PEEK Injection Molding
We mold PEEK (and compatible grades) for functional, structural and aesthetic parts — from low-volume bridge production to high-volume runs.
PEEK: The Ultra-High-Performance Thermoplastic
Property data per FirstMold's PEEK page (https://firstmold.com/peek-injection-molding/); MOLDITQUICK runs PEEK on all-electric Sodick machines with closed-loop temperature control.
Continuous service at 260 °C with short-term tolerance to 300 °C — the highest of melt-processable thermoplastics.
Tensile strength 90–100 MPa and about 4× the wear resistance of PTFE.
Low shrinkage (0.1–0.5 %) with a thermal expansion coefficient close to aluminum — dimensionally stable across temperature.
Biocompatible — FDA-certified grades used in long-term implants without rejection.
Cryogenic resistance — retains strength down to −60 °C.
Chemical resistance — survives strong acids (except concentrated H₂SO₄) and organic solvents.
Radiation resistance — PEEK tolerates gamma sterilization and nuclear environments, useful in medical and aerospace.
Low outgassing — suitable for semiconductor vacuum and cleanroom applications.
PEEK Processing Parameters We Control
Windows per FirstMold's PEEK processing data (https://firstmold.com/peek-injection-molding/); melt stability is the difference between a good and a scrap PEEK part.
| Parameter | Recommended Range | Why It Matters |
|---|---|---|
| Barrel temperature | 340–400 °C (FirstMold: 360–400 °C) | Melt must stay hot and stable; deviations of even ~2 °C can cause crystallization and embrittlement. |
| Mold temperature | 150–200 °C (typical 160–180 °C) | Hot molds prevent cold slugs and promote crystallinity for maximum strength. |
| Mold shrinkage | 0.1–0.5 % | Very low and predictable — close to metal-like dimensional stability. |
| Melt stability | ±1.5 °C closed-loop control | FirstMold reports first-shot success above 92 % on thin-wall PEEK with all-electric machines. |
| Drying | 150 °C, ~3 h | PEEK absorbs little moisture, but surface moisture must be driven off before molding. |
Cost & Process Realities of PEEK
What makes PEEK expensive — and how we keep the cost under control (https://firstmold.com/peek-injection-molding/).
Material cost is high
PEEK resin costs multiples of engineering plastics — part design, gating and scrap control decide the bill.
- Net-shape molding
- Minimal runner waste
- Regrind strategy with supplier approval
Tooling must run hot
Molds run at 150–200 °C with hot runners and hardened steel; cold slugs destroy quality.
- Hot runner systems
- High-temperature mold steel
- Modular PEEK-dedicated designs
Processing demands precision
A 2 °C deviation can crystallize and embrittle an entire batch — machines must hold ±1.5 °C.
- All-electric presses
- Closed-loop temperature
- First-shot success 92 %+
Alternatives when budget bites
PEKK needs only 10–15 °C more than PEEK; PEI (Ultem) covers continuous use to 170 °C at medium cost.
- PEKK upgrade path
- PEI for sub-170 °C service
- PPS for heat and chemical balance
Surface & tolerance control
PEEK parts hold tight tolerances with 0.1–0.5 % shrinkage; we verify with first-article measurement.
- 0.1–0.5 % shrinkage
- First-article verification
- GD&T reporting
PEEK vs PEI: Which High-Temperature Resin Fits?
Where PEEK Injection Molding Pays
Aerospace
Satellite components, oil seals and high-load bushings that must keep properties above 200 °C.
Medical
Surgical instruments, minimally invasive tools with walls under 0.1 mm, and FDA-certified implantable components.
Semiconductor
Wafer carriers, chamber components and high-temperature process hardware.
Oil & gas
Deep-well exploration seals rated to 150 MPa pressure.
Robotics & industrial
Joint and wear components where creep resistance and self-lubrication beat metal.
Automotive & motorsport
High-temperature seals, thrust washers and sensor components under the hood.
Downhole & subsea
Insulators, connectors and seals that face high pressure and aggressive fluids.
PEEK Design Rules We Enforce
- ✓Design for a hot mold — PEEK needs 150–200 °C mold temperature; plan cooling and draft accordingly.
- ✓Keep walls as uniform as possible; ultra-thin walls (under 0.1 mm) are possible only with precisely controlled melt.
- ✓Account for very low shrinkage (0.1–0.5 %) — cavity sizing follows PEEK's own rules, not PP's.
- ✓Avoid cold slugs — use hot runners and full hot-drop systems on critical areas.
- ✓Validate crystallinity — the process window must hold melt temperature steady (we hold ±1.5 °C) so parts do not embrittle.
- ✓Confirm chemical exposure early — PEEK survives most solvents, but concentrated H₂SO₄ is out.
- ✓Specify the correct PEEK family — unfilled, glass- or carbon-fiber-reinforced grades have different wear, stiffness and cost profiles.
PEEK Injection Molding FAQ
- ✓Q: What temperature can PEEK parts take? A: Continuous service to 260 °C and short-term peaks to 300 °C — the best of any melt-processable plastic.
- ✓Q: Is PEEK biocompatible? A: Yes — FDA-certified grades are used in long-term implants; we run medical programs under ISO13485.
- ✓Q: Why is PEEK molding so hard? A: The melt window is high and narrow — a ~2 °C deviation can embrittle parts. We mold on all-electric Sodick machines holding ±1.5 °C.
- ✓Q: Can thin-wall PEEK parts be molded? A: Yes — we produce walls under 0.1 mm for surgical instruments with high first-shot success.
- ✓Q: What lead time for PEEK parts? A: Low-volume 7–12 days, production 25–30 days — DFM and in-house tooling keep the program on schedule.
- ✓Q: Does PEEK outgas in vacuum? A: Very little — PEEK is used in semiconductor vacuum chambers and aerospace where outgassing must be minimal.
- ✓Q: Can PEEK be sterilized? A: Yes — steam, EtO and gamma sterilization are all compatible with PEEK.
- ✓Q: What about PEEK regrind? A: Regrind is limited and supplier-approved — the high melt temperature makes repeated reprocessing risky.
Related Capabilities
Explore the full range of MOLDITQUICK manufacturing services.