FFKM vs FKM
Polymer · grade comparison
FFKM and FKM are both polymer grades, both corrosion resistant plastic. FFKM is the stronger of the two: tensile strength 17 MPa (2.47 ksi) against 12 MPa (1.74 ksi) for FKM, about 42% more. In exchange, FKM is the more ductile: elongation 200% versus 140% for FFKM. FKM is lighter (1.82 g/cm³ vs 2 g/cm³ for FFKM) and FFKM is stiffer (0.01 GPa vs 0.01 GPa).
FFKMChoose it when strength drives the design, or when the part sees heat.
FKMChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
FFKM vs FKM: 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
Tensile Strength (Ultimate)
Elongation at Break
Shear Strength
Tear Strength
Same in both: Poisson's Ratio 0.49 · Hardness, Shore A 75 Shore A · Compression Set (22 h, 70 °C) 12%
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Water Absorption (24 h)
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Limiting Oxygen Index
Max Service Temperature (short-term)
Same in both: Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Strength
Dielectric Constant (1 MHz)
Volume Resistivity
Dissipation Factor (1 MHz)
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: UV / Weathering Resistance 95 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Mold Shrinkage
Mold Temperature (typ.)
Processing Melt Temperature (typ.)
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 0%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Thermal Shock Resistance Index
Same in both: Specific Stiffness (E / density) 0 MN·m/kg · Thermal Diffusivity 0.1 mm²/s
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 | FFKM | FKM |
|---|---|---|
| Default condition | Semiconductor Grade | Standard |
| Relative cost | $$ Standard | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both are offered for Injection molding. Both take the same 5 finishes: Chrome Plating (Plastic), EMI Shielding Coating, Soft Touch Coating, Spray Painting, UV Coating.
FFKM vs FKM — frequently asked
Is FFKM stronger than FKM?
Yes. FFKM has a typical tensile strength of 17 MPa (2.47 ksi) against 12 MPa (1.74 ksi) for FKM — about 42% more.
Which is cheaper, FFKM or FKM?
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 is easier to machine, FFKM or FKM?
FKM, by a small margin. Both rate poor for machinability — 25/100 against 20/100 for FFKM.
Ready to make it?
Upload a CAD file and FabDigit prices the part in FFKM and FKM 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.