PEI
also Sabic ULTEM, Ultem
PEI (polyetherimide, sold as Ultem and Extem) is an amorphous high-performance engineering thermoplastic with a Tg of about 217 °C, inherent UL94 V-0 flame retardance and low smoke (LOI ≈47 %), stable dielectric properties and good dimensional stability.
Values for the Unfilled (1000) condition
PEI grades and fills
PEI is supplied in 13 conditions, soft to hard. Unfilled (1000) is the default FabDigit quotes; the values on this page are for it.
- Standard (FAA Approved)
- As Printed
- 9085
- Lubricated
- ESD
- Unfilled (1000)
- 1010
- GF10
- GF20
- GF30
- GF30 (2300)
- GF40
- CF30
Compare all 13 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Certified FST/aerospace-qualified material lot | Specify when documentation (FAR 25.853 flammability/smoke/toxicity, lot traceability) is required for aircraft cabin parts. | 69 | 72 | 20 | 85 Shore D |
FDM/FFF printed PEI (9085/1010), layer-direction properties | Use for design allowables of FDM-printed PEI parts: expect 60–80% of molded strength in-plane and much lower Z-axis strength. | 69 | 5.8 | ||
ULTEM 9085 | Pick for aircraft interior parts and FDM filament where FAR 25.853 heat-release/smoke compliance and better toughness/flow matter more than peak Tg. | 72 | 30 | ||
PTFE/graphite internally lubricated bearing grade (e.g. ULTEM 4000 series) | Select for unlubricated sliding parts (bushings, wear pads, valve seats) needing low friction at 150–170 °C. | 88 | 90 | 8 | 86 Shore D |
ESD / static-dissipative PEI compound | Use for wafer/electronics handling tooling where surface resistivity must sit in the 1e4–1e9 Ω dissipative window at high temperature. | 92 | 95 | 4 | 88 Shore D |
Unfilled (1000)Default Natural transparent amber injection/extrusion grade | Default choice for transparent, tough, high-Tg parts and stock shapes where isotropic properties and machinability matter. | 105 | 60 | 109 HRM | |
ULTEM 1010 | Choose for thin-wall/complex moldings, food-contact and biocompatible applications, and high-temperature FDM (Tg ≈ 217 °C, best flow of unfilled PEI). | 105 | 35 | ||
10% glass fiber reinforced | Lightly reinforced option when moderate stiffness gain and reduced shrinkage are needed but some ductility must be retained. | 120 | 6 | 110 HRM | |
20% glass fiber reinforced | Balanced stiffness/toughness reinforcement for structural brackets and connectors at elevated temperature. | 145 | 3.5 | ||
30% glass fiber reinforced | Standard high-stiffness structural PEI: use where load, creep resistance and low CTE dominate and surface finish/ductility can be sacrificed. | 165 | 3 | 114 HRM | |
ULTEM 2300, 30% glass filled SABIC grade | The benchmark commercial 30% GF PEI for machined stock shapes, semiconductor fixtures and high-load electrical parts. | 169 | 3 | 114 HRM | |
40% glass fiber reinforced | Maximum stiffness and lowest CTE PEI compound for metal-replacement structures; brittle and abrasive to tooling. | 190 | 2 | ||
30% carbon fiber reinforced PEI | Choose for maximum specific stiffness, low CTE and static-dissipative structural parts (semiconductor handling, aerospace fixtures). | 200 | 1.8 |
Supply forms, finishes and certifications
Ways PEI is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Medical | Biocompatible / sterilizable healthcare grade | Certification |
UnfilledDefault | Generic natural PEI resin / stock shape | Standard supply |
What is PEI?
PEI (polyetherimide, sold as Ultem and Extem) is an amorphous high-performance engineering thermoplastic with a Tg of about 217 °C, inherent UL94 V-0 flame retardance and low smoke (LOI ≈47 %), stable dielectric properties and good dimensional stability. Unfilled stock is 1.27 g/cm³ with 105 MPa tensile strength, 60 % elongation and 3.2 GPa modulus, supplied as transparent amber shapes, injection grades, GF10–GF40 and CF30 compounds and FDM filament (9085, 1010), and it withstands steam and gamma sterilisation. Limits are poor resistance to chlorinated solvents and strong alkalis, notch sensitivity and stress cracking, 340–400 °C processing temperatures and high price; PEEK is the step up when continuous service above Tg is required. PEI has a density of 1.27 g/cm³ (0.0459 lb/in³), heavier than 67% of polymer grades. Its glass-transition temperature is 217°C (423 °F). PEI has a yield strength of 105 MPa (15.2 ksi) and a tensile strength of 105 MPa (15.2 ksi) — stronger than 97% of polymer grades. Elongation at break is 60% and the elastic modulus is 3.2 GPa (0.464 Msi).
