Let there be light

Groundbreaking research into the use of lasers for creating lightweight structures could herald the dawn of a new industrial era.

Alan Jocelyn, director of the Aerospace Manufacturing Research Centre at the University of West England, believes that we stand on the cusp of a new manufacturing era.

Developments in laser manufacturing technologies could, he said, bring about the demise of the ‘Victorian’ machining methods upon which we have relied for so long and enable the manufacture of metal structures with unprecedented complexity, strength and low weight.

Jocelyn is currently directing the spin-out of LIS Tech, a company that he hopes will bring about the commercialisation of the world’s first manufacturing cell entirely based on laser technology. ‘We will be able to produce the lightest, strongest, most fatigue-enduring structures ever produced at a fraction of the cost and with minimum damage to the environment,’ he claimed.

His vision is to use high-powered lasers for preparing, cutting, welding, drilling, trimming, forming and joining complex shapes. And at the heart of the system is the development of a technique known as laser induced super plasticity (LIS).

While most metals and their alloys soften as they are heated and become more ‘plastic’ in character, a small number of alloys (aluminium, iron and titanium) demonstrate incredible ductility at specific temperatures; allowing them to be stretched, or formed, to enormous extents. This phenomenon, known as superplasticity, has been understood since the 1930s, but is only beginning to fulfil its true potential now that modern laser-based methods are being applied.

Another effect of this phenomenon is that if two superplastic materials are brought together, atoms diffuse from one surface to the other in equal amounts, resulting in a homogenous joining of the two pieces. This process is known as diffusion bonding (DB) and results, said Jocelyn, in the strongest form of joining metals known to man.

While there’s been plenty of academic research into superplasticity, relatively little work has been done on related industrial processes. ‘There is no other process that gives you the accuracy of suplerplasticity,’ said Jocelyn. ‘there is no residual stress in a part produced this way and it will fit perfectly – you can produce whole structures out of flat sheet metal – and if you can do all of that, then for the first time we could embrace the phenomenon of superplasticity in a proper cost-effective manner.’

‘With lasers we can do completely different things,’ said Jocelyn. ‘We can cut metal, soften metal and shape it with gas, superplastically form and diffusion bond structures together so we don’t need to use nuts, bolts and rivets. We can even use a laser to induce a shockwave in a material in order to improve its performance.’

So confident is he of the potential of laser-based manufacturing that he believes that within 20 years laser manufacturing equipment will have replaced conventional machine tool equipment in a huge number of machining facilities.

So far, the work has focused on the superplastic forming and diffusion bonding of titanium, which although difficult to form has strength and weight properties that make it of major interest to the aerospace industry. Jocelyn’s belief is that a new method of extraction of titanium from its ore, by electrolysis, will reduce its cost by up to 75 per cent, making it less expensive than stainless steel.

With the collaboration of four ‘major anglo-american aerospace companies’ already secured, Jocelyn impressively states his aim to be the provider of this technology to the rest of the world within 10-15 years.