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DESIGN METHODOLOGY FOR MICROENGINEERED FLUID DEVICES

Objective


In addition to providing a basic interfacing technology the project involved the design and development of generic fluidic demonstrators, the realisation of the component parts and the illustration of their potential by characterising the resulting system performance.

The project involved the design of fluid pumps, valve, flow sensors, turbines and conductivity sensors, in addition to the passive fluid interconnects and required the development of the associated modelling software. In particular, the modelling required the development of a practical means of incorporating mechanical movement within a general fluid dynamics model and the validation of the fluid dynamics models for the fluid motion in microchannels. The success of this design tool was illustrated in its successful analysis of bidirectional pumping action.

Two main actuation methods, electrostatic and thermopneumatic, were successfully demonstrated in the pump designs with the electrostatic approach providing low power dissipation and fast response times while the lower efficiency thermopneumatic approach yielded a potentially more robust design. In parallel, flow sensors were developed covering a wide dynamic range by utilising complementary drift-diffusion (quasi static) and (dynamic) time of-flight approaches.

The project successfully showed that this approach was feasible with the partners across the project contributing components to a primary (low pressure) demonstrator which included both electronic and fluidic interfaces in the form of an electrical wiring substrate and a fluidic backplane respectively. In achieving this goal a number of difficulties had to be overcome. In particular these concerned the development of low stress joining techniques, procedures for priming of the whole system and maximising yield in the multi-component demonstrator assemblies. In addition to this main demonstration, a secondary micro-turbine demonstrator was used to investigate the potential for microfluidic power tools in a high pressure microfluidic system. These systems also successfully demonstrated the use of a fluidic backplane as a particular means of interconnecting fluidic devices from different sources.
This research programme has as its objective the development of design methodology for the fabrication of miniature fluid devices using micromachining processing.

Micromachining,the application of technics,similar to those used in the semi-conductor industry for silicon processing,to form three-dimensional structures has been used to construct a variety of sensors and prototype fluid devices. At present, however, design and fabrication of these devices,from choice of material to final interfacing is based on an "ad hoc" approach,and requires a much more systematic and consistent methodology before it can be used in manufacturing. The work is being undertaken by research groups with complementary expertise,and is divided into eight main topics; fabrication in which etching and bonding technics on silicon and other materials will be estabilished to produce truly three-dimensional structures, modelling of the electrical, mechanical and thermofluid properties to take account of the much smaller length scale, materials assessment through a series of basic tests covering mechanical,surface and compatibility aspects,interfacing on the basis of an innovative modular approach which it is hoped will lead to a standard procedure for these devices,device fabrication in which the previous tasks are used to fabricate and test individual components,design of a generic integrated fluid circuit which will provide a test the methodology developed during the programme,system fabrication to give a demonstrator consisting of a generic fluid handling device, and testing on a systematic basis,with exchange of procedures and devices between partners.

A generic fluid demonstration device will allow the potential applications in the fields of robotics, analytical equipment and medicine to be assessed and developed.

The potential market for this enabling technology can be quantified in relation to growth in the total market for micromechanical devices,estimated at² between 15 and 20%over the next ten years.

Call for proposal

Data not available

Coordinator

GEC Marconi Ltd
Address
Elstree Way
WD6 1RX Borehamwood
United Kingdom
 

Participants (4)

Fraunhofer-Gesellschaft zur Förderung der Angewandten Forschung eV (FhG)
Germany
Address
Hansastraße 27D
80686 München
 
Heriot-Watt University
United Kingdom
Address
Riccarton
EH14 4AS Edinburgh
 
SIEMENS AG
Germany
Address
Siemensdamm 50-54
13629 Berlin
 
TWENTE TECHNOLOGY TRANSFER BV
Netherlands
Address
(Pobox 3639)
7500 DP Enschede