Skip to content

Engraving Acrylic Perfectly

Engraving acrylic with a laser creates stunning, polished results that are perfect for signage, decorations, jewelry, and more. With some knowledge of the different types of acrylic and engraving techniques, you can achieve professional-quality finishes. Here’s how to get started and refine your acrylic engraving projects.

Types of Acrylic

There are two main types of acrylic used in laser engraving: Cast Acrylic and Extruded Acrylic. Both are laser-safe but behave differently when engraved or cut.

1. Cast Acrylic

  • How It’s Made: Liquid acrylic is poured between tempered glass sheets, hardens, and forms a sheet.
  • Engraving Finish: Produces a frosted, textured appearance when engraved.
  • Cutting: Cuts cleanly and has excellent optical clarity.
  • Best Uses: Ideal for signs, awards, and decorative items that require a frosted effect.

2. Extruded Acrylic

  • How It’s Made: Acrylic pellets are melted and pressed through a die at high pressure to form sheets.
  • Engraving Finish: Engraves with a smoother, clearer finish compared to cast acrylic.
  • Cutting: Softer and requires faster cutting speeds to prevent melting. Cut after engraving to avoid the material fusing back together.
  • Best Uses: Mirror acrylic and specialty finishes, especially for designs requiring a polished or clear engrave.

Engraving Orientation: Front vs. Back

You can engrave acrylic on either the front or back. The choice depends on the type of acrylic and the desired effect:

  • Front Engraving: Produces a frosted, textured surface.
  • Back Engraving: Flipping the acrylic and engraving the reverse side creates a polished, dimensional look. This technique is ideal for translucent, clear, or mirror acrylic.  When using this technique remember to flip your design so that you are engraving it reversed.
  • Reverse Engrave Technique: Engrave everything except the parts you want to stand out. For example, engraving the background while leaving the design clear will make the design shine.

Techniques for Enhanced Results

1. Defocused Engraving

  • Defocusing the laser slightly can result in a smoother and more even engraving.
  • Example: For ⅛” acrylic, set the laser focus to 0.3” instead of 0.12”.
  • Tip: Test small circles or squares with different focus settings to find the optimal focus for your specific piece of acrylic.

2. Dish Soap Method

Applying a thin layer of liquid dish soap can prevent residue buildup and minimize back flash.

  • Steps:
    1. Remove the masking from the engraving side.
    2. Apply a thin, even layer of liquid dish soap to the surface.
    3. Optional: Remove masking from the reverse side and apply dish soap there as well.
    4. Rinse the acrylic with water after engraving to remove soap and debris.

3. Masking

  • Remove the masking on the engraving side for a clean finish, or leave it on the back to protect the surface.  If you want to paint the engrave you can leave the front masking on to get a clean finish.
  • If engraving both sides, remove the masking from both and apply the dish soap method.

Engraving and Cutting Order

  • Engrave First, Cut Second: For extruded acrylic, always engrave before cutting. Cutting first can cause the edges to melt back together during engraving, making it difficult to remove.

Example Projects and Techniques

Avocado Example

  • Front Engraving: Produces a frosted texture.
  • Back Engraving: Results in a cleaner, sharper appearance.
  • Reverse Engraving: Engrave the background, leaving the design (like dragonflies) untouched to stand out and shine.

Dragonfly Example

Testing Settings

  • Use small test shapes (e.g., circles or squares) to try different speeds, power settings, and focus distances.
  • Adjust your laser settings for each new acrylic type or thickness.

Final Tips for Engraving Acrylic

  1. Use Air Assist: Reduces smoke buildup and keeps the engraving area clean.
  2. Clean the Laser Lens: Regular cleaning prevents residue buildup that can scatter the laser beam.
  3. Experiment: Different types of acrylic respond differently to engraving. Testing is key to achieving the best results.
  4. Rinse and Polish: After engraving, rinse the acrylic and dry it with a soft cloth for a polished finish.

Conclusion

Engraving acrylic offers endless creative possibilities when done correctly. By understanding the differences between cast and extruded acrylic, mastering focus settings, and using techniques like the dish soap method, you can achieve professional-quality results. Experiment, practice, and let your creativity shine through your acrylic projects.

Next article Glowforge CO2 Laser Cut Settings