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Surface Friction Guiding For Reduced High-Frequency Lateral Vibration Of Moving Media, V. Kartik, Jonathan A. Wickert
Surface Friction Guiding For Reduced High-Frequency Lateral Vibration Of Moving Media, V. Kartik, Jonathan A. Wickert
Jonathan A. Wickert
The free and forced vibration of a moving medium is examined in an application where distributed friction guiding is used to control lateral position passively. Subambient pressure features formed in the guides intentionally modify the naturally occurring self-pressurized air bearing and increase the contact force between the medium and the guide's surface. These features increase friction to a level beyond that achievable based on the nominal wrap pressure. The moving medium is modeled as a beam that is transported over frictional regions and subjected to prescribed boundary disturbances arising from runout of a supply or take-up roll. For axial transport …
Static Friction And Surface Roughness Studies Of Surface Micromachined Electrostatic Micromotors Using An Atomic Force/Friction Force Microscope, Sriram Sundararajan, Bharat Bhushan
Static Friction And Surface Roughness Studies Of Surface Micromachined Electrostatic Micromotors Using An Atomic Force/Friction Force Microscope, Sriram Sundararajan, Bharat Bhushan
Sriram Sundararajan
A technique to measure the static friction forces (stiction) encountered in surface micromachined micromotors using a commercial atomic force microscope (AFM)/friction force microscope has been developed and is described. An AFM tip is pushed against a rotor arm of the micromotor so as to generate lateral deflection (torsion) of the tip, which is measured by the AFM. The maximum value of the lateral deflection obtained prior to rotor movement (rotation) is a measure of the static friction force of the micromotors. This technique was employed to study the effect of humidity and rest time on the static friction force of …
Topography-Induced Contributions To Friction Forces Measured Using An Atomic Force/Friction Force Microscope, Sriram Sundararajan, Bharat Bhushan
Topography-Induced Contributions To Friction Forces Measured Using An Atomic Force/Friction Force Microscope, Sriram Sundararajan, Bharat Bhushan
Sriram Sundararajan
Most friction studies using an atomic force/friction force microscope, while concentrating on material-induced effects, often present users with conflicting and confusing interpretations of the topography-induced friction forces. It has been generally reported that topography-induced contributions are independent of scanning direction and can be removed by subtracting friction data from forward and backward scans. In this article, we present friction studies on samples with well-defined topography variations and find that the above-given statement is not generally true. At surface locations involving significant changes in topography, the topography-induced contributions to friction forces are found to be different between forward and backward scanning …