Implementing Lubrication in Micro-Electro-Mechanical Systems

Completed

Energy Efficiency(Other)
Not Energy Related
Other Power and Storage Technologies(Electric power conversion)
Renewable Energy Sources(Other Renewables)

Basic and strategic applied research

ENGINEERING AND TECHNOLOGY (Mechanical, Aeronautical and Manufacturing Engineering)

Not Cross-cutting

Dr T Reddyhoff
Department of Mechanical Engineering
Imperial College London

Standard

EPSRC

01 July 2013

30 June 2015

24 months

£235,107

Info. & commun. Technol.

London

NC : Engineering

Dr T Reddyhoff, Department of Mechanical Engineering, Imperial College London

Project Contact, Tribosonics Ltd
Project Contact, Micro Materials Ltd
Project Contact, PCS Instruments

Micro-electro-mechanical systems (MEMS) are tiny (sub-millimetre) machines, which have arisen from advances in semiconductor fabrication. Typical MEMS devices include air-bag accelerometers, gyroscopes in smartphones and implanted drug-delivery meters. The MEMS industry is currently worth around 10 billion dollars. Furthermore, their low cost, high tolerances, and ability to combine sensors and actuators with microprocessors, give MEMS the potential to profoundly affect our way of life. Unfortunately however, high friction and wear means that current commercial MEMS designs are confined to non-, or very low sliding devices. This precludes the possibility of rotating or reciprocating MEMS such as micro-engines. Clearly, there are huge possibilities if this can be changed.Research efforts to tackle the problem of friction in MEMS have suggested lubrication by liquids and vapours as possible solutions since these can continually replenish protective films on rubbing surfaces. Arguably the most promising has been liquid lubrication as my research on silicon micro-contacts has shown. To date, I have demonstrated the effectiveness of liquid lubrication in model, silicon MEMS-type, contacts but no validation has been carried out on a working MEMS device. The proposed project aims to carry out this validation and thus bridge the gap between lubrication research and the production of a commercial sliding MEMS device. To achieve this, I will collaborate with MEMS manufacturers to produce a micro-journal bearing and incorporate this into a MEMS turbine energy harvester. This is a very suitable application since energy harvesters are a rapidly growing area that would significantly benefit if low friction sliding contacts were possible.The project will break down the bearing production process into a series of studies, each dealing with a different aspect of lubrication and bearing design. These steps include addressing issues such as lubricant containment, evaporation and delivery, optimisation of bearing geometry and adaptation of fabrication techniques. In addition to the goal of producing a MEMS turbine that runs on hydrodynamic micro-bearings, a number of more fundamental avenues of research, involving tribology and silicon MEMS, will be explored. These include a feasibility study into the development of sliding MEMS with compliant surfaces. Finally, silicon MEMS technology will be used to enhance my tribology research by i) coupling fabricated silicon components with existing infrared microscopy equipment so that the temperature of rough surface contacts can be imaged - this is possible since silicon is transparent to infrared; ii) coating thin-film piezoelectric sensors onto silicon specimens to monitor lubricant film thickness using ultrasound

16/08/13