Exploring Process‐Structure–Property Relationships of PEKK and PEEK in Fused Filament Fabrication

High‐performance polymers (HPP) have gained significant attention in recent years because of their potential for metal replacement in industries with demanding environments, such as aerospace, where high‐strength lightweight parts are essential. A critical area of research for HPPs is additive manufacturing (AM). Polyetherketoneketone (PEKK) and polyetheretherketone (PEEK) stand at the forefront of this research owing to their excellent mechanical, chemical, and physical properties while making them ideally suited for metal replacement applications in aerospace. Fused filament fabrication (FFF) is a key processing methodology in AM, offering a promising approach to manufacturing PEKK and PEEK. This review explores the process‐structure–property relationships of PEEK and PEKK manufactured using FFF, focusing on the impact of processing parameters on the material's mechanical properties. Although PEEK has been extensively studied, a significant gap exists in the literature concerning PEKK's behavior under similar circumstances. This review highlights the need for further investigation into the FFF processing of PEKK and its effects on PEKK's unique chemical structure.