Opal and coloured PMMA
Frequently asked questions
Can Opal and coloured PMMA be laser cut?
Yes: Opal and coloured PMMA can be laser cut. Adequate extraction/ventilation is required.
Can Opal and coloured PMMA be CNC machined?
Yes: Opal and coloured PMMA can be CNC machined.
Is Opal and coloured PMMA food safe?
No, Opal and coloured PMMA is not considered food safe.
Physical properties
| Density | 1170.0–1200.0 kg/m³ |
|---|---|
| Tensile strength | 70.0 MPa |
| Glass transition (Tg) | 102.0 °C |
| Thermal expansion | 70.0 µm/m·K |
| Moisture absorption | Low |
Laser processing
Releases methyl methacrylate monomer (MMA) like transparent PMMA. The characteristic pungent odour indicates vapours that need venting. Not acutely toxic but irritating to eyes and respiratory tract with prolonged exposure. Pigments may add minor compounds: forced ventilation always recommended.
CO₂: Excellent CO2 laser cutting, identical to transparent cast PMMA. Glossy, clean edges on most colours. Optimal speed and power may vary slightly depending on the pigment (dark colours absorb more energy). Engraving produces a matte effect on the engraved background, with visual contrast varying according to the base colour.
Diode: Behaviour strongly colour-dependent: dark colours (black, dark blue, dark red) absorb the diode laser wavelength (~450nm) and are engravable and often cuttable. Transparent PMMA and light/opal colours reflect the diode laser and are not workable. Always test on a sample first.
Fiber: Not suitable for cutting. Fibre engraving is possible on dark-coloured surfaces but is not the primary technique for this material.
CNC / milling processing
Identical to transparent cast PMMA: excellent CNC machinability. Clean, sharp chips, good surface finish with sharp single- or double-flute geometry bits. Air cooling sufficient.
Plotter and thermoforming
Post-processing
Sanding: Sanding identical to transparent PMMA. Wet sequence: 180 → 320 → 600 → 1000 → polishing with abrasive paste. Dark colours show white scratches with coarse grits: start gently.
Primer: Not necessary for painting if the surface has been previously degreased. For acrylic paints adhesion is direct.
Gluing: Bondable with acrylic cement (chloroform, dichloromethane or PMMA-specific cements). Chemical welding produces invisible joints. Cyanoacrylate works but leaves whitish residues if it evaporates on the surface.
Over time: Pigments may fade over time with prolonged UV exposure, at varying rates depending on the pigment type. UV-stable (inorganic) colours hold up much better than organic ones. Opal PMMA with TiO2 diffuser is photostable.
Common defects
- Transparent PMMA cannot be engraved with a diode laser — a common maker error
- Crazing (micro-cracks) if exposed to aggressive solvents or combined mechanical stress
- Brittle edges — laser cutting produces glossy edges that are sensitive to impact if not chamfered
Safety
Recommended PPE: safety_glasses
Same precautions as transparent PMMA. MMA vapours during laser cutting are irritating: ventilate. The material is not classified as hazardous in solid state.
Availability and formats
Commercial formats: sheets 2–20mm (1000×2000mm format), discs, coloured transparent tubes
Related materials
Sources
- Evonik Plexiglas — Technical data sheet colored/opal sheets
- Datasheet tecnici Röhm GmbH PMMA colored grades
Information on compatibility, processing parameters and safety is purely indicative. MakerSpecs accepts no liability for damage to persons or property arising from the use of this data. Always check the safety rules and the manufacturer's official manuals before carrying out any processing.