce charring.

Hardwoods (e.g., Oak, Maple, Walnut)

• Characteristics: Denser, requires higher power, produces cleaner engravings.
• CO2 Laser (40W–60W):
  • Engraving: Speed 150–250 mm/s, Power 30–50%
  • Cutting (1/4” thick): Speed 8–15 mm/s, Power 80–100%
• Diode Laser (5W–10W):
  • Engraving: Speed 80–120 mm/s, Power 60–90%
  • Cutting (1/8” thick): Speed 3–8 mm/s, Power 100%
• Focus: Precise surface focus is critical for detailed engravings; adjust slightly for thicker cuts.

Plywood and MDF

• Characteristics: Layered structure, may contain glue or resins that affect engraving. Watch for inconsistent results.
• CO2 Laser (40W–60W):
  • Engraving: Speed 200–350 mm/s, Power 15–35%
  • Cutting (1/4” thick): Speed 10–25 mm/s, Power 70–90%
• Diode Laser (5W–10W):
  • Engraving: Speed 100–200 mm/s, Power 40–70%
  • Cutting (1/8” thick): Speed 5–15 mm/s, Power 90–100%
• Focus: Ensure focus accounts for slight surface irregularities; test on a small area first.

3. Adjusting for Desired Results

• Light Etching: Use higher speeds (300–600 mm/s) and lower power (10–30%) for subtle designs or surface markings.
• Deep Engraving: Lower speeds (100–200 mm/s) and higher power (40–70%) for bold, deep engravings. Multiple passes may be needed.
• Cutting: Very low speeds (5–25 mm/s) and high power (70–100%) for clean cuts. Use air assist to reduce charring.
• Photo Engraving: High speeds (400–800 mm/s), low power (10–25%), and high DPI (300–600) for detailed grayscale images.

4. Focus Tips

• Manual Focus: Use the machine’s focus gauge or a calibration tool to set the laser head at the correct distance from the wood surface (typically 2–3 mm for CO2 lasers).
• Autofocus: If available, use autofocus for consistent results, especially on uneven surfaces.
• Test Focus: Run a small test engraving (e.g., a 5mm square) to confirm sharpness. Adjust focus in small increments (0.1–0.5 mm) if results are blurry.

5. Additional Considerations

• Test on Scrap: Always test settings on a scrap piece of the same wood to avoid ruining your project. Adjust incrementally (e.g., 5% power or 50 mm/s speed changes).
• Air Assist: Use air assist to blow away debris and reduce burn marks, especially on resinous woods like cherry or cedar.
• Ventilation: Wood engraving produces smoke and fumes. Ensure proper ventilation or use a fume extractor.
• Software Settings: Use software like LightBurn or RDWorks to fine-tune DPI, scan gaps, and pass counts for optimal results.
• Wood Preparation: Sand the wood surface for smoothness and remove any coatings or oils that could interfere with engraving.

6. Safety and Maintenance

• Monitor for Burning: High power or slow speeds can cause charring. Reduce power or increase speed if burning occurs.
• Clean the Lens: A dirty lens can diffuse the laser, reducing quality. Clean regularly with appropriate solutions.
• Check Alignment: Misaligned lasers can cause uneven engravings. Verify alignment periodically.

7. Recommended Starting Points

For a 40W CO2 laser engraving a 1/8” maple plank:

• Engraving: Speed 250 mm/s, Power 30%, DPI 300
• Cutting: Speed 15 mm/s, Power 85%, 1–2 passes
• Focus: Set to surface with a 2 mm focal length lens

For a 10W diode laser on 1/16” plywood:

• Engraving: Speed 120 mm/s, Power 60%, DPI 200
• Cutting: Speed 8 mm/s, Power 100%, 2–3 passes
• Focus: Adjust to surface using the laser’s focus tool

Conclusion

Finding the ideal laser settings for wood engraving requires experimentation and adjustment based on your specific machine, wood type, and project goals. Start with the recommended settings above, test on scrap material, and fine-tune speed, power, and focus to achieve clean, professional results. Always prioritize safety and proper maintenance to keep your laser engraver performing at its best.