Year of Publication

2017

Degree Name

Master of Science in Mechanical Engineering (MSME)

Document Type

Master's Thesis

College

Engineering

Department

Mechanical Engineering

First Advisor

Dr. Christine Ann Trinkle

Abstract

The non-contact nature of magnetic actuation makes it useful in a variety of microscale applications, from microfluidics and lab-on-a-chip devices to classical MEMS or even microrobotics. Ferromagnetic materials like nickel are particularly attractive, because they can be easily deposited and patterned using traditional lithography-based microscale fabrication methods. However, the response of ferromagnetic materials in a magnetic field can be difficult to predict. When placed in a magnetic field, high magnetization is induced in these ferromagnetic materials, which in turn generates force and/or torque on the ferromagnetic bodies. The magnitude and direction of these forces are highly dependent on the type of material used, the volume and aspect ratio of the ferromagnetic material, as well as the spatial distribution and magnitude of the magnetic field. It is important to understand these complex interactions in order to optimize force and torque generated, particularly given common limitations found in microfabrication, where it is often challenging to deposit large volumes of ferromagnetic material using conventional microdeposition methods, and power availability is also often limited, which in turn limits the ability to generate strong electromagnetic fields for actuation.

This work represents a theoretical analysis and experimental validation in macro scale to determine best practices when designing ferromagnetic actuators for microscale applications. Specifically, the use of nickel thin film prisms actuated in spatially uniform electromagnetic fields. These constraints were chosen because uniform magnetic fields can be readily generated with a simple and inexpensive Helmholtz coil design, and the uniformity makes actuation force independent of location, minimizing the need for spatial precision in devices. Nickel can also be easily deposited using evaporation or sputtering, generally in forms of thin-films.

Digital Object Identifier (DOI)

https://doi.org/10.13023/ETD.2017.345

Share

COinS