Wear of ultra-high molecular weight polyethylene manufactured with laser powder bed fusion

Abstract

Ultra-high molecular weight polyethylene (UHMWPE) is widely used in applications that need abrasion resistance, impact toughness, and chemical inertness, including bushings, prosthetic joints, naval dock bumpers, and mooring buoys. However, its high molecular weight restricts conventional processing to ram extrusion or compression molding, which require a die or mold that limits the complexity and customizability of part geometries. Additive manufacturing (AM) offers an alternative to producing complex UHMWPE parts without the need for specialized tooling. Recent advances have demonstrated AM of UHMWPE via a process chain that combines laser powder bed fusion (L-PBF) with a pressure-assisted thermal post-processing step. However, despite the critical importance in most of its applications, no information exists about wear of L-PBF printed UHMWPE compared to that of conventionally processed parts. Here, UHMWPE specimens of controlled density are produced using the L-PBF process chain and their process-structure-wear relationship is characterized. The results reveal that the steady-state wear rate decreases exponentially with increasing density and approaches that of conventionally processed benchmark specimens. This improvement is attributed to reduced porosity and corresponding increased hardness. This study provides the first process-structure-wear relationship for additively manufactured UHMWPE, and demonstrates that L-PBF can deliver wear resistance comparable to conventional processing while enabling complex, customized geometries. These findings establish a scientific and technological foundation for extending L-PBF of UHMWPE into advanced applications such as precision bushings, orthopedic components, and other high-performance parts that require both geometric freedom and excellent tribological performance.