Laser cutting is one of the most popular methods for processing acrylic (PMMA). The technology offers exceptional precision and produces polished edges right off the machine. In this guide, we'll explain how it works and when it's the best choice for your project.
How Does Laser Cutting Work?
Laser cutting uses a concentrated beam of light (typically CO2 laser at 10.6μm wavelength) to vaporize material along a programmed path. The laser beam is focused through a lens to achieve a spot size of about 0.1mm.
Key Parameters
Power: 60-150W for acrylic up to 20mm | Speed: 10-50mm/s depending on thickness | Focus: Optimal at material surface or slightly below
When the laser hits acrylic, the material doesn't burn - it vaporizes. This is why laser-cut edges on PMMA are smooth and polished, unlike wood or other materials that char.
Advantages of Laser Cutting
Advantages
- Polished edge finish (no post-processing)
- High precision (±0.1mm tolerance)
- Fast cutting of complex 2D shapes
- No contact with material (no deformation)
- Can engrave and cut in same pass
- Cost-effective for prototypes
Limitations
- 2D cutting only (no 3D milling)
- Max thickness ~20-25mm
- Not suitable for polycarbonate
- Heat-affected zone (HAZ)
- Fumes require extraction
- Material must be flat
Laser vs CNC: Quick Comparison
| Aspect | Laser Cutting | CNC Milling |
|---|---|---|
| Edge finish | Polished (ready to use) | Matte (requires polishing) |
| Precision | ±0.1mm | ±0.05mm |
| 3D machining | No | Yes (pockets, chamfers) |
| Max thickness | 20-25mm | Unlimited |
| Speed (simple shapes) | Very fast | Slower |
| Polycarbonate | No | Yes |
Best Applications for Laser Cutting
- POS displays - flat components with complex cutouts
- Signage - letters, logos, decorative panels
- Prototypes - quick turnaround for testing
- Engraved items - awards, nameplates, gifts
- Gaskets and spacers - precision flat parts
Materials That Work Well
- Cast acrylic (PMMA) - excellent results, best edge quality
- Extruded acrylic - good results, slightly less polished
- Acrylic mirror - cuts well, protect reflective side
- Colored/tinted acrylic - all colors work equally well
Pro Tip
Always use cast acrylic for the best edge quality. Extruded acrylic is cheaper but tends to have more internal stress that can cause micro-cracks during cutting.
When NOT to Use Laser
- Polycarbonate (PC) - absorbs laser poorly, yellows and burns
- PVC - releases toxic chlorine gas
- Parts thicker than 25mm - edge quality degrades
- 3D features needed - laser is 2D only
- Threads/tapping required - use CNC instead
Summary
Laser cutting is the go-to technology for flat acrylic parts up to 20mm thick. The polished edge finish eliminates post-processing, making it cost-effective for both prototypes and production runs.
Choose laser when you need:
- 2D parts with complex shapes
- Polished edges without extra work
- Fast turnaround
- Engraving combined with cutting