What is PEI used for?
- Aircraft interior panels and ducting
- Electrical connectors and insulators
- Sterilisable medical instrument handles and trays
- Semiconductor wafer carriers and test fixtures
- High-temperature fluid fittings and valve bodies
- Burn-in and test sockets
- Transparent sight glasses and lenses
Advantages
- High strength — 105 MPa (15.2 ksi), better than 97% of polymer grades
- High service temperature — 170°C (338 °F), better than 83% of polymer grades
- Stiff — 3.2 GPa (0.464 Msi), better than 77% of polymer grades
- Polishes to a fine finish — 70/100, better than 77% of polymer grades
Limitations
- High embodied carbon — 9 kg CO₂/kg, worse than 88% of polymer grades
PEI properties
Typical room-temperature values for PEI-Unfilled (1000); bars are the position among polymer grades.
Physical6
PEI has a density of 1.27 g/cm³ (0.0459 lb/in³), heavier than 67% of polymer grades. Its glass-transition temperature is 217°C (423 °F).
Mechanical17
PEI has a yield strength of 105 MPa (15.2 ksi) and a tensile strength of 105 MPa (15.2 ksi) — stronger than 97% of polymer grades. Elongation at break is 60% and the elastic modulus is 3.2 GPa (0.464 Msi).
Thermal11
PEI is rated for continuous service to 170°C (338 °F). It conducts heat at 0.22 W/m·K (0.127 BTU/hr·ft·°F), better than 60% of polymer grades. Thermal expansion is 55 µm/m·K (30.6 µin/in·°F).
Electrical7
PEI is an electrical insulator with a dielectric strength of 33 kV/mm (838.2 V/mil) and a resistivity of 1×10¹⁵ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 65% of polymer grades. UV resistance is fair.
Sustainability4
Producing a kilogram of PEI takes about 230 MJ of energy and emits 9 kg of CO₂ — more than 91% of polymer grades. Typical recycled content is 0%.
Manufacturability8
PEI's machinability is good (65/100, better than 66% of polymer grades); weldability good (60/100); formability fair (45/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. PEI is highlighted; hover a dot for its name, or open the interactive family chart.
Working with PEI
Is PEI easy to machine?
Machines cleanly with sharp carbide tools, high speed and light feeds; use air or water-soluble coolant (avoid chlorinated fluids), anneal 150–200 °C before finish cuts to prevent stress cracking, and keep generous radii because PEI is notch sensitive.
Can PEI be welded?
Joins by ultrasonic, hot-plate, spin and laser welding; solvent bonding is discouraged (stress cracking) — use epoxy or high-temperature adhesives with plasma/abrasive surface prep.
Can PEI be formed, bent or molded?
Dry to <0.02% moisture (150 °C, 4+ h), mold at 340–400 °C melt with 135–175 °C tools and hot-tip/hardened gates for glass grades; thermoformable and extrudable above Tg with high-temperature tooling.
Manufacturability
The process limits FabDigit's quote engine applies to PEI. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Better65 / 100 |
|---|---|
| ISO material group | N.8 |
| Cutting speed (rough / finish) | 400 / 500 m/min |
| Minimum wall | 0.5 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 10× diameter |
| Best surface (machined / polished) | Ra 0.8 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Not Recommend45 / 100 |
|---|---|
| Weldability | Excellent60 / 100 |
Injection molding
| Mold shrinkage | 1.5 – 2.2 % |
|---|---|
| Wall thickness | 1 – 3.5 mm |
| Recommended draft | 1.5 ° |
| Pre-drying | 80 °C for 4 h |
| UV resistance | Fair |
3D printing
| Technologies | FDM |
|---|---|
| Layer height | 50 – 300 µmdefault 100 µm |
| Minimum wall / feature | 1 / 0.5 mm |
| Build envelope | 300 × 300 × 380 mm |
| Supports | Yes |
| Anisotropy | Moderate |
PEI 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 |
|---|---|---|
| m-phenylenediamine (MPD) unitdiamine comonomer of standard PEI (ULTEM 1000/1010) | — | |
| polycarbonate/siloxane or alternative copresent only in copolymer grades such as ULTEM 9085 | — | |
| glass fiber0 for unfilled; 10/20/30/40 wt% in 2100/2200/2300/2400 series | 0 – 40 | 0 |
| bisphenol A dianhydride (BPADA) unitether-imide backbone from BPADA condensation | balance |
What surface finishes work on PEI?
