PMMA (Acrylic) Machining
Polymethyl methacrylate (PMMA), commonly known as acrylic or Plexiglas, offering exceptional optical clarity, UV resistance, and excellent machinability for optical, medical, and display applications.
Material Properties
1.17-1.20
g/cm³
160
°C
70-80
MPa
3.1-3.3
GPa
92
%
1.49
M97-M100
0.19
W/m·K
Machining Recommendations
Recommended Methods
CNC milling, turning, drilling, laser cutting, polishing
Tool Materials
Sharp carbide or high-speed steel tools; single-flute or two-flute end mills preferred
Cutting Speeds
200-600 m/min (high speed to minimize heat buildup)
Feeds
0.05-0.2 mm/rev (light feeds to prevent chipping)
Coolant
Dry machining or compressed air; avoid water-based coolants that may cause crazing
Machinability
Good – brittle nature requires sharp tools and careful fixturing to prevent cracking
Surface Finish
Ra 0.1-0.4 μm achievable; flame or diamond polishing can produce optical-grade clarity
Application Case Studies
Optical Lens Arrays for Imaging Systems
Industry: Optics & Photonics
Challenge
Precision PMMA lens arrays for industrial vision systems requiring 92%+ light transmittance and sub-micron surface roughness
Solution
Implemented diamond-turning process followed by optical polishing, with CMM verification of form accuracy
Result
Achieved Ra 0.05 μm surface finish and 99.2% optical transmission; supplied 20,000+ lenses annually
Medical Microfluidic Chips
Industry: Medical & Life Sciences
Challenge
PMMA microfluidic channel plates for diagnostic devices requiring channel widths of 100–500 μm with smooth walls
Solution
Utilized precision micro-milling with 0.1 mm end mills and solvent bonding for chip assembly
Result
Achieved channel dimensional accuracy within ±5 μm; passed biocompatibility testing per ISO 10993
Display Lightguide Panels
Industry: Consumer Electronics
Challenge
Large-format PMMA lightguide panels for LCD backlighting requiring uniform light distribution and tight thickness tolerance
Solution
CNC-machined microstructure dot patterns on panel surface combined with precision edge polishing
Result
Achieved luminance uniformity of 95% and supplied 50,000+ panels per year to display manufacturers
Architectural Decorative Panels
Industry: Architecture & Interior Design
Challenge
Custom-shaped PMMA decorative panels with engraved patterns for high-end retail environments
Solution
CNC engraving combined with LED edge-lighting design for dramatic visual effect
Result
Delivered 500+ custom panels with zero defect rate; reduced installation time by 30%
Protective Covers for Scientific Instruments
Industry: Laboratory & Scientific
Challenge
UV-resistant PMMA enclosures for sensitive laboratory instruments requiring chemical resistance and optical clarity
Solution
Selected UV-stabilized PMMA grade and implemented precision CNC machining with solvent-welded joints
Result
Extended instrument service life by 3× compared to standard polycarbonate covers
Technical Specifications
Available Forms
- Cast sheets
- Extruded sheets
- Rods
- Tubes
- Blocks
- Optical-grade blanks
1mm to 200mm thickness; sheets up to 2000×3000 mm
Tolerances±0.01mm to ±0.05mm (standard); ±0.005mm for optical applications
Lead Times1-2 weeks for standard orders; 3-5 days for prototypes
Quality StandardsFrequently Asked Questions
What is the difference between cast and extruded PMMA?
Cast PMMA offers superior optical clarity, tighter thickness tolerances, and better resistance to solvent crazing, making it preferred for optical and display applications. Extruded PMMA is more cost-effective for general-purpose parts where optical perfection is not critical.
Can PMMA be machined to optical-grade surface finish?
Yes. Using diamond-turning or multi-step polishing (mechanical followed by flame or chemical polishing), we can achieve Ra < 0.05 μm surface roughness suitable for optical lenses and light guides.
How do you prevent cracking or chipping during PMMA machining?
We use sharp, freshly ground tooling, light feed rates, and proper fixturing to distribute clamping forces. Annealing the material before machining also reduces internal stress and cracking risk.
Is PMMA suitable for medical device applications?
Yes. Medical-grade PMMA is biocompatible per ISO 10993 and is widely used in intraocular lenses, bone cement, dental prosthetics, and microfluidic diagnostic chips. We can provide full material traceability and biocompatibility documentation.
What bonding methods are available for PMMA assemblies?
PMMA can be joined using solvent bonding (methylene chloride or chloroform), UV-curable adhesives, or mechanical fastening. Solvent bonding produces optically clear, nearly invisible joints when done correctly.
Can PMMA be coated or printed on?
Yes. PMMA accepts UV-curable coatings, hard coats for scratch resistance, anti-reflective coatings, and screen or pad printing. We offer in-house coating services for common requirements.
What is your lead time for PMMA parts?
Prototype quantities are typically ready in 3-5 business days. Standard production orders ship within 1-2 weeks. Rush services are available for time-critical projects.
Can PMMA replace glass in my application?
In many cases, yes. PMMA transmits 92% of visible light versus ~91% for standard glass, weighs 50% less, and is far more impact-resistant. It is an excellent glass substitute for displays, windows, and optical components where weight and safety matter.
Related Services
CNC Milling
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CNC Turning
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CNC Drilling
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Advanced Machining
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