Acrylic is one of the most useful materials for a CO2 laser cutter. It can be turned into signs, display stands, templates, enclosures, ornaments, product tags, lighting panels, and many other finished products. But clean acrylic cutting is not about finding one “magic” speed-and-power number. The best result depends on the acrylic sheet, thickness, focus, airflow, exhaust, optics, and the condition of the laser system.
This guide explains a repeatable way to find reliable 40W CO2 laser acrylic settings without guessing. The goal is simple: get a complete cut with the fastest practical speed, the least unnecessary heat, and a smooth edge while keeping the process controlled and safe.
Why a 40W CO2 Laser Works Well for Acrylic
CO2 lasers are widely used for cutting and engraving non-metal materials. A typical CO2 laser operates around 10.6 µm in the infrared spectrum, and acrylic is a common material processed with this type of laser. For a desktop or workshop machine, 40W is a practical power level for signs, crafts, prototypes, personalization, and small-batch production.
The Carverall C1 40W CO2 Laser, for example, combines a 40W CO2 tube with a 620 × 350 mm work area, water cooling, air assist, a honeycomb bed, and LightBurn compatibility. Those supporting systems matter because acrylic cutting quality depends on more than laser power alone.
Do Not Copy Acrylic Settings Blindly
Settings posted online can be useful as references, but they should not be treated as guaranteed values. Two sheets that both look like “3 mm acrylic” can behave differently because of formulation, manufacturing method, color, additives, surface condition, or actual thickness. Machine condition also matters: dirty optics, poor focus, reduced tube output, weak airflow, or an uneven work surface can change the result.
A better approach is to use a small offcut from the same sheet or batch and run a controlled material test. LightBurn includes a Material Test generator that can vary speed, power, passes, and other parameters in a test grid. LightBurn also recommends starting with the laser manufacturer’s settings when available, then testing when those values need adjustment.
Before Cutting Acrylic: 6 Checks That Affect Edge Quality
1. Confirm the material
Only process materials you can positively identify and that are approved for laser use by the material supplier and your laser manufacturer. Do not put unknown plastics into a laser just because they look similar to acrylic. Different plastics can generate very different fumes and residues when heated.
2. Check the acrylic thickness
Measure the sheet instead of relying only on the label. Even a small thickness difference can change the energy required to cut through consistently. If you change thickness, repeat the material test.
3. Clean the optics
Dust or residue on mirrors and lenses reduces the energy reaching the workpiece and can make previously reliable settings stop cutting cleanly. Follow your machine’s maintenance procedure and avoid touching optical surfaces directly.
4. Set the correct focus
Focus strongly affects kerf width, edge quality, and cutting efficiency. Start with the machine’s recommended focal position. If a job is close to cutting through but the edge is not clean, run a small focus test before making large power changes.
5. Turn on cooling, airflow, and exhaust
Do not treat the laser tube, air assist, and exhaust as separate accessories. They are part of the cutting process. Cooling protects the CO2 laser system, airflow helps control debris and flare-ups around the cutting zone, and extraction removes smoke and fumes from the enclosure.
OSHA’s technical guidance on laser hazards specifically notes the importance of adequate ventilation for fumes and vapors produced by laser cutting and other laser-material interactions. See the OSHA Technical Manual on laser hazards for general workplace safety guidance.
6. Make sure the sheet is flat
If acrylic bows upward or sits unevenly, the distance from the lens changes across the job. That can create areas that cut well and areas that do not. Place the sheet securely on the work surface without creating an obstruction in the beam path.
A Practical Workflow for Finding 40W CO2 Laser Acrylic Settings
Instead of publishing one universal settings chart, use the following workflow. It produces settings that are specific to your machine and your acrylic.
- Use a small sample from the same acrylic sheet. A different color or batch can behave differently.
- Start from the machine manufacturer’s recommended range. Do not assume that a setting from another laser transfers directly to your system.
- Create a speed-and-power test grid. In LightBurn, open Laser Tools → Material Test and choose a CO2 cutting preset or build your own range.
- Keep the first test simple. Use one pass initially so you can clearly see how speed and power affect the cut.
- Frame the test before running it. Confirm that the test area is fully inside the scrap piece and clear of clips or other objects.
- Run the test while actively monitoring the machine. Never leave a laser job unattended.
- Inspect the results. Look for the fastest box that cuts completely through while leaving a clean edge with minimal excess heat.
- Save the result. Record material name, color, measured thickness, speed, power, passes, focus method, and any airflow notes.
Important: pay attention to units. A value entered in mm/s is not the same as the same number entered in mm/min. LightBurn explicitly warns that mixing speed units can create dramatically different laser output conditions. Before copying any setting, confirm the unit used by the source and your device profile.
How to Read the Results of an Acrylic Material Test
A good acrylic cutting setting is not simply the box with the highest power. The best setting is usually the combination that provides a reliable through-cut without keeping the beam over the material longer than necessary.
If the acrylic does not cut through
- Verify focus before increasing power.
- Check whether the optics are clean.
- Reduce speed in small increments and test again.
- If appropriate for your machine, test additional passes.
- Confirm that your power setting stays within the operating guidance for your laser tube and power supply.
If the edge looks overly melted or rounded
- Try increasing speed slightly.
- Reduce unnecessary power.
- Recheck focus.
- Confirm that the sheet is flat and that airflow/exhaust are operating correctly.
If one area cuts and another does not
- Check whether the acrylic is warped.
- Verify the work surface is level.
- Inspect the optical path and focus.
- Repeat the test in another part of the sheet to rule out material variation.
