Laser cutting paper is a versatile technique used in crafting, packaging, design, and manufacturing. However, the success of a cut depends heavily on the paper's weight, measured in grams per square meter (gsm). Heavier papers like cardstock (200–400 gsm) require different settings and approaches compared to lighter, more delicate papers like vellum (typically 60–150 gsm). This article explores how to effectively laser cut papers across a range of weights, from thick cardstock to translucent vellum, using diode and CO₂ lasers. We'll cover optimal settings, challenges, and tips for achieving clean, precise results.

Understanding Paper Weights

Paper weight (gsm) indicates thickness and density:

• Lightweight Papers (40–100 gsm): Thin and flexible, like tissue or standard printer paper. Prone to burning, curling, or tearing.
• Medium-Weight Papers (100–200 gsm): Balanced, such as bond paper or lightweight cardstock. Versatile for most applications.
• Heavyweight Papers (200–400 gsm): Thick and sturdy, like cardstock or cover stock. More resistant to heat but may require higher power.
• Specialty Papers like Vellum: Often 60–150 gsm, translucent with a smooth or frosted finish, used for overlays or elegant designs.

Heavier papers absorb more energy, allowing for cleaner cuts with less risk of overburning, while lighter papers demand precise, low-heat settings to avoid damage.

Laser Cutting Cardstock (200–400 gsm)

Cardstock is a heavyweight paper ideal for sturdy projects like greeting cards, packaging, or 3D models. Its thickness provides durability but requires sufficient power to penetrate without charring the edges.

Challenges

• Thickness: May need multiple passes or higher power, increasing heat buildup.
• Edge Quality: Prone to slight scorching on dark or textured cardstock.
• Curling: Less common than in lighter papers, but uneven heating can cause warping.

Recommended Settings

• Diode Lasers (5–20 W):
  • Power: 20–50% (2–5 W for a 10 W laser).
  • Speed: 50–150 mm/s.
  • Passes: 1–3, depending on thickness.
  • Focus: Precise on surface; slight defocus (0.5 mm) for thicker stock to widen kerf and reduce burn.
• CO₂ Lasers (40–150 W):
  • Power: 10–25% (4–10 W for a 40 W laser).
  • Speed: 150–400 mm/s.
  • Passes: 1–2.
  • Focus: Surface-level for clean edges.

Tips

• Use air assist (1–2 bar) to clear debris and cool edges.
• Secure with a vacuum bed to prevent movement.
• For colored cardstock, reduce power by 5–10% on darker shades to minimize discoloration.

Laser Cutting Medium-Weight Papers (100–200 gsm)

Medium-weight papers, such as bond or lightweight cardstock, strike a balance between flexibility and strength, making them suitable for invitations, brochures, or prototypes.

Challenges

• Burning: Moderate risk; coatings or textures can exacerbate charring.
• Precision: Intricate designs may require fine-tuning to avoid incomplete cuts.
• Curling: Possible in humid environments due to moisture loss.

Recommended Settings

• Diode Lasers:
  • Power: 15–30% (1.5–3 W for a 10 W laser).
  • Speed: 100–250 mm/s.
  • Passes: 1–2.
  • Focus: Exact surface focus for sharp cuts.
• CO₂ Lasers:
  • Power: 8–15% (3.2–6 W for a 40 W laser).
  • Speed: 200–500 mm/s.
  • Passes: 1.
  • Focus: Surface or slight defocus for coated papers.

Tips

• Apply masking tape to protect surfaces from soot.
• Test cuts on scraps to adjust for specific textures (e.g., slower speeds for embossed papers).
• Maintain 40–60% humidity to reduce curling.

Laser Cutting Lightweight Papers (40–100 gsm)

Lightweight papers like tissue or printer paper are delicate, ideal for intricate lace-like designs or decorations, but they demand minimal heat to prevent damage.

Challenges

• Burning and Charring: High risk due to low density.
• Curling and Tearing: Easily warped or ripped during handling.
• Incomplete Cuts: Too low power may not penetrate fully.

Recommended Settings

• Diode Lasers:
  • Power: 5–15% (0.5–1.5 W for a 10 W laser).
  • Speed: 200–400 mm/s.
  • Passes: 1.
  • Focus: Precise; avoid over-focusing to prevent pinpoint burns.
• CO₂ Lasers:
  • Power: 3–8% (1.2–3.2 W for a 40 W laser).
  • Speed: 400–800 mm/s.
  • Passes: 1.
  • Focus: Surface-level.

Tips

• Use low-tack adhesive mats to secure without tearing.
• Employ air assist at low pressure (0.5–1 bar) to cool and stabilize.
• Lightly mist paper beforehand if dry to prevent excessive curling.

Laser Cutting Vellum (60–150 gsm)

Vellum is a translucent, parchment-like paper often used for elegant overlays, invitations, or artistic effects. Its semi-transparent nature and smooth finish make it unique, but it can melt or wrinkle under heat.

Challenges

• Melting: Synthetic vellums (plastic-based) may melt rather than cut cleanly.
• Transparency: Laser interaction can cause yellowing or haze.
• Fragility: Prone to curling and burning like other lightweights.

Recommended Settings

• Diode Lasers:
  • Power: 8–20% (0.8–2 W for a 10 W laser).
  • Speed: 150–300 mm/s.
  • Passes: 1.
  • Focus: Slight defocus (0.2–0.5 mm) to distribute heat.
• CO₂ Lasers:
  • Power: 5–10% (2–4 W for a 40 W laser).
  • Speed: 300–600 mm/s.
  • Passes: 1.
  • Focus: Surface for clarity.

Tips

• Distinguish between true vellum (calfskin, rare) and modern paper vellum; test for composition.
• Use masking tape or transfer paper to protect the surface.
• Cut in a well-ventilated area, as vellum may release fumes.

Comparison Table: Settings by Paper Weight

General Best Practices for All Paper Weights

• Test Runs: Always perform test cuts on identical material to fine-tune settings.
• Ventilation and Safety: Use fume extractors; wear wavelength-specific safety glasses.
• Maintenance: Clean laser optics regularly for consistent beam quality.
• Software: Use vector mode for cuts; adjust DPI (300–600) for detail.
• Scaling: CO₂ lasers handle heavier weights more efficiently due to higher power; diode lasers excel in precision for lighter papers.

Conclusion

From robust cardstock to delicate vellum, laser cutting different paper weights requires adapting settings and techniques to each material's properties. Heavyweights like cardstock benefit from higher power and slower speeds for penetration, while lightweights and vellum demand low energy and high speeds to prevent damage. By understanding these nuances and using tools like air assist and masking, you can achieve professional-quality cuts across the spectrum. Whether for hobbyist crafts or industrial production, experimenting with settings on your specific laser setup is key to mastering paper cutting.