Cast Acrylic Sheet vs PMMA-Optical
Polymer · grade comparison
Cast Acrylic Sheet and PMMA-Optical are both polymer grades. Both yield at about 72 MPa — strength does not separate them. On the shop floor, PMMA-Optical forms better (very good vs poor).
Cast Acrylic Sheet vs PMMA-Optical: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Cast Acrylic SheetPMMA-Optical
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Shear Modulus
Bulk Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Compressive Strength
Flexural Strength
Fracture Toughness (K_IC)
Izod Impact, Notched
Hardness, Rockwell M
Hardness, Rockwell R
Same in both: Elastic (Young's) Modulus 3.2 GPa0.46 Msi · Poisson's Ratio 0.37 · Elongation at Break 4.5% · Compressive Modulus 3 GPa0.44 Msi · Flexural Modulus 3.2 GPa0.46 Msi · Shear Strength 60 MPa8.7 ksi · Hardness, Shore D 90 Shore D
Physical
Density and transition temperatures.
Glass Transition (Tg)
Water Absorption (24 h)
Refractive Index
Light Transmission
Same in both: Density 1.19 g/cm³0.04 lb/in³ · Water Absorption (Saturation) 2%
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Heat Deflection Temp. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Vicat Softening Point (B50)
Max Service Temperature (short-term)
Same in both: Thermal Conductivity 0.19 W/m·K0.11 BTU/hr·ft·°F · Specific Heat Capacity 1,470 J/kg·K0.35 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 70 µm/m·K38.9 µin/in·°F · Min Service Temperature -40°C-40 °F · Limiting Oxygen Index 18%
Electrical
Conductivity and insulation.
Dissipation Factor (1 MHz)
Surface Resistivity
Same in both: Electrical Resistivity 1×10¹³ Ω·m3.94×10²⁰ µΩ·in · Dielectric Strength 25 kV/mm635 V/mil · Dielectric Constant (1 MHz) 2.8 · Volume Resistivity 1×10¹⁵ Ω·cm · Comparative Tracking Index (CTI) 600 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
UV / Weathering Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Formability (cold)
Polishability
Mold Shrinkage
Melt Flow Rate
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Same in both: Weldability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Modulus of Resilience
Same in both: Specific Stiffness (E / density) 2.7 MN·m/kg · Thermal Diffusivity 0.1 mm²/s · Thermal Shock Resistance Index 0
Strength versus weight
Yield strength against density for every polymer grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | Cast Acrylic Sheet | PMMA-Optical |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$ Standard | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Cast Acrylic Sheet vs PMMA-Optical — frequently asked
What is the difference between Cast Acrylic Sheet and PMMA-Optical?
Cast Acrylic Sheet and PMMA-Optical are both polymer grades. Both yield at about 72 MPa — strength does not separate them. On the shop floor, PMMA-Optical forms better (very good vs poor).
Which is cheaper, Cast Acrylic Sheet or PMMA-Optical?
Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, Cast Acrylic Sheet or PMMA-Optical?
Cast Acrylic Sheet, by a small margin. Both rate very good for machinability — 80/100 against 72/100 for PMMA-Optical.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Cast Acrylic Sheet and PMMA-Optical side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.