1. Roer Eka Pawinanto, Jumril Yunas and Burhanuddin Yeop Majlis
Finite Element Analysis on Electromagnetic Actuator for Ultra Low Flow Fluid Injection
Roer Eka Pawinanto, Jumril Yunas and Burhanuddin Yeop Majlis
Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia, Bangi, Selangor, 43600, MALAYSIA
Abstract
Micro-actuators driven by electromagnetic field have gotten lot of attentions on many fields due to their compact structure, controlled high actuation force at very low power consumption and easy fabrication as well as ability for integration with Lab-on-Chip system. Reported here is a theoretical analysis of MEMS (Micro Electro mechanical System) Actuator that is driven by electromagnetic coil of micrometer size using FE (Finite Element)-Analysis. This work will focus on the actuator design which would be able to inject and transport the fluid at maximum flow-rate of 1 ml/min for a less than 100 mW of electrical power consumption. The actuator system consists of permanent magnetic material attached on a static substrate, air gap, and planar thin current carrying micro-coils embedded on elastic movable thin film membrane. The results showed that the proposed geometry of the coil and the permanent magnetic material affects significantly to the magnetic flux intensity that influences the Lorentz Forces on the membrane. The results of this work should greatly benefit to the development of lab-on-chip system for biomedical applications. r
Permanent Magnet
Micro Coil
Polymide Membrane
Actuator Design
Parameter Control
Analysis Results
Structure name
Material
Dimension
Substrate
Glass; Silicon
Permanent magnet
NdFeB; SmCo; Fe2O3
tmag=500 µm
dmag=2.5 mm
Micro-coils Cu
Space s=100 µm
Width w=100 µm
N= 5;6;7;8;9;10;15;20
Membrane
Polymide
tmem=100 µm
dmem=10.8 mm
Cross sectional view of integrated injector device
Br component at different height above the microcoil structure
Electromagnetic micro-actuator consists of a permanent magnet, radial shape micro-coil and thin film polyimide membrane.
Between permanent magnet and membrane, there is sufficient distance to enable membrane deflection at vertical direction.
Theoretically, when input current is supplied into a planar coil attached on a flexible membrane, an electromagnetic force will be generated and the membrane will deflect upwards and downwards.
The actuating membrane creates then pressure change in the chamber, hence enabling the transport of medium through the channel at a desire steady flow.
Parameter of the actuator system
At certain z-position between the coil and magnet, magnetic flux density is produces due to the superposition between generated magnetic flux from permanent magnet and induced magnetic flux of coil.
Magnetic flux density of 0.82 T and magnetic force on the membrane as high as 10.4 mN can be obtained for 20 µm thick Cu coil having 20 turns and supplied by a current of 0.5 A with NdFeb as permanent magnet.
The inner diameter of the coil is kept constant by din= 2.5 mm. Hence, increasing the coil parameters affects to the outer diameter of the device.
The magnetic materials used for observation are Neodymium (NdFeB), Samarium Cobalt (SmCo) and Hard Ferrite/Ceramic Fe2O3.
The distance between permanent magnet and coil surface is set to 100 µm.
The 2-D axis symmetry observation area is considered to 6x3 mm2.
Magnetic flux density (r-component)
at position between microcoil and permanent magnet
Basic of generated magnetic force
on current carrying coil
Magnetic Force for various turn number
CONCLUSION
In this work, a Finite Element analysis of the magnetic field driven actuator device has been reported. Changes in coil dimensions and permanent magnet materials have an impact on the resulting force. it is clearly shown that magnetic material and coil geometry play important factor to increase the force. The simulation results have shown that NdFeB permanent magnet material produces the highest force compared to other observed materials. Due to the planar structure, fluid injection using electromagnetic actuator can be easily integrated with microfluidic devices which shows very good prospect for the development of integrated Lab On Chip.
ACKNOWLEDGEMENT
For further, information please contact
Assoc. Prof. Dr. Jumril Yunas
Institute of Microengineering and Nanoelectronics
Universiti Kebangsaan Malaysia .
We would like to thank Ministry of Science and Technology for the research grant under the project SF0841 (Development of Intergrated Electromagnetic Micro-pump Based on Embedded Planar Micro-coil for Ultra Low Fluid Injection of Bio-Samples) and Universiti Kebangsaan Malaysia for the project grant NND/ND/(1)/TD (Development of lab-on chip for peripheral blood stem cell isolation and rapid detection of tropical diseases from blood).
ID: AA-PO3-14