CNC machining transforms Poly(methyl methacrylate) – more commonly known as Acrylic or PMMA – from a raw sheet or block into a high-precision, optically clear component. Unlike injection molding, which requires expensive tooling, CNC machining is ideal for prototyping, low-to-medium volume production, and complex parts that demand exceptional clarity and dimensional stability. This versatile process allows for the creation of everything from intricate prototypes to robust end-use parts with a brilliant, glass-like finish.
KEY BENEFITS
CNC machining unlocks the full potential of PMMA, offering a unique combination of aesthetic and functional advantages.
| Benefit | Description |
|---|---|
| Optical Clarity & Gloss | PMMA transmits light more effectively than glass, offering crystal-clear transparency and a brilliant, high-gloss surface finish that is ideal for lenses, displays, and aesthetic covers. |
| Excellent Weatherability | Highly resistant to UV light and environmental weathering, making it perfect for outdoor applications like automotive lights and signage without yellowing or degrading. |
| High Strength & Stiffness | Offers a superior strength-to-weight ratio compared to standard plastics, providing dimensional stability and impact resistance (6-8x that of glass). |
| Ease of Fabrication | PMMA is a soft, stable plastic that machines beautifully, allowing for tight tolerances, complex geometries, and smooth edges with minimal post-processing. |
| Chemical & Solvent Bonding | Parts can be easily and invisibly joined using solvent-based cements (like Weld-On), creating strong, seamless assemblies that appear to be a single piece. |
APPLICATIONS
The properties of machined PMMA make it the material of choice across a diverse range of industries.
| Industry | Part Application Examples |
|---|---|
| Medical & Life Sciences | Fluidic chambers, cuvettes for spectrometry, inspection windows, surgical device prototypes, and diagnostic equipment housings. |
| Automotive & Aerospace | Light guides, interior lens covers, aircraft cockpit displays, instrument panels, and prototype tail light assemblies. |
| Electronics & Consumer Goods | Protective covers for touchscreens and displays, light pipes for LED indicators, jigs and fixtures for assembly, and high-end product prototypes. |
| Architecture & Retail | Scale architectural models, intricate signage, custom light fixtures, point-of-purchase displays, and decorative panels. |
| Industrial & Optics | Inspection windows, gauge covers, lenses, reflectors, and optical light guides for sensors and machinery. |
TECHNICAL SPECIFICATIONS
This table provides essential data for engineers and designers to specify and design parts for CNC machining in PMMA.
| Property | Value / Description | Test Method |
|---|---|---|
| General Material Name | Acrylic, Polymethyl Methacrylate (PMMA) | – |
| Machining Surface Finish | Very Good to Excellent (can be polished to optical clarity) | – |
| Light Transmittance | ~92% (Superior to glass) | ASTM D1003 |
| Tensile Strength | 65 – 70 MPa | ASTM D638 |
| Flexural Strength | 90 – 110 MPa | ASTM D790 |
| Impact Strength (Izod Notched) | 0.4 – 0.6 ft-lb/in | ASTM D256 |
| Continuous Service Temperature | 70 – 90°C | – |
| Density | 1.18 – 1.19 g/cm³ | ASTM D792 |
| Recommended Feed Rate | High (Soft Material) | Machining Guideline |
| Recommended Cutting Tools | Sharp, multi-flute end mills (2-3 flutes) for plastics; Up-cut spirals for clean top edges. | Machining Guideline |
| Cooling | Compressed Air preferred. Coolant/Mist can be used but may require post-machining cleaning. | Machining Guideline |
Disclaimer: The values provided are typical and can vary between specific PMMA grades (e.g., cast vs. extruded). Always consult the material datasheet for critical applications.