Laser Engraving Settings for Acrylic on Diode Lasers: What Actually Works
Every settings guide you find for acrylic laser engraving was written for a CO2 laser. If you have a diode laser, an xTool D1 Pro, a Sculpfun, an ORTUR, almost anything with a blue diode module, you have probably tried those settings and gotten nothing, smoke, or a melted mess.
The reason is physics, not operator error, and once you understand it, the settings make sense.
Why Diode Lasers and Acrylic Are Complicated
A standard diode laser emits at around 450 nanometers, which is blue visible light. Clear acrylic is transparent to blue light. The laser passes through it the same way a flashlight passes through a glass of water. No absorption means no heat means no engraving.
CO2 lasers operate at 10,600 nanometers, which is infrared. Acrylic absorbs infrared efficiently, which is why CO2 settings work on clear acrylic and diode settings do not.
This has three practical consequences:
- Dark and opaque acrylic works well with a diode laser. Black acrylic absorbs the blue wavelength and engraves cleanly. Any dark, saturated color will work.
- Clear acrylic requires a workaround. You can engrave clear acrylic with a diode laser, but only after coating the surface with something that absorbs the beam. Marking spray is the most reliable method.
- Mirrored acrylic engraves from the back. The mirror coating on the reverse side is what the laser removes. You engrave through the clear front surface onto the reflective back, which means you do need a coating or workaround on the clear side if you are working front-to-back.
All the settings below account for this.
Products Referenced in This Guide
xTool D1 Pro 10W ($449) / 20W ($699)
The D1 Pro is the reference machine for this guide. The 10W is the practical choice for most acrylic work. The 20W cuts faster and thicker but is harder to control on engraving passes where you want fine detail.
Dark Acrylic Sheets, 3mm, 12×12 inch (Amazon, $18-25 for a 10-pack)
Black or dark-color cast acrylic in 3mm is the most versatile starting material for diode laser engraving. Extruded acrylic cuts differently than cast acrylic: cast produces cleaner edges but is more expensive.
xTool Black Marking Spray ($19.99 for 400ml)
The correct product for enabling diode laser engraving on clear acrylic. Washes off after engraving. Tempera paint is a free alternative that works with more cleanup involved.
Honeycomb Laser Bed, 400x400mm ($28-35 on Amazon)
Required for any cutting work. Also useful for engraving to prevent heat buildup on the material underside. Raises the acrylic off the solid base and allows fumes to clear.
Fume Extractor or Ventilation Fan
This is not optional with acrylic. Burning acrylic produces methyl methacrylate vapor and fine particulates. A 4-inch inline fan ducted to a window is the minimum. A purpose-built fume extractor with activated carbon filtration is better if you engrave regularly. Do not run acrylic projects in an unventilated space.
Settings Table: 3W, 10W, and 20W Diode Lasers on Three Acrylic Types
All speeds are in mm/min. All power percentages are of rated module power. Settings are starting points tested on 3mm cast acrylic. Extruded acrylic may require 5-10% lower power on cutting passes.
Air assist: Low for engraving passes (high air flow disperses the burn and lightens the engraving depth). High for cutting passes (clears fumes and smoke from the cut path).
| Acrylic Type | Diode Power | Engrave Speed | Engrave Power | Cut Speed (3mm) | Cut Power | Passes |
|—|:—:|:—:|:—:|:—:|:—:|:—:|
| Dark / Black Opaque | 3W | 2,000 mm/min | 80% | 100 mm/min | 100% | 4-5 |
| Dark / Black Opaque | 10W | 4,000 mm/min | 40% | 350 mm/min | 100% | 2-3 |
| Dark / Black Opaque | 20W | 6,000 mm/min | 25% | 700 mm/min | 100% | 1-2 |
| Clear + Marking Spray | 3W | 1,500 mm/min | 70% | N/A | N/A | 1 |
| Clear + Marking Spray | 10W | 3,000 mm/min | 45% | N/A | N/A | 1 |
| Clear + Marking Spray | 20W | 4,500 mm/min | 30% | N/A | N/A | 1 |
| Mirrored (engrave back) | 3W | 2,000 mm/min | 75% | N/A | N/A | 1 |
| Mirrored (engrave back) | 10W | 4,000 mm/min | 35% | N/A | N/A | 1 |
| Mirrored (engrave back) | 20W | 6,000 mm/min | 22% | N/A | N/A | 1 |
N/A for cut settings on clear and mirrored: Cutting clear acrylic with a diode laser requires so many passes that the result is typically melted and discolored. Use dark acrylic for cutting projects. Clear and mirrored are engrave-only materials with a diode setup.
Dark Acrylic: The Practical Starting Point
Black 3mm acrylic is the easiest material to start with on a diode laser and produces the most consistent results. The blue diode wavelength is strongly absorbed by dark pigment, which converts efficiently to heat at the surface.