Speed, Power, and Passes: What Each Setting Changes
Speed
Slower movement gives the laser more time to deliver energy into the cut. That can help with thicker material, but going unnecessarily slow also increases heat around the cut. When several settings cut through successfully, the faster clean result is generally the better starting point.
Power
More power increases the energy delivered to the material, but “more” is not automatically “better.” Use enough power to achieve a reliable cut without exceeding the operating limits recommended for your laser system. On glass-tube CO2 machines in particular, the percentage shown in software should not be treated as a universal measure of safe tube current.
Passes
Multiple passes can help when one pass does not cut through, but they can also add heat and widen the cut. Test both the number of passes and the speed rather than assuming that repeated passes are always the best answer.
Focus and Kerf Matter More Than Many Beginners Expect
The laser does not create a zero-width line. The removed material forms a narrow cut path called the kerf. Kerf size depends on the optical system, focus, material, and settings. If you are making press-fit parts, tabs, slots, boxes, or dimensional assemblies, a small kerf difference can affect the final fit.
For a new acrylic project, first optimize for a clean through-cut. Then cut a small measurement test, such as a square or slot sample, and measure the actual result. Use that real measurement to refine your design rather than assuming a fixed kerf value for every acrylic sheet.
Air Assist and Exhaust for Acrylic Cutting
Air assist helps keep smoke and debris away from the lens and cutting area, while exhaust removes airborne by-products from the enclosure. The ideal airflow can depend on the machine and the visual finish you want, so use the airflow system recommended for your laser and make small adjustments only after you have a stable baseline.
The C1 includes an air pump and water-cooling system, so when building a repeatable acrylic workflow, treat “air on, cooling on, exhaust on” as part of the job setup rather than something to remember after the laser has started.
Step-by-Step: Cutting an Acrylic Project in LightBurn
- Import or create the vector design. Use clean closed paths for cut lines.
- Assign cut lines to a Line layer. Confirm that engraving layers and cutting layers use separate settings if the project includes both.
- Place the acrylic flat on the bed. Check that the cutting path does not intersect hold-down hardware.
- Set focus. Follow the focusing method supplied with your machine.
- Start cooling, air assist, and exhaust.
- Load a tested material setting. If this is a new sheet, run a Material Test first.
- Preview and frame the job. Confirm size, position, and cut order.
- Start the job and stay with the machine. Watch for unexpected flame, excessive smoke, or movement of the material.
- Inspect the cut before removing the full sheet. If parts do not separate cleanly, stop and adjust rather than forcing them out.
- Record the final setting. Build your own material library over time.
Common Acrylic Cutting Problems and Fixes
| Problem | Likely Causes | What to Test Next |
|---|---|---|
| Does not cut through | Speed too high, insufficient power, poor focus, dirty optics, thicker-than-expected sheet | Refocus, clean optics, reduce speed gradually, then test power or passes within machine guidance |
| Edge is heavily melted | Too much heat or too much dwell time | Increase speed slightly, reduce unnecessary power, verify focus |
| Cut quality changes across the sheet | Warped material, uneven bed, focus variation, optical alignment issue | Flatten the sheet, check bed level and focus, inspect the optical path |
| Excess smoke inside the enclosure | Insufficient extraction or blocked airflow | Stop the job, inspect exhaust flow and ventilation before continuing |
| Unexpected flame | Material behavior, excessive heat, airflow issue, contaminated surface | Stop immediately, verify material and settings, and do not resume until the cause is understood |
Can the Carverall C1 Cut Acrylic?
Yes. The Carverall C1 is a 40W CO2 laser designed for materials including acrylic, wood, leather, paper, fabric, glass, and other compatible non-metal materials. Its 620 × 350 mm work area gives more room than many compact desktop machines, while LightBurn compatibility makes it easy to create material tests and save repeatable cutting parameters.
Actual cutting capability depends on the acrylic itself, sheet thickness, optical condition, focus, airflow, and chosen settings. For that reason, a tested material library is more valuable than a single universal “40W acrylic setting.”
FAQ: 40W CO2 Laser Acrylic Settings
What power and speed should I use for acrylic on a 40W CO2 laser?
Use your machine manufacturer’s recommended starting range, then run a speed-and-power material test on the same acrylic sheet. There is no single reliable value for every color, thickness, and machine condition.
Should I use one pass or multiple passes?
Start by testing one pass. If a clean through-cut is not possible within the recommended operating range, compare slower speed with additional passes. Multiple passes can help, but they may also increase heat and kerf.
Do I need air assist when cutting acrylic?
Use the airflow system recommended for your machine. Air assist helps manage smoke, debris, and flare-ups around the cutting zone and helps keep contamination away from the lens. Adjust only after you have a safe, repeatable baseline.
Why does my acrylic cut look different after I changed sheets?
Different sheets can vary in formulation, color, actual thickness, and surface condition. Treat a new batch or thickness as a new material and run a small test before starting a full-size job.
Can LightBurn automatically find the best acrylic settings?
LightBurn cannot know a single perfect setting in advance, but its Material Test generator makes comparison much faster by creating a grid that varies selected parameters. You can then choose the cleanest result and save it to your material library.
Build a Material Library Instead of Chasing “Magic Numbers”
The fastest way to improve acrylic cutting is to stop treating each project as a new experiment. Once you find a clean result, save the exact material, thickness, color, speed, power, passes, focus method, and airflow notes. After a few projects, you will have a settings library based on your own machine rather than someone else’s.
If you are building signs, personalized products, display pieces, prototypes, or small-batch acrylic products, explore the Carverall C1 40W CO2 Laser or browse more C1 CO2 laser tutorials for practical setup, material, and maintenance guides.
