Rapid manufacturing gathers pace: Interview with Graham Bennett, CRDM
Why has additive layer manufacturing not progressed as fast as once hoped? Paul Fanning asks one of its UK pioneers.
When the first stereolithography machines reached these shores in the early 90s, there were confident predictions that layer manufacturing was the technology of the future. Nearly 20 years later, it is apparent that progress was destined not to be as meteoric as was once hoped. Nonetheless, it now occupies an established place in design and manufacturing.
Graham Bennett, technical director of layer manufacturing specialist CRDM was one of the pioneers of this technology in the UK, having started with a rented stereolithography machine at what is now Buckinghamshire New University at a time when, as he puts it "there were only about nine other machines in the country".
Talking about the progress of the technology, Bennett says: "It's not where most of the industry expected it to be. At the start, you had the early adopters taking the technology on board and that inevitably meant a lot of machine sales. This meant that companies expected the machines to migrate naturally into the production environment. But they didn't really take into account how big the gap is between having a prototype made and having a production part made."
This gap is one that CRDM has spent many of the intervening years between its inception and today filling. Having now spun out from the University in 2007 and moved to its current premises in High Wycombe, the company has a range of layer manufacturing machines, as well as offering more traditional machining and injection moulding services – even acting as an agent selling Hewlett Packard's 3D printers.
Nonetheless, layer manufacturing is still close to Bennett's heart and its progress from a pure prototyping tool to a player in the manufacturing environment is one he is keen to foster. However, he recognises a range of problems that are still preventing this from happening. He says: "The problem is not that the technology cannot achieve what is required for production parts in certain circumstances, it's that the expectations of the customer need to be changed. That's almost a bigger problem because it takes in things like quality standards for inspection requirements. For instance, the finish will be different on an additive layer manufacturing machine to what you'll get on a moulded part – not better, just different. But overcoming that inertia of people's expectations and culture can be hard to overcome."
This 'inertia' preventing adoption of the technology takes a number of forms, Bennett believes, one of which is the fear of risk inherent to many big companies. "It required too many people to go out on a limb in big corporations – the 'nobody ever got sacked for buying IBM' mentality kicked in. But in smaller and medium-sized enterprises, where there was more flexibility, they've been able to adopt it."
Another major factor, of course, is the number of industries in which the importance of recognised quality standards create a barrier to the adoption of the technology for manufacturing purposes. Says Bennett: "There are no recognised quality standards for layer manufactured parts to go into flight components on aircraft. People are writing them, but as things stand, if you send a metal part into an aircraft manufacturer, the first thing they'll do is look up which quality standard he should apply to test the part and if there isn't anything written, the process pretty much stops there."
However, he does believe things are changing, albeit slowly. He says: "It's improving as younger engineers come into the industry. Whereas it was once brand new technology, now you're getting people who were born after the first SLA machines were installed coming into the industry. When they come through from University into design departments, they aren't stuck in the same ruts."
While he does not believe layer manufacturing will ever replace all other processes, Bennett does believe it is already finding niches as a manufacturing technology that will allow it to get "its foot in the door", pointing in particular to the way in which certain automotive companies are using ALM parts in top-of-the-range vehicles because it means not having to buy – and then amortise – the tooling for what may be only a few hundred parts.
Summarising, Bennett says: "There have been so many false dawns and over-promises in terms of the capability of the technology, but I think it's inevitable that it will become mainstream in production, though. People say to me: 'It's been 20 years!' and I have to point out that 20 years isn't really that long in this context."
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