IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Tribology Tuesday Sessions
       Session TR+MM-TuP

Paper TR+MM-TuP4
Measurement of Rolling Friction for MEMS Applications

Tuesday, October 30, 2001, 5:30 pm, Room 134/135

Session: Poster Session
Presenter: T.-W. Lin, University of Maryland
Authors: T.-W. Lin, University of Maryland
D. Wendland, University of Maryland
B. Shapiro, University of Maryland
R. Ghodssi, University of Maryland
Correspondent: Click to Email
Friction has been a major concern in addressing MEMS reliability. The friction force is expected to be less when only rolling friction exists between two relatively moving components in MEMS devices. This concept is examined by a proposed experimental system using 300 µm diameter ball bearings to characterize static and dynamic rolling friction. The system consists of a servomotor, linkages, a platform, sliding rails, a CCD camera, and silicon specimen. The motor combined with the linkages provides the platform with a linear oscillating motion. A silicon plate (stator), 1cm*1cm*500µm, attached on the platform, has two parallel micromachined v-grooves on its top surface. Equal numbers of stainless steel micro-balls are placed in each of the v-grooves. Another silicon plate (slider), identical to the stator, rests on the micro-balls. The gap between two plates is designed to be 3 µm. The micro-balls are in contact only with the walls of the stator and slider v-grooves. The rolling friction at the contact points causes the slider to move along the direction of oscillation of the stator. The camera is used to record the slider's positions over time to determine velocity and acceleration of the slider. The dynamic coefficient of friction is computed by dividing the acceleration of the slider with the acceleration due to gravity. A curve for the instantaneous coefficient of friction is derived. Preliminary results for rolling friction of micromachined silicon surfaces in contact with stainless steel micro-balls will be presented.