PEI / ULTEM, PEEK, and PEKK for FDM / FFF 3D Printing

PEI, commonly sold under the ULTEM name, along with PEEK and PEKK, belongs to the high-performance polymer category. These materials are used when the application requires high heat resistance, mechanical performance, chemical resistance, flame/smoke behavior, or advanced engineering properties. High-performance filament guides commonly group PEI/ULTEM, PEEK, PEKK, PPSU, and related materials together as advanced polymers requiring more capable printing systems.

PEI / ULTEM

PEI is an amorphous high-performance polymer. ULTEM is a well-known branded PEI material. It is often discussed for aerospace, transportation, electrical, and high-performance industrial applications.

PEI may be useful for:

• Heat-resistant parts
• Flame-resistant applications
• Electrical components
• Aerospace support parts
• High-performance tooling
• Functional prototypes
• Parts needing better dimensional stability than commodity polymers

PEEK

PEEK is a semi-crystalline high-performance polymer. It is known for high temperature capability, chemical resistance, mechanical strength, and demanding engineering applications.

PEEK may be useful for:

• High-temperature components
• Chemically resistant parts
• Advanced industrial prototypes
• Medical and aerospace development applications
• Wear-related components
• Metal-replacement development studies

PEEK is difficult to print well. It generally requires high nozzle temperatures, high bed temperatures, high chamber temperatures, dry material, and strong process control.

PEKK

PEKK is related to PEEK but can be somewhat more process-adjustable depending on grade and crystallinity. It is used in high-performance applications where heat, chemistry, and strength matter.

PEKK may be useful for:

• Advanced aerospace and industrial parts
• High-temperature tooling
• Chemical-resistant components
• Functional development parts
• Metal-replacement applications
• High-performance prototypes

Challenges With Ether Ketones and PEI

These materials are not for ordinary desktop printing.

Challenges include:

• High nozzle temperature
• High bed temperature
• Heated chamber requirement
• Moisture control
• Warping and crystallization behavior
• Layer adhesion challenges
• Material cost
• Printer cost
• Need for post-processing or annealing in some cases
• Application-specific validation

JaegerTech View

PEI, PEEK, and PEKK are serious materials for serious applications. We would not recommend them just because they sound impressive. They should be used when the environment, performance requirement, or customer specification justifies the cost and process requirements.