Effect of Lubricant Viscosity on the Friction Behavior of the mm-scale Specimen

Abstract

The size of moving parts in MEMS (micro-electro-mechanical-systems) is often in the mm-scale or smaller. Affected by the size effect, the friction in the mm-scale is different from the friction larger systems. In this paper, a novel tribometer for mm-scale specimen has been introduced. The friction and film thickness has been measured by laser measurement technology, and hydrodynamic lubrication for mm-scale has been studied. The effect of the fluid viscosity on friction and film thickness was studied. The results shown that the sliding motion in the mm-scale follows the law of hydrodynamic lubrication, and friction is relatively large because of the mm-scale. For the higher viscosity lubrications, it is easier to form a film balance the load. However, at higher sliding speed, with higher viscosity lubrication comes more friction.