Takes pad printing, laser marking, vacuum metallization and EMI shielding coatings; can be polished to clear amber; primers required for durable paint adhesion and no anodizing/plating without conductive pretreatment.
Surface treatments FabDigit runs on polymer parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Coating
Injection Molding Coating
Organic Coating
Metallization / Functional
Coloring
Equivalent designations
Standards and trade names that resolve to PEI in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Sabic ULTEMUltemUltem PEIExtem
- Also called
- Polyetherimide
How much does PEI cost?
PEI is a specialty-cost polymer ($$$$$), pricier than about 99% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
PEI — frequently asked
What is PEI used for?
PEI is typically used for aircraft interior panels and ducting, electrical connectors and insulators, sterilisable medical instrument handles and trays, semiconductor wafer carriers and test fixtures, high-temperature fluid fittings and valve bodies and burn-in and test sockets. In short: high-heat aerospace standard.
What is the yield strength of PEI?
PEI has a typical yield strength of 105 MPa (15.2 ksi) and a tensile strength of 105 MPa (15.2 ksi) — stronger than 97% of polymer grades. Strength varies by condition: see the 13 listed tempers.
Is PEI easy to machine?
Reasonably — machinability is rated good (65/100, better than 66% of polymer grades). Machines cleanly with sharp carbide tools, high speed and light feeds; use air or water-soluble coolant (avoid chlorinated fluids), anneal 150–200 °C before finish cuts to prevent stress cracking, and keep generous radii because PEI is notch sensitive.
Can PEI be welded?
Yes — weldability is rated good (60/100). Joins by ultrasonic, hot-plate, spin and laser welding; solvent bonding is discouraged (stress cracking) — use epoxy or high-temperature adhesives with plasma/abrasive surface prep.
What surface finishes work on PEI?
Takes pad printing, laser marking, vacuum metallization and EMI shielding coatings; can be polished to clear amber; primers required for durable paint adhesion and no anodizing/plating without conductive pretreatment.
Can PEI be formed, bent or molded?
Dry to <0.02% moisture (150 °C, 4+ h), mold at 340–400 °C melt with 135–175 °C tools and hot-tip/hardened gates for glass grades; thermoformable and extrudable above Tg with high-temperature tooling.
What is the maximum service temperature of PEI?
PEI is rated for continuous use to about 170°C (338 °F), and briefly to 200°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between PEI Unfilled (1000) and PEI ESD?
Unfilled (1000) is the default condition — default choice for transparent, tough, high-Tg parts and stock shapes where isotropic properties and machinability matter. ESD: use for wafer/electronics handling tooling where surface resistivity must sit in the 1e4–1e9 Ω dissipative window at high temperature. Yield strength is 105 MPa in Unfilled (1000) versus 92 MPa in ESD.
How much does PEI cost?
PEI is a specialty-cost polymer ($$$$$), pricier than about 99% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in PEI?
Yes — PEI is available for CNC machining, sheet metal, injection molding and 3D printing with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ULTEM 1000 / 1010 / 2300 / 9085 resin datasheets — SABIC Specialty Polymers (2023)
- TECAPEI natural / GF30 stock shape datasheets — Ensinger (2023)
- ULTEM 9085 / 1010 FDM material specification — Stratasys (2022)
- CAMPUS plastics multi-point data, polyetherimide — CWFG/CAMPUS (2024)
- ASTM D5205 Standard Classification System for Polyetherimide (PEI) Materials — ASTM (2020)
- Engineering Plastics Handbook / Plastics Design Library — high-temperature thermoplastics — McGraw-Hill / Elsevier (2006)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.