Introduction
Acrylic (PMMA, also known as plexiglass) is a thermoplastic with high transparency, rich color options and excellent machinability, widely used in signage, craft displays, electronic device panels and lighting diffusers. There are two main machining routes: laser cutting/engraving and CNC precision cutting. This guide covers the characteristics, advantages and selection advice for both, so you can find the most suitable process for your acrylic parts.
1. Acrylic Material Basics
1.1 Types of acrylic
Extruded acrylic (XT): melt-extruded; uniform thickness, tight tolerances, lower price. Best for high-volume standardized products. Thickness 1.0–25 mm.
Cast acrylic (GS): cell-cast in molds; better optical properties and strength, available in thick sheets. Best for small-batch custom work and thick sections. Thickness 2.0–200 mm.
1.2 Physical properties
| Property | Typical value |
|---|---|
| Density | 1.19 g/cm³ |
| Light transmission | 92% (clear) |
| Rockwell hardness | M 85–90 |
| Continuous use temperature | 70–80 °C |
| Water absorption | 0.3% |
| Tensile strength | 70–100 MPa |
| Flexural strength | 100–120 MPa |
| Flame rating | HB (V-0 available on request) |
2. Laser Cutting and Engraving
2.1 How laser cutting works
Laser cutting focuses a high-energy-density beam on the acrylic, instantly melting, vaporizing or burning the material while an assist gas blows the molten debris away, producing a precise cut.
| Laser type | Power | Max thickness | Precision | Typical use |
|---|---|---|---|---|
| CO₂ laser | 60–150 W | ≤ 20 mm | ±0.1 mm | Signage / crafts |
| Fiber laser | 30–100 W | ≤ 6 mm | ±0.05 mm | Fine parts |
| UV laser | 10–30 W | ≤ 3 mm | ±0.02 mm | Fine engraving |
2.2 Advantages of CO₂ laser cutting
1. Smooth, flame-polished-like cut edges — vertical walls, often no secondary polishing needed. 2. High engraving resolution down to 0.01 mm for fine graphics. 3. Small heat-affected zone — edges show little or no yellowing. 4. No mechanical stress — non-contact process, no part deformation. 5. Any complex contour, no tooling required.
2.3 Process parameters
Cutting speed reference (CO₂ 100 W, 90° cut edge):
| Thickness | Recommended speed | Passes |
|---|---|---|
| 2 mm | 30–40 mm/s | 1 |
| 3 mm | 20–30 mm/s | 1 |
| 5 mm | 10–15 mm/s | 1 |
| 8 mm | 5–8 mm/s | 1–2 |
| 10 mm | 3–5 mm/s | 2 |
| 15 mm | 2–3 mm/s | 2–3 |
Engraving reference: depth 0.1–1.5 mm (adjustable) · speed 200–500 mm/s · resolution 500–1000 DPI.
2.4 Common laser problems and fixes
| Problem | Cause | Solution |
|---|---|---|
| Yellowed / burnt edge | Power too high or speed too slow | Reduce power or increase speed |
| Edge not vertical | Focus misadjusted | Recalibrate the focal point |
| Rough cut surface | Dirty or degraded optics | Clean or replace lenses |
| Thin sheet warps | Insufficient assist air | Increase air pressure |
| Thick sheet will not cut through | Insufficient power or speed too high | Slow down or add passes |
2.5 Engraving styles
Raster engraving: line-by-line scanning like a dot-matrix print; for filled patterns, text and images; depth 0.1–1.5 mm.
Vector cutting: follows the path outline; for shapes and text borders; can cut or score.
Layer engraving: multiple passes at different depths; creates 3D relief effects; common for awards and souvenirs.
3. CNC Precision Cutting
3.1 How CNC machining works
CNC (computer numerical control) machining removes material with high-speed rotating tools (mills, drills). CAM software programs the toolpath for precise cutting.
| Tool type | Diameter | Thickness range | Characteristics |
|---|---|---|---|
| Straight flute mill | 1–20 mm | 2–50 mm | General purpose, vertical walls |
| Tapered mill | 1–6 mm | 1–20 mm | Finishing, smooth walls |
| Drill bit | 1–12 mm | Through holes | Hole making |
| Chamfer mill | 1–8 mm | 45°–90° chamfers | Edge finishing |
3.2 Advantages of CNC machining
1. Highly vertical cut edges. 2. Wide thickness range, 0.5–200 mm. 3. Tight tolerances down to ±0.05 mm. 4. Complex 3D shapes: bevels, curves, relief carving. 5. Strong on thick stock — above 20 mm it beats laser on efficiency. 6. Friendly to follow-on processes: drilling, tapping, bonding.
