Another dimension

The ability to manufacture increasingly complex microengineered components has been given a boost with the launch next month of a joint research project based at Scotland’s Heriot-Watt University.

Microengineered components are perhaps more pervasive than people think, taking in airbags and tyre pressure sensors. While typically produced using traditional 2D semiconductor manufacturing processes these components have found applications far beyond the semiconductor industry.

One recent example is the design of microgenerators for heart pacemakers. To an extent, though, the development of microengineered technology has reached an impasse; it is felt that conventional design and manufacturing cannot support the further evolution of this technology and there is a risk that such devices will remain at the ‘crafted prototype stage’.

This barrier is the lack of technology or ideas in development to make the move away from the 2D layer-by-layer manufacturing approach used in semiconductor production and towards full 3D design and manufacture.

So this latest project — over four-years and funded by the EPSRC — will aim to create a paradigm shift not just in manufacturing technology, but in the strategic approach required for the production of highly integrated, cost-effective and reliable multi-functional 3D miniaturised devices.

Principle project investigator Dr Marc Desmulliez explained that the key aim of the research is to move the technology from 2D to 3D and from prototype to manufacturing capacity. ‘As far as semiconductor manufacturing technology is concerned, most of the products made are essentially 2D,’ he said.

‘You effectively pile layer upon layer to create functionality in the third dimension. With microengineering technology that changes slightly, but it still borrows from semiconductor technology. What we are trying to do is break the mould and find new ways to manufacture micron scale 3D objects.’

At the highest level, 3D ‘mintegration’ (the design and manufacture of miniaturised, integrated 3D products) will build on three manufacturing philosophies.

• Lamination: Here products are built up from sheets of embedded components and interconnect.
• Lego-type building block construction: Structures evolve from the joining of blocks, which have a level of functionality integrated into them, leading to the growth of 3D forms that may favour the construction of sensors.
• Folding construction: In this method planar structures are folded to occupy a defined 3D space. This origami-like approach could allow products to flex into their applications environment.

Using one or more of these philosophies, Desmulliez foresees within three years there will be tangible products which will demonstrate the applications that would benefit from this new form of design and manufacturing. He said he is talking to a number of unspecified UK defence companies with a view to producing small 3D mechanical systems to assist them in fitting greater amounts of technology into ever-smaller weaponry. Other products include health and usage monitoring systems and multi-sensor systems for use in difficult-to-access areas.

The project’s 26-strong team,including researchers from the National Physical Laboratory and Cambridge, Cranfield, Greenwich, Loughborough and Nottingham universities, will provide designs and manufacturing toolsets to aid companies to implement these changes.

It is hoped the new design and manufacturing techniques envisaged by the project will form the basis for next-generation automotive, aerospace, telecommunications, medical and consumer products.

The Loughborough team has been applying microelectronics research to the field of medical devices, and has designed and prototyped an intelligent pulmonary drug delivery. Nottingham, which is working on drug delivery systems, believes that the key issue is the high-accuracy assembly of multi-material 3D products. And Cambridge’s Institute for Manufacturing is working on the development of precision micromachining with ultrafast lasers. This research is expected to help in the production of a wide range of tooling and direct component fabrication routes in any material from polymers to diamonds.

The concept of laser form printing has been proposed to overcome current micro-fabrication limitations found in single shot laser patterning. It will not be restricted to simple polymeric structures as the process should be capable of producing complex polymeric, ceramic and metallic-micro features.

Essentially, the project is designed to be thought provoking and look beyond the technology and try and move it out of the R&D labs. ‘It is a kind of chicken and egg situation, where because the technology is not there, there is no demand. We are trying to break that cycle,’ said Desmulliez.

Applications for this technology are extensive. Desmulliez believes monitoring and healthcare are key areas which may benefit, from internal monitoring of computers to notify you when a chip has failed, to more practical and everyday levels such as a sensor inserted in a shoe which will let you know when the rubber in your sole has worn out. Current commercial markets are also attractive.

 ‘Look at the camera on your mobile phone,’ said Desmulliez. ‘Three years ago there was no business, now it is worth $300m (almost £160m) a year. If it is possible to manufacture more cheaply to bring the cost of mobiles down further, that is one area we will look at.’