Stuart Mitchell has been making knives for more than three decades, cutting his teeth in the trade as a keen 10-year-old at his father’s knee. His bespoke blades are made with many of the same tools his dad used, in the same red-brick workshop his family took on in 1980.
Despite his feet being firmly rooted in tradition as a craft maker, Mitchell’s curiosity about additive manufacturing (AM) made him want to find out whether 3D printing technology could be combined with his knife making skills to create something truly beautiful and unique. This notion led to a project with the Design and Prototyping Group (DPG) at the AMRC to produce a titanium chef’s knife, a process that would demonstrate the technology and allow Mitchell to compare and contrast the end product with his own handcrafted knives.
The project is the subject of a ground-breaking exhibition called ‘Digital Mesters: Advanced Manufacturing for 21st Century Knives’ that launched on 26 September at this year’s Festival of the Mind – a collaborative festival at the university showcasing pioneering science, art, engineering and culture across Sheffield.
Design strategy manager for the DPG, Andy Bell, says: “This is design-led disruption in the truest sense; a craft maker applying advanced manufacturing technologies and exploring how this could change his business model now and in the future.
"Design methods allow us to explore, through different frames, how we approach a problem like the introduction of AM to an organisation that would never normally go near this technology due to the high perceived risk, cost and knowledge gap,” he adds. “We can use design to change perceptions by understanding the way in which small businesses work, their needs and wants, and then developing a response in a risk-free way.
“The project has been about understanding the opportunity. We provided Stuart with an AM blank that he would normally make himself from sheet metal. The difference with what we’ve done is integrating the blade and the handle, which was moulded and customised to a chef’s hand. We then delivered the printed knives to Stuart for finishing.”
Engineers at the DPG used Autodesk’s Simulation Utility for Netfabb software to aid their design and AM build optimisation work. The software was able to analyse the non-conventional support structure design thanks to its ability to simulate the influence of multiple parts on a build platform.
Luke Hill, project engineer, says: “The speed, ease of use and multi-part simulation ability of Simulation Utility for Netfabb quickly gave confidence that both knives to be printed during the build would benefit from reduced blade distortion thanks to the novel support structure.”
Mitchell, whose knives are used across the world in Michelin star restaurants and by members of the Royal family, took receipt of the AM knife at his workshop in Portland Works at the end of summer. He was struck by the quality of the piece.
“I was impressed by the profile of the blade; it replicated very well what I would do by hand, particularly the taper from the spine to the edge,” he says. “It did need a degree of grinding to apply an actual cutting edge, but the tolerances of the edge were good to start with; very fine. I didn’t realise it would print that fine.
“With the curvature and detail in the handle, the hollowed out sections – I realistically can’t do any of that,” he adds. “It’s possible but not practical because there’s probably a week or more’s worth of handwork there. The fact that all this can be added or taken away by changes to a CAD model and then adapted to suit – to increase or reduce weight – none of this I can do.
“Experience has given me a knowledge of the weight and balance of a hand-made knife, what to expect and where to aim. However, there is also almost always a ‘suck it and see’ element. I love the AM knife, it’s different and hasn’t been done before. What it perhaps also shows, particularly with all the advances in AM, is that there is still a place for what I do. An ideal product would perhaps marry the two.”
Mitchell benefitted from a grant-funding scheme run by the AMRC that is designed specifically to help SMEs fund research projects, under the Catapult SME assistance scheme.