3.3 Process parameters
Cutting reference (PCD/carbide tooling):
| Thickness | Spindle speed | Feed rate | Depth per pass |
|---|---|---|---|
| 2–5 mm | 18000–24000 RPM | 800–1500 mm/min | 1–2 mm |
| 5–10 mm | 12000–18000 RPM | 500–1000 mm/min | 2–3 mm |
| 10–20 mm | 8000–12000 RPM | 300–600 mm/min | 3–5 mm |
| Above 20 mm | 6000–8000 RPM | 200–400 mm/min | 3–5 mm |
3.4 Common CNC problems and fixes
| Problem | Cause | Solution |
|---|---|---|
| Chipped edges | Worn tool or excessive feed | Replace tool or reduce feed |
| Surface scratches | Tool runout or loose workpiece | Check spindle runout, clamp the part |
| Heat deformation | Accumulated cutting heat | Add coolant or compressed air |
| Dimensional deviation | Tool compensation not set | Set cutter radius compensation correctly |
| Rough bevels | Poor cutting parameters | Optimize speed-to-feed ratio |
4. Laser vs CNC: Side by Side
| Criterion | Laser cutting / engraving | CNC precision cutting |
|---|---|---|
| Max thickness | 20 mm (CO₂) | 200 mm |
| Edge quality | Smooth, near fire-polished | Smooth (may need finishing) |
| Precision | ±0.1 mm | ±0.05 mm |
| Minimum feature | 0.1 mm | 0.5 mm |
| Shape complexity | Any contour | Any contour |
| 3D capability | Limited (layer engraving) | Full 3D |
| Thick-stock efficiency | Low above 20 mm | High |
| Heat-affected zone | Slight yellowing | None |
| Best batch size | High-volume standardized | Small-batch custom |
| Cost | Lower | Moderate |
| Material waste | Low | Slightly higher |
Guidance: choose laser for thickness ≤10 mm, cosmetic edges and volume production; choose CNC for thickness >10 mm, 3D shapes and tight tolerances; combine both — rough out with CNC, finish details with laser.
5. Typical Applications
5.1 Signage and advertising
Laser: dimensional letters (5–15 mm acrylic cut into letter forms), illuminated signs (base + clear panel with built-in LEDs), lightbox panels (patterned thin sheet for backlighting).
5.2 Electronic device panels
CNC: precision panel cutouts to drawing, curved headphone housings, beveled display bezels for a premium look.
5.3 Crafts and gifts
Laser engraving: 3D layered engraving on awards and trophies, photo engravings converted to raster dots, personalized text and graphics from a single piece.
5.4 Display fixtures
Combined processes: display stands cut and blanked by CNC, laser-cut decorative patterns, custom-sized transparent covers with CNC cutting plus polishing.
6. Chaorong Acrylic Machining Services
| Service | Min size | Max size | Tolerance | Lead time |
|---|---|---|---|---|
| Laser cutting | 5 mm | 1220 × 2440 mm | ±0.1 mm | 1–2 days |
| CNC precision cutting | 50 mm | 2000 × 3000 mm | ±0.05 mm | 2–3 days |
| Laser engraving | Any | 1220 × 2440 mm | ±0.05 mm | 1–2 days |
| CNC 3D engraving | Any | 2000 × 3000 mm | ±0.1 mm | 3–5 days |
Optional finishing: polishing (cloth / flame / diamond) · bonding (solvent / UV adhesive) · silk screening (single or multi-color) · coating (color spray / UV coat).
Conclusion
Laser and CNC each have clear strengths — the right process depends on your thickness, precision, quantity and budget. Chaorong Electronics runs both laser cutting and CNC machining centers in-house, so we can recommend the optimal route for your part, made to drawing or sample, from a single piece.