Influence of Solid Lubricants on the Tribological Performance of Photocurable Resins for Vat Photopolymerization

Abstract

New developments in additive manufacturing (AM) are enabling the use of 3D printed parts in increasingly demanding applications, such as in mechanical power transmission systems, where excellent build quality and tribological performance are required. The tribological properties of thermoplastic-based AM technologies are well knowninject, whereas the performance of photopolymer-based AM technologies is very rarely explored. This study aims to provide new insight into the tribological performance of 3D printed parts produced using vat photopolymerization (VPP). Photocurable resins based on aliphatic urethane acrylate oligomers were modified with different solid lubricants (polytetrafluoroethylene (PTFE), graphite and molybdenum disulfide (MoS2)) and 3D printed using Digital Light Processing (DLP). The mechanical and thermal properties were studied using the tensile tests, Charpy impact tests, Shore D, and dynamic mechanical analysis (DMA). The tribological performance was studied using a Pin-on-Disk tribometer. Among the lubricants, PTFE had the highest impact on the coefficient of friction (µ) and the specific wear rate (ws). The hybrid lubricant system (PTFE/MoS2) resulted in excellent tribological performance, where the µ was reduced by up to 52% and ws by up to 92%.

A review of advances in tribology in 2020–2021

“…Fleming [192] did a study of physical vapor deposition (PVD) coatings, suspensions, and an ashless phosphate ester in oil at the interface of the upper die-workpiece and found that the mixing of MoS 2 micro-platelets and an ashless phosphate ester in oil showed tribological synergistic effect, which provided higher quality surface finish and greater protection against wear. Slapnik et al [193] improved tribological performance of the photopolymer-based material for additive manufacturing (AM) using vat photopolymerization (VPP) by modifying photocurable acrylates with different solid lubricants, PTFE, graphite, and MoS 2 . Lu et al [194] prepared a kind of self-lubricating composites that can adapt to different environments by adding reduced graphene oxide(RGO) and WS 2 into the Cu matrix.…”