Control tribological and mechanical properties of MEMS surfaces. Part 1: critical review

Rymuza, Z.

doi:10.1007/s005420050160

Cited by 94 publications

(45 citation statements)

References 25 publications

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“…The fabrication of micromotors in MEMS is mainly based on silicon and its compounds and their tribological behavior plays an important role in the performance of such systems [17]. Materials are important to reduce friction and wear and therefore to improve reliability and to extend lifetime.…”

Section: Discussionmentioning

confidence: 99%

Friction and wear study of the hemispherical rotor bushing in a variable capacitance micromotor

Zhang

Meng

2005

Microsyst Technol

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Friction and wear are the most serious problems for micromotors in microelectromechanical systems (MEMS). In the paper, a linear-sliding wear model of the contact between the rotor bushing and the ground plane is presented to describe the wear and a corresponding simplified method is proposed to simulate the wearing process. The effects of geometry parameters, material properties and applied operating conditions on the evolution of dimensional and volumetric wear rates and frictional torques are explored for normally loaded rotating rotor bushing sliding on the ground plane. A hemispherical-bushing-on-ground-plane configuration finite element model (FEM) is set up and the implementation of the contact task based on ANSYS and the contact element approach is introduced to provide the numerical simulations acted as a guide to solution of the contact problems in micromotors. Numerical simulations and results of the wear rates, frictional torques, contact stresses and contact pressure are studied and the effects of roughness, material properties, geometry parameters and FEM mesh of the bushing and the ground plane are discussed. It is indicated that the nonlinear effects cannot be ignored and the results should not be used to predict the absolute wear lifetime whereas surface engineering, lower wear materials and rational designs for micromotors in MEMS should be applied to bring the friction and wear behaviors into the acceptable regimes.

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Section: Discussionmentioning

confidence: 99%

Friction and wear study of the hemispherical rotor bushing in a variable capacitance micromotor

Zhang

Meng

2005

Microsyst Technol

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“…For side-drive motors, this is partly due to fabrication limitations; the torque output of electrostatic side-drive motors is proportional to the length of the statorrotor side-wall, however, fabrication of high wall depths requires high aspect-ratio photolithography and thick resist coatings that compromises linewidth resolution. This places lower bounds on the air gap and bearing clearances that need to be minimized for high torque and low friction [11,45]. One potential solution is to use LIGA processes that can fabricate high aspect ratio structures [46].…”

Section: Design and Fabrication Issuesmentioning

confidence: 99%

A brief review of actuation at the micro-scale using electrostatics, electromagnetics and piezoelectric ultrasonics

Liu

Friend

Yeo

2010

Acoust. Sci. & Tech.

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Though miniaturization and mass production via integrated circuit fabrication techniques have transformed our society, the methods have yet to be successfully applied to the generation of motion, and as a consequence the many potential benefits of microrobotics has yet to be realized. The characteristics of electrostatic, electromagnetic and piezoelectric transduction for generating motion at the micro scale is considered, employing scaling laws and a reasoned consideration of the difficulties in motor fabrication and design using each method. The scaling analyses show that electrostatic, electromagnetic and piezoelectric actuators all have comparable force scaling characteristics of F / L 2 ; if one employs permanent magnets, electromagnetic forces do not scale as F / L 4 . Though the torque, (, of piezoelectric ultrasonic motors scale rather poorly with ( / L 4 , they have the clear advantage of possessing torque amplitudes some two orders of magnitude larger than motors employing the other transduction schemes at the micro scale.

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“…Electrostatic actuation has become a favorable actuating method due to it could produce large surface forces on microstructures. Electrostatic micromotors have three types including the variable capacitance, the electroquasi-static induction micromotors and wobble micromotors (Rymuza 1999; Bart et al 1992). The driving torque of electrostatic micromotors is rather small, and lifetime is limited due to the complex tribological issues, such as stiction, wear and friction.…”

Section: Introductionmentioning

confidence: 99%

Slip model for the ultra-thin gas-lubricated slider bearings of an electrostatic micromotor in MEMS

et al. 2009

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A new slip model derived by molecular dynamics has been used to investigate the ultra-thin gaslubricated slider bearings beneath the three bushings of an electrostatic micromotor in micro-electro-mechanical systems (MEMS). Modified Reynolds equation is proposed based on the modified slip model. Analytical solutions for flow rate, pressure distribution, load carrying capacity and streamwise location using the modified Reynolds equation are obtained and compared with the results gained from those in the literature. It demonstrates that the new secondorder slip model is of greater accuracy than that predicted by the first-order, second-order slip models and MMGL model and produces a good approximation to variable hard sphere (VHS) and variable soft sphere (VSS) models, which agree well with the solution obtained from the linearized Boltzmann equation. It is indicated that the slip effect reduces the pressure distribution and load carrying capacity, and shifts the streamwise location of the load carrying capacity, which should not be ignored to study the step-shaped slider bearings in micromotors for MEMS devices.

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Control tribological and mechanical properties of MEMS surfaces. Part 1: critical review

Abstract: The problem of modification of rubbing surfaces in micrometer size microdevices (micro-electro-mechanical systems -MEMS) to control adhesion, friction and wear as well as mechanical properties is discussed. Several solutions are reviewed and examples of investigation results are given.

Cited by 94 publications

References 25 publications

Friction and wear study of the hemispherical rotor bushing in a variable capacitance micromotor

Friction and wear study of the hemispherical rotor bushing in a variable capacitance micromotor

A brief review of actuation at the micro-scale using electrostatics, electromagnetics and piezoelectric ultrasonics

Slip model for the ultra-thin gas-lubricated slider bearings of an electrostatic micromotor in MEMS

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