Typical PEEK
- Excellent chemical and wear resistance
- Highest heat capability in this pair
- Highest resin and processing cost
High performance comparison
PEEK vs Ultem (PEI): High Heat Thermoplastics Compared
Both survive elevated temperature. PEEK leads on chemical and wear extremes; Ultem balances heat with lower resin cost in many electrical applications.
High performance comparison
When standard engineering plastics stop
These resins justify cost only when testing proves standard grades fail.
Electrical and medical adjacent parts sometimes need PEI before jumping to PEEK.
PEEK appears when chemical, wear, and continuous heat stack together.
Resin choice
Typical versus Typical at a glance
Use this routing before you lock the BOM. NetProto molds both once the resin is specified on the quote.
Typical PEI (Ultem)
- Strong heat and flame performance for electrical housings
- Lower cost than PEEK in many gauges
- Amber natural color unless color matched
Decision table
Where each resin usually wins
Qualitative tradeoffs for molded parts. Confirm shrink, fill, and tooling details on the material guide.
| Factor | PEEK | PEI (Ultem) |
|---|---|---|
| Continuous heat | Very high | High |
| Chemicals | Very broad resistance | Good, application specific |
| Cost | Premium | High but below PEEK |
| Fill | Carbon and glass fills common on PEEK | Glass fill common on PEI |
Before you quote
Send this context with your CAD
The instant quote uses your material choice for fill, gate, and steel assumptions.
Continuous use temperature and peak events
Flame or dielectric requirements
Chemical exposure list
Acceptable natural color or pigment system
Material guides
Full property pages
These library pages carry datasheets, DFM notes, and quote checklists.
PEEK
Open the PEEK molding guide.
PEEKPEI (Ultem)
Open the PEI (Ultem) molding guide.
PEI (Ultem)Continue exploring
Related comparisons
Open a sibling guide or jump to the full material library.
Compare hub
All comparison guides.
Compare hubMaterials library
Deep guides per resin family.
Materials libraryPET vs PBT
Lower cost polyester pair.
PET vs PBTGlass filled vs unfilled
When fill is required for modulus.
Glass filled vs unfilledFAQ
Common questions
Do both need hot tooling?
High heat resins need mold temperature control aligned to supplier guidance. Confirm in DFM before tooling starts.
Next step
Quote both options with the same CAD
Upload once, switch resin in the quote flow, and compare piece price on the same tool. NetProto manufacturing is ISO 9001 certified.