Friction Performance of Three-Dimension Printed PEEK for Journal Bearing Application Under Grease Lubrication

Abstract Additive manufacturing revolutionizes component and part creation, offering unmatched flexibility and reducing production time. This innovation, especially significant with semicrystalline polymers like polyetheretherketone (PEEK) at high temperatures, expands applications, including sleeves and bushes. PEEK's mechanical and tribological properties make it an attractive long-term metal replacement. However, the 3D printed PEEK surface is pivotal, and the surface structure depends on infill density, which influences its response to sliding conditions, such as speed, load, and test duration. The PEEK structure's surface patterns facilitate lubricant accommodation, particularly during boundary lubrication tests, affecting the formation of a transfer layer. Surface properties directly impact friction in 3D printed PEEK against the counterbody. Lubrication decreases friction coefficients compared to dry conditions. Wear tests show that 3D printed PEEK parts outperform extruded rod samples, displaying superior wear resistance. Surface texture and properties directly affect contact characteristics and lubricant storage. In journal bearings, varying infill percentages create surface voids, efficiently accommodating polyalphaolefin (PAO)-based grease in PEEK-based applications where oil is not preferred for sliding operations.