PEKK

PEKK FILAMENT: High-Performance Thermoplastic related to PEEK

A Guide to PEKK Filament for FDM 3D Printing

Polyetherketoneketone (PEKK) filament is a high-performance thermoplastic closely related to PEEK but with unique characteristics that set it apart. Known for its exceptional strength, thermal stability, and chemical resistance, PEKK is a premium material used in demanding applications across various industries, including aerospace, automotive, and medical sectors.

This guide will explore what PEKK filament is, its physical properties, applications, and the advantages and disadvantages of using it in 3D printing.

What is PEKK Filament?

PEKK, or Polyetherketoneketone, is a semi-crystalline thermoplastic belonging to the polyaryletherketone (PAEK) family, much like PEEK. It is characterized by its exceptional thermal and mechanical properties, making it suitable for applications that require high-performance materials.

Compared to PEEK, PEKK offers slightly better dimensional stability, a lower crystallization rate, and easier processability. This makes it a strong contender in applications where precision and material performance are critical.

Physical Attributes of PEKK Filament

1. High Strength and Toughness:

   • PEKK exhibits exceptional mechanical properties, offering excellent tensile strength, impact resistance, and rigidity.

2. Thermal Stability:

   • PEKK’s heat resistance is unparalleled, with a melting point of approximately 340°C and a glass transition temperature of around 160°C.

3. Chemical Resistance:

   • PEKK is resistant to a wide range of chemicals, including acids, bases, hydrocarbons, and solvents.

4. Dimensional Stability:

   • Its slower crystallization rate reduces warping and improves dimensional accuracy, making it more manageable during printing.

5. Lightweight:

   • Despite its strength, PEKK is much lighter than metals, offering an excellent strength-to-weight ratio.

6. Biocompatibility:

   • Certified PEKK materials can be used in medical and dental applications, such as implants and prosthetics.

Applications of PEKK Filament

PEKK’s unique combination of properties makes it ideal for use in:

1. Aerospace:

   • Components such as brackets, ducting, and housings that require high strength, lightweight characteristics, and resistance to extreme temperatures.

2. Automotive:

   • Used for parts exposed to high stresses and temperatures, such as engine components and under-the-hood applications.

3. Medical Devices:

   • Ideal for surgical tools, dental implants, and other biocompatible devices.

4. Industrial:

   • Suitable for gears, seals, and bearings that endure mechanical stress and chemical exposure.

5. Prototyping:

   • Advanced prototyping in research and development, where precise, high-performance materials are required.

Advantages of Using PEKK Filament

1. Exceptional Mechanical Properties:

   • Offers outstanding strength, stiffness, and impact resistance, rivaling metals in performance.

2. Thermal Resistance:

   • Withstands extreme temperatures, making it suitable for high-heat environments.

3. Chemical Durability:

   • Resistant to aggressive chemicals, extending the lifespan of parts in corrosive conditions.

4. Dimensional Accuracy:

   • The lower crystallization rate compared to PEEK reduces warping and improves precision, even for complex designs.

5. Lightweight Alternative to Metals:

   • Provides a high strength-to-weight ratio, reducing the overall weight of components.

6. Biocompatibility:

   • Meets medical and food-grade standards, expanding its applications in healthcare and food processing.

7. Improved Processability:

   • Easier to print than PEEK due to its slower crystallization rate, requiring less stringent cooling control.

Disadvantages of Using PEKK Filament

1. High Cost:

   • Like PEEK, PEKK is expensive, limiting its accessibility to specialized or high-value applications.

2. Specialized Equipment Needed:

   • Requires a high-temperature 3D printer capable of reaching extruder temperatures of 360°C+ and heated beds of 120°C+.

3. Moisture Sensitivity:

   • Hygroscopic in nature, requiring proper storage in an airtight container with desiccants.

4. Printing Challenges:

   • While easier to print than PEEK, PEKK still demands precise calibration, advanced hardware, and optimal environmental control.

5. Post-Processing Requirements:

   • May require annealing to achieve optimal mechanical properties, adding an extra step to the workflow.

Printing Tips for PEKK Filament

To achieve the best results with PEKK filament, consider the following tips:

1. Printer Compatibility:

   • Use a 3D printer designed for high-performance materials, with a high-temperature extruder, heated bed, and enclosed build chamber with active temperature control.

2. Dry the Filament:

   • Dry PEKK filament at 120-150°C for several hours before printing to avoid moisture-related issues.

3. Temperature Settings:

   • Set the extruder temperature between 360-400°C and the heated bed temperature to 120-150°C.

4. Adhesion:

   • Use a heated bed with a PEI sheet or apply adhesion aids like Kapton tape or specialized adhesives.

5. Printing Speed:

   • Print at slower speeds (15-30 mm/s) to improve accuracy and layer bonding.

6. Annealing:

   • Post-process printed parts in an oven at a controlled temperature to enhance crystallinity and mechanical properties.

7. Storage:

   • Store in an airtight container with desiccants to prevent moisture absorption.

Conclusion

PEKK filament is a versatile and high-performance material that excels in demanding applications. Its exceptional strength, thermal stability, and chemical resistance make it a top choice for industries such as aerospace, automotive, and healthcare. While it shares many properties with PEEK, PEKK offers better dimensional stability and easier processing, making it more accessible for advanced manufacturing projects.

Despite its high cost and demanding printing requirements, PEKK is an invaluable tool for creating parts that need to perform in extreme conditions. For professionals with the right equipment and expertise, PEKK filament opens the door to a new level of innovation and precision in additive manufacturing.