CNC Acrylic Machining: The Ultimate Guide for Precision Plastic Parts

What is Acrylic (PMMA)?

Acrylic, or poly(methyl methacrylate) (PMMA), is a rigid, transparent thermoplastic. Known as a shatter-resistant alternative to glass, it’s available in pellets, sheets, or extruded forms. Key features include:

· High optical clarity (92% light transmission)

· UV stability for outdoor use

· Recyclability and chemical resistance

Why Choose CNC for Acrylic Machining?

CNC machining delivers precision-cut acrylic parts with:
✔ Tight tolerances (±0.1mm)
✔ Smooth edges (minimal post-processing)
✔ Complex geometries (laser cutting, milling, engraving)

Acrylic Properties for CNC

CNC Acrylic Machining Processes

1. CNC Milling & Routing

    ·  Best for: Signage, displays, prototypes

    ·  Tool Tip: Use single-flute carbide bits to reduce melting.

2. Laser Cutting

    ·  Best for: Intricate designs (e.g., retail fixtures)

    ·  Settings: Low heat input prevents edge yellowing.

3. Injection Molding

    ·  Best for: High-volume parts (e.g., lenses, knobs)

    ·  Mold Design: Include draft angles (1–2°) for easy release.

Top 5 CNC Acrylic Machining Tips

1. Minimize Heat Buildup

2. Use compressed air to cool cuts. Optimize feed rates (e.g., 1.5 m/min for 3mm sheets).

3. Avoid Cracking

4. Drill holes ≥3x material thickness from edges. Anneal parts post-machining for stress relief.

5. Achieve Optical Clarity

6. Polish edges with flame polishing or diamond buffing.

7. Select the Right Acrylic Type

8. Extruded: Cost-effective for simple shapes. Cell-cast: Superior for precision optics.

9. Use Solvent Bonding for seamless joints (e.g., Weld-On #4).

10. Applications of CNC Acrylic Parts