HDPE vs LLDPE
Polymer · grade comparison
HDPE and LLDPE are both polymer grades. HDPE is the stronger of the two: yield strength 26 MPa (3.77 ksi) against 11 MPa (1.6 ksi) for LLDPE, about 136% more; tensile strength follows at 28 MPa (4.06 ksi) vs 25 MPa (3.63 ksi). In exchange, LLDPE is the more ductile: elongation 700% versus 600% for HDPE, and HDPE is harder (65 Shore D vs 50 Shore D). LLDPE is lighter (0.92 g/cm³ vs 0.96 g/cm³ for HDPE) and HDPE is stiffer (1.1 GPa vs 0.25 GPa). On the shop floor, HDPE machines more easily (very good vs good).
HDPEChoose it when strength drives the design, or when the part is machined in volume.
LLDPEChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
HDPE vs LLDPE: 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 R
Hardness, Shore A
Physical
Density and transition temperatures.
Density
Melting Temperature (Tm)
Water Absorption (Saturation)
Refractive Index
Same in both: Glass Transition (Tg) -110°C-166 °F · Water Absorption (24 h) 0.01%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Min Service Temperature
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: Max Service Temperature (continuous) 80°C176 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Strength
Dielectric Constant (1 MHz)
Volume Resistivity
Same in both: Dissipation Factor (1 MHz) 3×10⁻⁴ · Surface Resistivity 1×10¹⁵ Ω · Comparative Tracking Index (CTI) 600 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Corrosion Resistance 90 / 100 · UV / Weathering Resistance 25 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Melt Flow Rate
Processing Melt Temperature (typ.)
Same in both: Polishability 30 / 100 · Mold Shrinkage 2% · Mold Temperature (typ.) 40°C104 °F
Sustainability
Primary-production footprint per kilogram.
Embodied Water
Same in both: Embodied Energy (primary production) 78 MJ/kg33,534 BTU/lb · Embodied Carbon (primary production) 2 kg CO₂/kg · Typical Recycled Content 10%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
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.
Manufacturing and finishing
| Capability | HDPE | LLDPE |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| Injection molding | Yes | — |
| Default condition | FDA Compliant | — |
| Relative cost | $ Budget | $ Budget |
| Min. machined wall | 0.5 mm | — |
| Best machined surface | Ra 0.8 µm | — |
| Chrome Plating (Plastic) | Yes | — |
| EMI Shielding Coating | Yes | — |
| Painting | Yes | — |
| Soft Touch Coating | Yes | — |
| Spray Painting | Yes | — |
| UV Coating | Yes | — |
HDPE vs LLDPE — frequently asked
Is HDPE stronger than LLDPE?
Yes. HDPE has a typical yield strength of 26 MPa (3.77 ksi) against 11 MPa (1.6 ksi) for LLDPE — about 136% more. Tensile strength is 28 MPa (4.06 ksi) vs 25 MPa (3.63 ksi).
Which is cheaper, HDPE or LLDPE?
Both sit in the same relative cost tier ($, budget); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, HDPE or LLDPE?
HDPE. Its machinability rates very good (75/100) against good (55/100) for LLDPE; for welding the order is HDPE first (excellent, 95/100) then LLDPE (excellent, 90/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in HDPE and LLDPE 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.