On a 10W machine like the xTool D1 Pro, my go-to starting settings are 4,000mm/min at 40% power for engraving. This produces a light, clean mark that you can darken by slowing the speed or increasing power in 5% increments. I run test squares at these intervals before committing to a full design:
- 4,000mm/min / 35% power (slightly deeper)
- 4,000mm/min / 45% power (slightly lighter)
- 3,000mm/min / 40% power (slower, deeper)
The lightest result that still has clean edges and even depth is the sweet spot. Going too deep on acrylic removes material in a way that catches light inconsistently and looks rough rather than polished.
For cutting 3mm black acrylic on a 10W: 350mm/min, 100% power, 2-3 passes with air assist on high. First pass scores, second pass cuts through on most cast acrylic. Third pass handles any spots where the material resisted. Let the piece cool between passes if the cut path smells strongly.
Clear Acrylic with Marking Spray: The Workaround That Works
The xTool Black Marking Spray is a temporary coating that creates an opaque, heat-absorptive layer over the clear surface. The laser engraves into the coating, and where the coating is removed, the acrylic underneath is etched. You wash off the remaining coating afterward with water or a damp cloth.
The process is straightforward:
- Apply a thin, even coat of marking spray to the engraving surface. Hold the can about 10 inches away and sweep evenly. Let it dry 5 minutes.
- Run your engraving job at the Clear + Marking Spray settings above.
- Wipe off the residual spray with a damp cloth.
- The engraved areas will appear frosted or white against the clear acrylic background.
The result on clear acrylic is a frosted white design, not a dark mark. This works well for signs, plaques, and decorative items where the frosted effect is the point. For high-contrast dark marks on a light background, dark acrylic produces better results.
Tempera paint is a cheaper alternative. Brush it on, let it dry fully, engrave, and rinse off with water. The coverage is less even than spray, which sometimes produces inconsistent engraving depth. Worth trying before spending $20 on marking spray if you only need to test the technique.
One result I was not expecting: clear acrylic engraved with marking spray and lit from the edge with an LED strip looks exceptional for backlit signs. The frosted areas glow and the clear areas stay dark. Backlighting transforms the result from “frosted marks on plastic” to something much more polished.
Mirrored Acrylic: Engrave from the Back
Mirrored acrylic has a reflective coating on one face, typically on the back of a clear substrate. You engrave from the back, which removes the mirror coating and reveals the clear acrylic underneath. Viewed from the front, the design appears as clear areas against the mirror surface.
The process:
- Flip the sheet so the mirror side faces up on your laser bed.
- Run your engraving settings (see table above for mirrored).
- The laser ablates the coating, not the acrylic substrate itself.
Power levels are lower than dark acrylic because the mirror coating is thin and the goal is to remove it without going deep into the acrylic. At 10W, I found 35% power at 4,000mm/min removes the coating cleanly. At 40%+, the laser starts affecting the clear substrate and the result looks hazy rather than clear.
One thing to confirm before buying: some cheaper “mirrored” acrylic uses a thin metallic film that reflects differently at the diode wavelength. Test on a scrap piece before committing to a full sign. The coating should peel cleanly, not burn or discolor.
Safety: Acrylic Fumes Are Not Optional
Burning acrylic releases methyl methacrylate (MMA) vapor and fine particulate. MMA is an irritant at low concentrations and harmful with extended exposure. The particulate from laser cutting is sub-micron and reaches deep into the lungs.
Do not confuse acrylic with PVC. PVC releases chlorine gas when burned, which is a different and more acute hazard. Acrylic is not PVC, but it is still not safe to breathe.
For occasional engraving (a few projects per week): a 4-inch inline fan with flexible duct to an open window handles the fume load adequately. I run mine at medium speed during engraving and high during cutting.
For regular production use: an activated carbon fume extractor is the correct solution. Activated carbon captures MMA vapor. A standard particulate filter does not. The Vevor fume extractor (around $180-220) is a functional option at the lower end of the purpose-built range.
One rule I do not break: never leave a running laser job unattended with acrylic. The material melts rather than chars if the job fails mid-cut, and melted acrylic can ignite. A fire-resistant mat under the machine and a smoke detector in the workspace are not optional.
The Short Version
Use dark/black acrylic for most projects. It is the easiest, cleanest, and most predictable material for a diode laser and the only type where cutting works reliably.
Use clear acrylic with marking spray when the frosted-on-clear effect is specifically what you want. Budget extra time for the spray-and-wipe step, and expect that the result will look better backlit than under direct light.
Use mirrored acrylic for reflective signs and decorative items. Engrave from the back. Keep power low.
Run your machine’s power-speed test grid on a scrap piece of each material before starting any production project. The settings in the table above are starting points, not fixed values. Your specific machine, module age, and material batch will shift the optimal settings by 5-10% in either direction.
