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Is 3D printing cycling's next big thing?

James Spender
25 May 2016

Self-replicating printers creating objects from computer drawings? Not science fiction, but a reality set to revolutionise manufacturing.

Although you might not think it, 1986 was a pivotal year. The deregulation of the London Stock Exchange changed the way we thought about money; Chernobyl changed the way we thought about nuclear power; Top Gun changed the way we thought about movie soundtracks, and, for those paying careful attention, an American gentleman by the name of Chuck Hull changed the way we thought about manufacture.

That year on 11th March (perhaps appositely one million days since the traditional founding of Rome), Hull was issued with US patent number 4,575,330: ‘Apparatus for Production of Three-Dimensional Objects by Stereolithography’. And so the 3D printer was born.

‘Chuck Hull was the guy that started it all,’ says Phil Kilburn, sales manager at 3D printing company 3T RPD. ‘He was working for Xerox at the time, and came up with the idea of laying inks on top of each other to create a solid three-dimensional model. He took this process and started the first 3D printing company, 3D Systems.’

In the beginning

Hull’s original 3D printer used an ultraviolet light to draw a two-dimensional shape over the surface of a vat of liquid photopolymer, a substance that turns solid when exposed to ultra-violet rays. This process happens over and over again, building up 2D layers to create a 3D object. While the processes and materials used in 3D printers have come a long way since then, the rudiments remain the same.

‘The machines we use now employ lasers,’ says 3T RPD’s IT manager Martyn Harris. ‘The process is extremely clever, but in its basic form it’s very simple: take some powder and melt it. So in our machines you have a bed of powdered material, for example nylon, which is heated up in the printer’s chamber to just below its melting point. Lasers then trace two-dimensional cross sections of the component you wish to produce over the powder, melting a 2D layer each time. Once a layer is traced, the bed of the printer drops down by, let’s say, 120 microns [0.12mm], then a re-coater arm spreads another layer of powdered material over the top and the process begins again, with the lasers tracing out the next layer.’

This process is predicated on the method of ‘sintering’, where at high temperatures the atoms in a powder’s particles diffuse into each other and become a solid piece. But it’s not enough to just aim a laser at some plastic and expect a useful object to emerge.

‘What you do first is make a 3D CAD [computer-aided design] model of what you want to make,’ Harris says. ‘Then, using bespoke software, you pack the models into a virtual 3D space that mirrors the size of the printer bed. From there you save all your files in STL – stereolithography, or triangulated files – and when you’ve got the files ready you basically slice them all into whatever thickness you’re building. All of those sliced files get sent to the computer that controls the printer and then it’s just a case of pressing go, and the printer will print it. Ironically, a lot of the parts of these printers are printed on other printers here, so they’ve become self-repeating.’

Harris has been involved with 3T RPD for the past 13 years and, most recently, has founded Race Ware, a bicycle component company that manufactures its products – from plastic Garmin mounts to titanium chain catchers – using 3T RPD’s printers.

‘I got into this because I run an SRM and have a pair of Easton TT bars,’ says Harris. ‘When I went to look for a bar mount, all I could find was some horrible adaptor kit, so I thought I’d make my own. I figured that if I was making one for me, I’d see if anyone else wanted one too, so I went onto a TT forum and asked around. This guy called Jason Swann said he wanted a Garmin one, and he was a CAD designer so he gave me the design. It only took us three or four months to get from the first iteration to the version we’re now selling.’ 

As Harris indicates, one of the key advances that comes with 3D manufacture is the speed and ease at which products can be produced and honed. The overall process from drawing board to finished article is exceptionally fast compared to more traditional methods – although build times can take anything from a few hours to around a week, depending on the complexity and number of the products being printed.

‘Unlike other manufacturing processes, such as injection moulding, with 3D printing there’s no tooling,’ says Harris. ‘All I need to do is create the CAD model, do a few test runs, make a few tweaks and then when I’m happy with it, start printing. People find it hard to get their heads around it. They ask what the lead time is and I can reply, “Two or three weeks,” whereas they’re used to someone saying, “It’ll be ready by quarter four of next year.”’

Rapid prototyping

Of course 3T RPD and Race Ware aren’t alone; there are other manufacturers and industries currently reaping the benefits of 3D printing and looking to push the boundaries ever further. Audi used 3D printing robots to create the RSQ concept car that appeared in the film I, Robot; Formula One teams such as Sauber use 3D printed brake ducts on their cars, and, most recently, Dutch architect firm Dus Architects announced plans to 3D print an entire house. So, if all this is feasible (the house will allegedly be built in parts on a six-metre high printer named the ‘KarmerMaker’), what might the implications for bikes themselves be? One man who thinks he knows is head of research and development at Ridley bikes, Dirk Van den Berk.

