Cutting 10mm acrylic with a CO₂ laser unlocks possibilities for signage, displays, and structural components—but uncontrolled melting can turn crisp edges into a warped, cloudy mess. Melted acrylic not only ruins aesthetics but weakens structural integrity. These evidence-based techniques will help you achieve clean, polished edges without the frustration of rework.

🧪 1. ​​Material Selection & Prep: The Foundation​​

• ​​Extruded Acrylic Only​​:
  Cast acrylic cracks under laser heat stress due to internal polymerization strains. ​​Use extruded acrylic exclusively​​—its uniform molecular structure resists stress fractures and melts more predictably.
• ​​Masking Matters​​:
  Keep protective film on during cutting to prevent surface scuffs from debris. Peel only if adhesive interferes with edge clarity.
• ​​Thickness Verification​​:
  Measure acrylic thickness at multiple points. Variations >0.2mm cause inconsistent focus, leading to partial melting.

⚙️ 2. ​​Machine Setup: Precision Is Non-Negotiable​​

• ​​Lens Selection​​:
  A ​​4.0" focal length lens​​ provides deeper penetration and a wider kerf, allowing molten material to eject cleanly. Short-focus lenses (1.5"–2.5") concentrate heat too narrowly, increasing melt risk.
• ​​Nozzle Optimization​​:
  Use a ​​10mm nozzle with the tip removed​​ to maximize airflow dispersion. Position 1–2mm above the acrylic surface to ensure gas penetrates the entire kerf depth.
• ​​Focus Calibration​​:
  Set the focus point ​​2mm below the material surface​​ for 10mm cuts. This balances energy distribution across the thickness, preventing top-edge melting or bottom-edge roughness.
• ​​Air Assist Pressure​​:
  ​​≥20 PSI compressed air​​ is critical. It cools the cut zone, ejects molten acrylic before it re-fuses, and suppresses flare-ups. Avoid oxygen—it ignites acrylic.

🔧 3. ​​Cutting Parameters: Dialing In the Sweet Spot​​

• ​​Multi-Pass Strategy​​:
  Single passes overload acrylic with heat. Use ​​2–3 passes​​:
  • ​​First Pass​​: 70% power, faster speed (e.g., 15 mm/s)—scores a guide channel.
  • ​​Final Pass​​: 90–100% power, slow speed (e.g., 5–8 mm/s)—cleans out melt residue.
• ​​Speed vs. Power Balance​​:
  High speed + low power causes incomplete cuts; low speed + high power melts edges. For 10mm extruded acrylic:

  Laser Power	Ideal Speed	Frequency
  60W	3–5 mm/s	5–8 kHz
  100W	8–12 mm/s	8–12 kHz
  150W+	15–20 mm/s	12–20 kHz
  Lower frequencies reduce heat buildup.

• ​​Pulse Control​​:
  For raster engraving, use ​​high speed (500+ mm/s) with ≤20% power​​ to avoid heat accumulation.

🛤️ 4. ​​Cut Path Design: Outsmarting Heat Buildup​​

• ​​Corner Relief​​:
  Add ​​0.5mm radius fillets​​ to sharp corners. This lets the laser maintain speed without dwelling (and melting) points.
• ​​Lead-In/Out Lines​​:
  Start and end cuts ​​3–5mm outside the contour​​ to prevent burn marks at entry/exit points.
• ​​Cut Sequencing​​:
  Cut inner features first, then outer contours. This prevents heat from warping the workpiece mid-cut.
• ​​Part Spacing​​:
  Maintain ​​≥10mm between parts​​ to dissipate heat and avoid warping adjacent edges.

🧼 5. ​​Post-Processing: Salvaging Perfection​​

• ​​Dross Removal​​:
  Gently scrape bottom-edge slag with a ​​wooden wedge​​ (metal tools scratch acrylic). Follow with ​​isopropyl alcohol​​ wipe.
• ​​Flame Polishing​​:
  Pass a ​​propane torch​​ 10–15cm quickly across edges. The brief heat exposure melts micro-fractures into clarity—​​1–2 seconds per 10cm​​ avoids bubbles or distortion.
• ​​Stress Relief​​:
  Anneal parts at ​​80°C for 2–4 hours​​ to relax internal stresses from cutting.

⚠️ ​​Critical Pitfalls to Avoid​​

• ​​Never use cast acrylic​​—internal cracking is inevitable.
• ​​Don’t skip air assist​​—even 10 seconds without airflow can melt kerf walls shut.
• ​​Avoid high-frequency pulsing​​ (>20kHz)—continuous wave melts less than rapid pulsing.

❓ ​​FAQs: Troubleshooting Melted Edges​​

• ​​Q​​: Why is my cut edge textured or cloudy?
  ​​A​​: Likely insufficient air pressure or focus drift. Verify nozzle clearance and refocus mid-job if cutting >30 minutes.
• ​​Q​​: Can I cut faster than recommended if I increase power?
  ​​A​​: No—speed protects against melting by limiting heat exposure. Excess power chars acrylic.

Clean 10mm acrylic cuts demand harmony between ​​material science​​, ​​precise optics​​, and ​​thermal management​​. Prioritize extruded acrylic, multi-pass patience, and aggressive air assist. When parameters align, CO₂ lasers produce edges rivaling polished glass—transforming thick acrylic from a thermal adversary into a canvas of precision.