Dry sliding wear behaviour of 3D printed Polyetheretherketone with varying layer thickness

Abstract

The additive manufacturing process fabricates parts with various parameters and surface features, significantly impacting the structure and mechanical properties of the part. Polymers like Polyetheretherketone (PEEK) demonstrate excellent wear resistance, and it is feasible to be processed with high-temperature polymer additive manufacturing with different surface features for applications such as bearings. The variation in layer thickness of the 3D printed part will result in different surface features and influencing their contact characteristics and wear response. In applications requiring lubrication, like bush bearing, the 3D-printed samples with layered structures can be advantageous by providing space between layers for lubricant storage. The layer thickness affects crystallinity, indentation hardness, tensile strength, surface roughness and energy. Surface roughness impacts the contact mechanism, and surface energy affects the adhesion of 3D-printed cuboid samples with a bearing steel counter body during a dry sliding test using a pin-on-disc configuration for an hour. PEEK's friction coefficient and wear rate increase with layer thickness, and the maximum wear rate of 8.3 × 10⁻⁵ mm³/Nm and friction coefficient of 0.62 by the sample with 0.3 mm layer thickness. The space/grooves between layers were observed to accommodate wear debris and influence the wear process during the test. The transfer layer formation on the steel surface affects the wear rate and mechanism, which is influenced by the trapped debris between the grooves formed by stacked layers of the sample surface.