Post-Processing PEEK 3D-Printed Parts: Experimental Investigation of Annealing on Microscale and Macroscale...

Area of Science:

• Materials Science
• Polymer Science
• Mechanical Engineering

Background:

• Polyether ether ketone (PEEK) is a high-performance thermoplastic polymer with valuable properties for diverse applications.
• PEEK's high melting point (343 °C) complicates processing and necessitates post-processing treatments like annealing for optimal performance.
• Inadequate layer adhesion during printing due to thermal cycling requires annealing to ensure part integrity.

Purpose of the Study:

• To investigate the effects of annealing on the nanoscale surface morphology and macroscale mechanical properties of PEEK.
• To establish precise post-processing parameters for annealing PEEK to enhance its structural integrity and performance.
• To correlate nanoscale observations with macroscale mechanical behavior.

Main Methods:

• Atomic Force Microscopy (AFM) for high-resolution surface morphology analysis before and after annealing.
• Tensile testing to evaluate macroscale mechanical performance.
• Three-point bending tests to assess material response under flexural load.

Main Results:

• AFM revealed that higher annealing temperatures and longer durations reduce surface roughness by promoting polymer chain mobility, reorganization, and recrystallization.
• Tensile strength increased by 6.0 MPa for samples annealed at the highest temperature and longest duration compared to unannealed samples.
• Three-point bending tests showed a 16 MPa increase in strength for samples annealed at 360 °C for 6 hours compared to unannealed controls.

Conclusions:

• Optimized annealing significantly enhances PEEK's mechanical properties and structural integrity.
• The study provides crucial data for refining PEEK post-processing techniques.
• Findings support improved material quality for engineering and biomedical applications of PEEK.