Cast Acrylic Sheet vs PMMA-HI
Polymer · grade comparison
Cast Acrylic Sheet and PMMA-HI are both polymer grades. Cast Acrylic Sheet is the stronger of the two: yield strength 72 MPa (10.4 ksi) against 48 MPa (6.96 ksi) for PMMA-HI, about 50% more; tensile strength follows at 75 MPa (10.9 ksi) vs 50 MPa (7.25 ksi). In exchange, PMMA-HI is the more ductile: elongation 30% versus 4.5% for Cast Acrylic Sheet. Cast Acrylic Sheet is stiffer (3.2 GPa vs 2.2 GPa) and Cast Acrylic Sheet runs hotter in service (80°C vs 72°C continuous).
Cast Acrylic SheetChoose it when strength drives the design, or when the part sees heat.
PMMA-HIChoose it when the part is bent, formed or impact-loaded.
Cast Acrylic Sheet vs PMMA-HI: 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.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Fracture Toughness (K_IC)
Izod Impact, Notched
Hardness, Shore D
Hardness, Rockwell M
Hardness, Rockwell R
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Water Absorption (Saturation)
Refractive Index
Light Transmission
Same in both: Water Absorption (24 h) 0.3%
Thermal
How each material carries heat and how hot it can run.
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Heat Deflection Temp. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Vicat Softening Point (B50)
Limiting Oxygen Index
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 · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Dissipation Factor (1 MHz)
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 · Surface Resistivity 1×10¹⁵ Ω · 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
Weldability
Formability (cold)
Polishability
Mold Shrinkage
Melt Flow Rate
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 2%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Same in both: 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-HI |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$ Standard | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Cast Acrylic Sheet vs PMMA-HI — frequently asked
Is Cast Acrylic Sheet stronger than PMMA-HI?
Yes. Cast Acrylic Sheet has a typical yield strength of 72 MPa (10.4 ksi) against 48 MPa (6.96 ksi) for PMMA-HI — about 50% more. Tensile strength is 75 MPa (10.9 ksi) vs 50 MPa (7.25 ksi).
Which is cheaper, Cast Acrylic Sheet or PMMA-HI?
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.
When should I choose Cast Acrylic Sheet over PMMA-HI?
Pick Cast Acrylic Sheet when strength drives the design, or when the part sees heat. Pick PMMA-HI when the part is bent, formed or impact-loaded.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Cast Acrylic Sheet and PMMA-HI 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.