Tribological behaviour of fused deposition modelling printed short carbon fibre reinforced nylon composites with surface textures under dry and water lubricated conditions

Fused deposition modelling (FDM) printed short carbon fibre reinforced nylon (SCFRN) composites were fabricated. The friction and wear behaviour of printed materials were systematically investigated under both dry sliding and water lubricated conditions. The results showed that with short fibre enhancements, the printed SCFRN achieved a lower friction coefficient and higher wear resistance than nylon under all tested conditions. Further, under water lubricated conditions, the printed SCFRN exhibited a low, stable friction coefficient due to the cooling and lubricating effects of water. However, the specific wear rate of the printed specimens could be higher than that obtained under dry sliding conditions, especially when the load was relatively low. The square textured surface was designed and created in the printing process to improve materials’ tribological performance. It was found that with the textured surface, the wear resistance of the printed SCFRN was improved under dry sliding conditions, which could be explained by the debris collection or cleaning effect of surface texture. However, such a cleaning effect was less noticeable under lubricated conditions, as the liquid could clean the surface effectively. On the other hand, surface textures could increase the surface area exposed to water, causing surface softening due to the higher water absorption rate. As a result, the samples having surface textures showed higher wear rates under lubricated conditions. The work has provided new insights into designing wear resistant polymer materials using three-dimensional (3D) printing technologies, subjected to different sliding conditions.