A new approach for high-quality production of UHMWPE by applying powder vibration densification before sintering

Abstract

Due to its extreme viscosity, UHMWPE powder requires elevated pressure and temperature settings to ensure a fully solid structure. But a gentle process is vital for reliability in certain applications, such as prosthetic liners. A unique type of large gap, not mentioned in the literature, has been observed to resist closing more than regular gaps due to the number of particles forming a shield against pressure. As a solution, a mechanical vibration treatment of the particles before heating was used to eliminate these particular large gaps. Optimum vibration parameters were found, and the samples' final solid density and mechanical properties increased. The particles' dimensions and coefficient of friction were measured, and their vibration-dependent characteristics were discussed. A custom-made microscope apparatus was used to observe the vibration-induced densification of the particles and the gaps resisting closing.