FabDigit

PTMT vs PETG and 2 more: properties

PTMTPETGPBTPET

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

2.6 GPa0.38 Msi
2.1 GPa0.3 Msi
2.6 GPa0.38 Msi
3.1 GPa0.45 Msi

Shear Modulus

0.95 GPa0.14 Msi
0.77 GPa0.11 Msi
0.93 GPa0.13 Msi
1.1 GPa0.16 Msi

Bulk Modulus

4 GPa0.58 Msi
4 GPa0.61 Msi
5 GPa0.65 Msi

Tensile Strength (Ultimate)

55 MPa8 ksi
50 MPa7.3 ksi
55 MPa8 ksi
82 MPa11.9 ksi

Yield Strength (0.2% offset)

55 MPa8 ksi
50 MPa7.3 ksi
55 MPa8 ksi
80 MPa11.6 ksi

Elongation at Break

100%
120%
100%
20%

Compressive Strength

85 MPa12.3 ksi
60 MPa8.7 ksi
85 MPa12.3 ksi
100 MPa14.5 ksi

Compressive Modulus

2.4 GPa0.35 Msi
2.4 GPa0.35 Msi
3 GPa0.44 Msi

Flexural Strength

88 MPa12.8 ksi
70 MPa10.2 ksi
88 MPa12.8 ksi
120 MPa17.4 ksi

Flexural Modulus

2.4 GPa0.35 Msi
2.1 GPa0.3 Msi
2.4 GPa0.35 Msi
3.1 GPa0.45 Msi

Shear Strength

45 MPa6.5 ksi
45 MPa6.5 ksi
55 MPa8 ksi

Izod Impact, Notched

50 J/m0.94 ft·lbf/in
95 J/m1.8 ft·lbf/in
50 J/m0.94 ft·lbf/in
40 J/m0.75 ft·lbf/in

Hardness, Shore D

82 Shore D
78 Shore D
82 Shore D
85 Shore D

Hardness, Rockwell M

70 HRM
75 HRM
94 HRM

Hardness, Rockwell R

118 HRR
115 HRR
118 HRR
120 HRR

Fracture Toughness (K_IC)

2.5 MPa·√m2.3 ksi·√in
4 MPa·√m3.6 ksi·√in

Same in both: Poisson's Ratio 0.4

Physical

Density and transition temperatures.

Density

1.31 g/cm³0.05 lb/in³
1.27 g/cm³0.05 lb/in³
1.31 g/cm³0.05 lb/in³
1.39 g/cm³0.05 lb/in³

Melting Temperature (Tm)

225°C437 °F
225°C437 °F
255°C491 °F

Glass Transition (Tg)

50°C122 °F
80°C176 °F
55°C131 °F
79°C174 °F

Water Absorption (24 h)

0.08%
0.13%
0.09%
0.11%

Water Absorption (Saturation)

0.45%
0.5%
0.45%
0.5%

Refractive Index

1.58
1.57
1.575

Light Transmission

89%
88%

Thermal

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

Thermal Conductivity

0.23 W/m·K0.13 BTU/hr·ft·°F
0.2 W/m·K0.12 BTU/hr·ft·°F
0.25 W/m·K0.14 BTU/hr·ft·°F
0.25 W/m·K0.14 BTU/hr·ft·°F

Specific Heat Capacity

1,500 J/kg·K0.36 BTU/lb·°F
1,200 J/kg·K0.29 BTU/lb·°F
1,500 J/kg·K0.36 BTU/lb·°F
1,150 J/kg·K0.27 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

80 µm/m·K44.4 µin/in·°F
68 µm/m·K37.8 µin/in·°F
80 µm/m·K44.4 µin/in·°F
65 µm/m·K36.1 µin/in·°F

Max Service Temperature (continuous)

120°C248 °F
63°C145 °F
110°C230 °F
100°C212 °F

Min Service Temperature

-40°C-40 °F
-40°C-40 °F
-40°C-40 °F
-20°C-4 °F

Heat Deflection Temp. @ 0.45 MPa

150°C302 °F
70°C158 °F
155°C311 °F
115°C239 °F

Heat Deflection Temp. @ 1.8 MPa

60°C140 °F
64°C147 °F
60°C140 °F
80°C176 °F

Vicat Softening Point (B50)

178°C352 °F
82°C180 °F
178°C352 °F
180°C356 °F

Limiting Oxygen Index

21%
23%
21%
22%

Max Service Temperature (short-term)

160°C320 °F
75°C167 °F
160°C320 °F
150°C302 °F

Electrical

Conductivity and insulation.

