A feasibility study of self-lubricating bearing prepared by three dimensional (3D) printing

초록

With the development of three dimensional(3D) printing technology, the 3D printed parts are used in various industrial fields of robot and machines. Recently, a variety materials including plastics, metals, and ceramics have been used in 3D printer according to the printing methods such as fused deposition modeling (FDM), stereolithography apparatus (SLA) and selective laser sintered (SLS). New materials and methods for 3D printing are constantly being studied and it is now possible to print even bearings. Among the bearings essential for mechanical parts, sintered bearings are made by compression and sintering processes of mixed solid lubricant powders such as metals, alloys and graphite powders. After that, the micro-porous created by the sintering process are filled with oil and can used for a long time without oil supply. The most important characteristic of sintered bearing is a micro-pore. The reason is that the self-lubrication occurs due to lubricant in micro-pores. Likewise, the SLS method also has a characteristic which is micro-pore due to the powder-based material is sintered with a laser. This characteristic of 3D printing technology will be advantageous for making self-lubricated bearings. Therefore, research on 3D printing bearings with self-lubricating properties is needed. In this paper, the friction characteristic of the 3D printed bearing made of SLS method is evaluated through the experiment. The experiment is performed under the load and various rotational speed in dry condition. The 3D printed specimen is immersed into the oil at the vacuum chamber for 12 hours. The specimen is fixed to the rotating shaft thus the lubricating oil is released from the micro-pores when the temperature rises by friction. The amount of supplied oil is measured by comparing the weight of specimen before and after the experiment. Through this study, feasibility of 3D printed bearing with self-lubricating property is evaluated.