An electromagnetically actuated rotary gate microvalve with bistability

MEMS;Microfluidics;Gate microvalve;Compliant micromechanism;Bistability;Rotary;Electromagnetic actuator;Particulate flow;High flow;Permalloy;Microfabrication;Electroplating;Torque measurement;Flow characterization

Luharuka, Rajesh ; Mechanical Engineering

University:Georgia Institute of Technology

Department:Mechanical Engineering

关键词: MEMS;    Microfluidics;    Gate microvalve;    Compliant micromechanism;    Bistability;    Rotary;    Electromagnetic actuator;    Particulate flow;    High flow;    Permalloy;    Microfabrication;    Electroplating;    Torque measurement;    Flow characterization;   

Others  :  https://smartech.gatech.edu/bitstream/1853/22576/1/luharuka_rajesh_200705_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

Two types of rotary gate microvalves are developed for flow modulation in a microfluidic system that operates at high flow rate and/or uses particulate flow. This research work encompasses design, microfabrication, and experimental evaluation of these microvalves in three distinct areas compliant micromechanism, microfluidics, and electromagnetic actuation. The microvalve consists of a suspended gate that rotates in the plane of the chip to regulate flow through the orifices. The gate is suspended by a novel fully-compliant in-plane rotary bistable micromechanism (IPRBM) that advantageously constraints the gate in all other degrees of freedom. Multiple inlet/outlet orifices provide flexibility of operating the microvalve in three different flow/port configurations. The suspended gate is made of a soft magnetic material and is electromagnetically actuated like a rotor in a variable-reluctance stepper motor. Therefore, an external electromagnetic (EM) actuation at the integrated set of posts (stator) causes the gate mass to switch from its default angular position to a second angular position. The microvalve chip is fabricated by electroplating a soft magnetic material, Permalloy (Ni80Fe20) in a sacrificial photoresist mold on a Silicon substrate. The inlet/outlet orifices are then etched into the Silicon substrate from the back-side using deep-reactive ion etch process. Finally, the gate structure is released by stripping the PR and seed layers. This research work presents the realization of a new microvalve design that is distinct from traditional diaphragm-type microvalves. The test results are encouraging and show the potential of these microvalves in effectively modulating flow in microfluidic systems that may not require a tight seal. The microvalve uses a novel in-plane rotary bistable micromechanism that may have other applications such as optical shutters, micro-locks, and passive check valves.