Dielectric Strength

22 kV/mm559 V/mil
16 kV/mm406 V/mil
23 kV/mm584 V/mil
22 kV/mm559 V/mil

Dielectric Constant (1 MHz)

3.1
2.8
3.1
3.2

Dissipation Factor (1 MHz)

0.018
0.02
0.02
0.018

Surface Resistivity

1×10¹⁵ Ω
1×10¹⁶ Ω
1×10¹⁵ Ω
1×10¹⁵ Ω

Comparative Tracking Index (CTI)

600 V
600 V
600 V

Same in both: Electrical Resistivity 1×10¹⁴ Ω·m3.94×10²¹ µΩ·in · Volume Resistivity 1×10¹⁶ Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

78 / 100
85 / 100
82 / 100
70 / 100

UV / Weathering Resistance

35 / 100
45 / 100
35 / 100
30 / 100

Manufacturability

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

Machinability

68 / 100
65 / 100
68 / 100
78 / 100

Weldability

70 / 100
80 / 100
70 / 100
45 / 100

Formability (cold)

30 / 100
88 / 100
20 / 100
50 / 100

Polishability

45 / 100
72 / 100
55 / 100
60 / 100

Mold Shrinkage

1.7%
0.35%
1.8%
2%

Melt Flow Rate

25 g/10 min
25 g/10 min

Processing Melt Temperature (typ.)

255°C491 °F
245°C473 °F
250°C482 °F
280°C536 °F

Mold Temperature (typ.)

70°C158 °F
25°C77 °F
70°C158 °F
135°C275 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

95 MJ/kg40,843 BTU/lb
84 MJ/kg36,114 BTU/lb
105 MJ/kg45,142 BTU/lb
82 MJ/kg35,254 BTU/lb

Embodied Carbon (primary production)

4.4 kg CO₂/kg
3.2 kg CO₂/kg
5 kg CO₂/kg
2.8 kg CO₂/kg

Embodied Water

250 L/kg30 gal/lb
210 L/kg25.2 gal/lb
250 L/kg30 gal/lb
120 L/kg14.4 gal/lb

Typical Recycled Content

5%
0%
5%
25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

42 kN·m/kg
39 kN·m/kg
42 kN·m/kg
59 kN·m/kg

Specific Stiffness (E / density)

2 MN·m/kg
1.7 MN·m/kg
2 MN·m/kg
2.2 MN·m/kg

Modulus of Resilience

582 kJ/m³
595 kJ/m³
582 kJ/m³
1,032 kJ/m³

Thermal Diffusivity

0.1 mm²/s
0.1 mm²/s
0.1 mm²/s
0.2 mm²/s

Same in both: 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 scalePETGPBTPETPTMT

Manufacturing and finishing

CapabilityPTMTPETGPBTPET
CNC machiningYesYes
Sheet metalYesYes
Injection moldingYesYesYes
3D printingYes
Default conditionUnfilledUnfilledUnfilled
Relative cost$$ Standard$ Budget$$ Standard$$ Standard
Min. machined wall0.5 mm0.5 mm
Best machined surfaceRa 0.8 µmRa 0.8 µm
Chrome Plating (Plastic)YesYesYes
Conductive CoatingYes
Dyeing (Nylon)Yes
EMI Shielding CoatingYesYesYes
PaintingYesYes
Primer CoatingYes
Soft Touch CoatingYesYesYes
Spray PaintingYesYesYes
Tinted CoatingYes
UV CoatingYesYesYes
Vacuum MetallizationYes
Waterproof CoatingYes

Ready to make it?

Upload a CAD file and FabDigit prices the part in PTMT and PETG 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.