‘We’ve been printing small prototype components for the last two or three years, like the brake for the Noah Fast fork,’ Van den Berk says. ‘But for the first time this year [2013] we’ve printed a whole frame as part of the development of our new version of the Dean TT bike. It’s not strong enough to be ridden or stress tested, but it’s great for aero testing in the wind-tunnel and assembly testing, where we can build it up with real components to see that everything fits.’

As with Race Ware, this particular type of 3D printing – known as rapid prototyping – allows Ridley to make changes quickly and cheaply. ‘The Dean started with tube shapes to test in the tunnel. Then we built complete frames. We test these, evaluate, then go back and make small changes. That’s the great thing – small changes can be made very fast. You just have to push a button and wait for the printer to stop printing.

‘Previously you would use computers and software to create a frame, up to the point where you give the green light and the frame makers start cutting the moulds. While 3D printing isn’t cheap technology, it’s certainly cheaper than opening a mould, seeing something wrong with the frame and having to start over,’ Van de Berk adds.

So, if companies such as 3T RPD can print in metal and manufacturers such as Ridley are already printing whole prototype bike frames, why can’t we put the two together and start printing rideable bikes?

‘For a complete frame it’s quite difficult because of the way a frame is loaded during riding,’ Van den Berk explains. ‘It’s a complex structure that needs to be able to deal with all kinds of stresses and strains. With carbon, the way you create the layers is what makes a frame strong or stiff in a certain direction. With printing it’s much more difficult to control the properties of
the material and that’s what makes frame production hard. However, things are certainly going in that direction.’

Economies of scale

Back over the Channel in Bristol, there’s one company for which the reality of 3D printed frames is getting ever closer – at least in part.

Charge Bikes has been working with EADS (European Aeronautic Defence and Space Company) to create the first production-printed dropouts. Made from Ti6Al4V titanium, the dropouts are printed at EADS’s facility before being shipped over to Taiwan to be welded into Charge’s freezer cross bikes. However, while EN testing and a gruelling eight months under Charge pro rider Chris Metcalfe have shown the dropouts to be every bit as successful as their CNC’d cousins, they, and the process they are part of, are not without limitations. 

Charge’s Neil Cousins says, ‘Currently the printed dropouts add 20% to the cost of a standard Freezer frame, in part because each build can only produce a maximum of 50 dropouts due to the size of the printer. We’re also constrained with the number of printers out there – currently only three other companies in the UK have them – and the expertise and skills needed to use them.’

Cousins points out that there’s no reason why in the future the cost of producing such parts can’t come down as machine sizes and numbers increase, but for the time being he’s realistic about where the technology’s headed: ‘We are always coming up with plans for parts and have just hired a new industrial designer here. One thing to remember is that a lot of the parts will be so expensive that we have to be careful not to do something that will sit on our distributors’ shelves for years. That said, a lot of the big players in the bike industry have been in touch with us and EADS to get more information on the technology, and in the shorter term I can easily see 3D printing being used for making components such as hubs, mechs and cassettes.’

Race Ware’s Martyn Harris may well be one step ahead, having collaborated with aerodynamic guru Simon Smart to make a titanium stem. While far from being a finished, saleable item (Harris estimates that the current version has cost him £5,000, so shifting one could be a little difficult), it just serves to prove what level 3D printing is currently at, and also what it’s going to take to get to where companies such as Race Ware and Charge would like to go.

‘The key to 3D printing’s future is understanding the process,’ says 3T RPD’s Phil Kilburn. ‘It’s taken a lot of missionary work on our part to get people to believe in the technology, to educate people as to what it can and can’t do. Only once you’ve understood the process can you then take advantage of it. It hasn’t quite got there yet, but when it does, 3D printing’s going to explode.’

The fine print: How 3D printing actually works

  • As well as building in plastic, 3T RPD has a series of machines that print metal parts, such as these titanium chain catchers commissioned by Race Ware.
  • The printer chamber is heated to 70°C, before a single fibre laser, operating at 1,000°C+, traces out the two dimensional layers in a bed of titanium powder.
  • The bright white light you can see isn’t the dot of the laser, but rather an intense light that’s emitted as the powdered titanium becomes molten. 
  • The chain catchers are built in 20-micron layers – after each layer has been traced out, the printer bed drops by 0.02mm before a fresh layer of powder is spread out.
  • Metal printer beds tend to be much smaller than plastic printer beds. But the latest of 3T RPD’s machines already build 50% higher than their predecessors.
  • The big issue with making printers bigger comes with focusing lasers. The smaller metal printers use a single laser, whereas the larger area plastic printers must use two.
  • Printing three chain catchers in titanium takes around four hours. Up to 50 can be squeezed into the printer bed, but the build time will increase to around 12 hours.
  • When the build is finished, the parts can be removed almost like retrieving a stone from a pile of sand. Much of the left-over powder is recycled and put back into the next build.

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