PMI Foam Core (Rohacell) 71WF
Grade
also ROHACELL
Standard aerospace core density for 180 °C epoxy prepreg co-cure at up to 0.7 MPa.
Values for the 71WF condition
Other PMI Foam Core (Rohacell) grades and fills
PMI Foam Core (Rohacell) is listed in 14 conditions; see the grade overview at PMI Foam Core (Rohacell).
Compare all 14 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
32 kg/m³ fine-cell industrial grade | Lowest density; radome and lightweight non-structural cores where stiffness demand is low. | — | 1 | 3.5 | — |
52 kg/m³ fine-cell industrial grade | Most common general-purpose density for prepreg sandwich panels and antenna structures. | — | 2 | 3 | — |
52 kg/m³ high-temperature aerospace grade | Pick WF over IG when the part is autoclave co-cured at 180 °C / high pressure and qualified aerospace data are needed. | — | 2 | 4.5 | — |
High energy absorption / damage tolerant grade | Choose when impact damage tolerance and crush energy absorption matter more than peak stiffness (leading edges, crash structures). | — | 2 | 8 | — |
High-frequency / radome dielectric grade | Tightly controlled low dielectric constant and loss tangent for radomes and antenna sandwich panels. | — | 2 | 3.5 | — |
in-mould foamable (particle) grade | Foamed directly into complex 3D cavities for high-volume parts, avoiding block machining and scrap. | — | 2 | 3 | — |
Solution annealed | Use where FAR 25.853 heat-release, smoke and toxicity requirements apply (cabin interiors, ducts). | — | 2 | 3 | — |
71IG-FDefault 75 kg/m³ fine-cell industrial grade | Default workhorse density: good shear strength/weight balance for structural sandwich skins and sporting goods. | — | 2 | 3 | — |
71WFThis page 75 kg/m³ high-temperature aerospace grade | Standard aerospace core density for 180 °C epoxy prepreg co-cure at up to 0.7 MPa. | — | 2 | 4.5 | — |
110 kg/m³ fine-cell industrial grade | Higher density for locally loaded areas, inserts, hardpoints and thin skins with high pressure cure. | — | 4 | 3 | — |
110 kg/m³ high-temperature aerospace grade | For high-pressure autoclave cure and heavily loaded sandwich zones (helicopter blades, control surfaces). | — | 4 | 4.5 | — |
S / HT | For BMI/high-Tg epoxy cures and service above 180 °C where standard WF would creep or collapse. | — | 4 | 4.5 | — |
205 kg/m³ high-density aerospace grade | High-density core for local load introduction, bearing pads and high-pressure cure cycles. | — | 7 | 4.5 | — |
300 kg/m³ maximum-density grade | Densest PMI block; used as machinable structural filler/insert material replacing hardwood or syntactic. | — | 11 | 3.5 | — |
What is PMI Foam Core (Rohacell) 71WF?
PMI Foam Core (Rohacell) 71WF is PMI Foam Core (Rohacell) in the 71WF grade — standard aerospace core density for 180 °C epoxy prepreg co-cure at up to 0.7 MPa. PMI Foam Core (Rohacell) 71WF has a tensile strength of 2 MPa (0.319 ksi), weaker than 92% of composite grades. Elongation at break is 4.5% and the elastic modulus is 0.11 GPa (0.0152 Msi). PMI Foam Core (Rohacell) 71WF has a density of 0.08 g/cm³ (0.0027 lb/in³), lighter than 91% of composite grades. Its glass-transition temperature is 210°C (410 °F). 71IG-F is the default condition FabDigit quotes; 71WF is available on request or by drawing note.
Advantages
- Lightweight — 0.08 g/cm³ (0.0027 lb/in³), better than 91% of composite grades
- Easy to machine — 85/100, better than 90% of composite grades
- Ductile — tolerates forming and impact — 4.5%, better than 85% of composite grades
Limitations
- Poor heat conductor — 0.03 W/m·K (0.0191 BTU/hr·ft·°F), worse than 96% of composite grades
- Low stiffness — 0.11 GPa (0.0152 Msi), worse than 91% of composite grades
- Degrades in UV without stabilisers — 25/100, worse than 86% of composite grades
PMI Foam Core (Rohacell) 71WF properties
Typical room-temperature values for PMI Foam Core (Rohacell) 71WF; 10 are specific to this condition. Other listed values are PMI Foam Core (Rohacell) reference data and may not represent this condition. Bars are the position among composite grades.
