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PMMA-HR vs PMMA-Optical

Polymer · grade comparison

PMMA-HR and PMMA-Optical are both polymer grades. Both yield at about 72 MPa — strength does not separate them. PMMA-Optical is the more ductile: elongation 4.5% versus 3.5% for PMMA-HR. PMMA-HR runs hotter in service (95°C vs 75°C continuous).

PMMA-HRChoose it when the part sees heat.

PMMA-OpticalChoose it when the part is bent, formed or impact-loaded.

PMMA-HR vs PMMA-Optical: properties

PMMA-HRPMMA-Optical

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

3.3 GPa0.48 Msi
3.2 GPa0.46 Msi

Shear Modulus

1.2 GPa0.17 Msi
1.2 GPa0.17 Msi

Bulk Modulus

5 GPa0.77 Msi
5 GPa0.73 Msi

Poisson's Ratio

0.38
0.37

Tensile Strength (Ultimate)

74 MPa10.7 ksi
72 MPa10.4 ksi

Yield Strength (0.2% offset)

72 MPa10.4 ksi
70 MPa10.2 ksi

Elongation at Break

3.5%
4.5%

Compressive Strength

115 MPa16.7 ksi
110 MPa16 ksi

Flexural Strength

115 MPa16.7 ksi
110 MPa16 ksi

Flexural Modulus

3.3 GPa0.48 Msi
3.2 GPa0.46 Msi

Shear Strength

58 MPa8.4 ksi
60 MPa8.7 ksi

Izod Impact, Notched

17 J/m0.32 ft·lbf/in
18 J/m0.34 ft·lbf/in

Hardness, Rockwell M

97 HRM
95 HRM

Same in both: Compressive Modulus 3 GPa0.44 Msi · Fracture Toughness (K_IC) 1.1 MPa·√m1 ksi·√in · Hardness, Shore D 90 Shore D

Physical

Density and transition temperatures.

Glass Transition (Tg)

125°C257 °F
105°C221 °F

Water Absorption (24 h)

0.3%
0.25%

Light Transmission

92%
93%

Same in both: Density 1.19 g/cm³0.04 lb/in³ · Water Absorption (Saturation) 2% · Refractive Index 1.492

Thermal

How each material carries heat and how hot it can run.

Thermal Expansion (CTE, 20–100 °C)

68 µm/m·K37.8 µin/in·°F
70 µm/m·K38.9 µin/in·°F

Max Service Temperature (continuous)

95°C203 °F
75°C167 °F

Heat Deflection Temp. @ 0.45 MPa

112°C234 °F
98°C208 °F

Heat Deflection Temp. @ 1.8 MPa

103°C217 °F
92°C198 °F

Vicat Softening Point (B50)

120°C248 °F
108°C226 °F

Limiting Oxygen Index

18%
18%

Max Service Temperature (short-term)

115°C239 °F
95°C203 °F

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.

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 · Dissipation Factor (1 MHz) 0.02 · Volume Resistivity 1×10¹⁵ Ω·cm · Surface Resistivity 1×10¹⁶ Ω · Comparative Tracking Index (CTI) 600 V

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

78 / 100
72 / 100

UV / Weathering Resistance

92 / 100
88 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

68 / 100
72 / 100

Weldability

55 / 100
60 / 100

Formability (cold)

60 / 100
70 / 100

Mold Shrinkage

0.45%
0.5%

Melt Flow Rate

1.8 g/10 min
8 g/10 min

Processing Melt Temperature (typ.)

255°C491 °F
245°C473 °F

Mold Temperature (typ.)

85°C185 °F
75°C167 °F

Same in both: Polishability 96 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

103 MJ/kg44,282 BTU/lb
105 MJ/kg45,142 BTU/lb

Embodied Carbon (primary production)

6.3 kg CO₂/kg
6.2 kg CO₂/kg

Embodied Water

250 L/kg30 gal/lb
280 L/kg33.6 gal/lb

Same in both: Typical Recycled Content 0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

62 kN·m/kg
61 kN·m/kg

Specific Stiffness (E / density)

2.8 MN·m/kg
2.7 MN·m/kg

Modulus of Resilience

785 kJ/m³
766 kJ/m³

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.

0.1110100123Density (g/cm³)Yield strength (MPa) — log scalePMMA-HRPMMA-Optical

Manufacturing and finishing

CapabilityPMMA-HRPMMA-Optical
Default condition——
Relative cost$$ Standard$$ Standard
Min. machined wall——
Best machined surface——

PMMA-HR vs PMMA-Optical — frequently asked

What is the difference between PMMA-HR and PMMA-Optical?

PMMA-HR and PMMA-Optical are both polymer grades. Both yield at about 72 MPa — strength does not separate them. PMMA-Optical is the more ductile: elongation 4.5% versus 3.5% for PMMA-HR.

Which is cheaper, PMMA-HR 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 welds better, PMMA-HR or PMMA-Optical?

PMMA-Optical. Its weldability rates good (60/100) against good (55/100) for PMMA-HR.

Ready to make it?

Upload a CAD file and FabDigit prices the part in PMMA-HR 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.