Physical2
PMI Foam Core (Rohacell) 71WF has a density of 0.08 g/cm³ (0.0027 lb/in³), lighter than 91% of composite grades. Its glass-transition temperature is 210°C (410 °F).
Mechanical8
PMI Foam Core (Rohacell) 71WF has a tensile strength of 2 MPa (0.319 ksi), weaker than 92% of composite grades. Elongation at break is 4.5% and the elastic modulus is 0.11 GPa (0.0152 Msi).
Thermal7
PMI Foam Core (Rohacell) 71WF is rated for continuous service to 180°C (356 °F). It conducts heat at 0.03 W/m·K (0.0191 BTU/hr·ft·°F), worse than 96% of composite grades. Thermal expansion is 35 µm/m·K (19.4 µin/in·°F).
Electrical2
Chemical & Environmental2
UV resistance is poor.
Sustainability3
Producing a kilogram of PMI Foam Core (Rohacell) 71WF takes about 130 MJ of energy and emits 6.5 kg of CO₂ — less than 56% of composite grades. Typical recycled content is 0%.
Manufacturability1
PMI Foam Core (Rohacell) 71WF's machinability is excellent (85/100, better than 90% of composite grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with PMI Foam Core (Rohacell) 71WF
Is PMI Foam Core (Rohacell) easy to machine?
CNC mills, saws, hot-wire and abrasive-waterjet cut easily with sharp uncoated tools and vacuum hold-down; use dust extraction and avoid melting from tool rubbing.
Can PMI Foam Core (Rohacell) be welded?
Not weldable; blocks are joined by epoxy/film-adhesive bonding or thermal splicing of billets before machining.
Can PMI Foam Core (Rohacell) be formed, bent or molded?
Thermoformable above ~180 °C over a tool for curved skins; must be oven-dried (e.g. 100–130 °C) before autoclave co-cure to prevent blistering and skin disbonds.
What surface finishes work on PMI Foam Core (Rohacell)?
Cell faces are open after machining — seal with film adhesive, surfacing film or low-density filler paste before painting or resin infusion.
PMI Foam Core (Rohacell) chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| methacrylic acid (units)co-monomer, imidized during foaming | 45 – 55 | 50 |
| methacrylonitrile (units)co-monomer; ring-closes to methacrylimide | 45 – 55 | 50 |
| blowing agent / additivesalcohol/formamide type blowing agent, FR additives in A grades | 0 – 5 | 2 |
PMI Foam Core (Rohacell) 71WF — frequently asked
What is PMI Foam Core (Rohacell) 71WF used for?
PMI Foam Core (Rohacell) 71WF is typically used for aircraft radomes and control surfaces, formula 1 composite panels, satellite structures and medical imaging tables. In short: highest-temperature structural foam; autoclave co-curable core; best specific strength foam.
What is the tensile strength of PMI Foam Core (Rohacell) 71WF?
PMI Foam Core (Rohacell) 71WF has a typical tensile strength of 2 MPa (0.319 ksi) — weaker than 92% of composite grades. Strength varies by condition: see the 14 listed tempers.
Is PMI Foam Core (Rohacell) 71WF easy to machine?
Yes — machinability is rated excellent (85/100, better than 90% of composite grades). CNC mills, saws, hot-wire and abrasive-waterjet cut easily with sharp uncoated tools and vacuum hold-down; use dust extraction and avoid melting from tool rubbing.
Can PMI Foam Core (Rohacell) 71WF be welded?
Not weldable; blocks are joined by epoxy/film-adhesive bonding or thermal splicing of billets before machining.
What surface finishes work on PMI Foam Core (Rohacell) 71WF?
Cell faces are open after machining — seal with film adhesive, surfacing film or low-density filler paste before painting or resin infusion.
Can PMI Foam Core (Rohacell) 71WF be formed, bent or molded?
Thermoformable above ~180 °C over a tool for curved skins; must be oven-dried (e.g. 100–130 °C) before autoclave co-cure to prevent blistering and skin disbonds.
What is the maximum service temperature of PMI Foam Core (Rohacell) 71WF?
PMI Foam Core (Rohacell) 71WF is rated for continuous use to about 180°C (356 °F), and briefly to 205°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ROHACELL IG / IG-F product information — Evonik Industries (2023)
- ROHACELL WF product information — Evonik Industries (2023)
- ROHACELL HERO / RIST / Triple F technical brochures — Evonik Industries (2022)
- ASTM C365 / C273 / D1621 — sandwich core compressive and shear test methods — ASTM (2022)
- ASM Handbook Vol. 21: Composites — sandwich core materials — ASM International (2001)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.