Bicycles from the 3D printer - a dream?
Bike buying 2.0: If you want a new racing bike, you go to a bike fitter. They take all the relevant body measurements and send the data to the local production centre. The bike - frame, handlebars, saddle and several other parts - is produced there and is ready for collection two weeks later. Printed from titanium and plastics. Lightweight, corrosion-resistant, durable, almost completely recyclable and no more expensive than current carbon bikes. A dream? Not yet. But some of it is already a reality.
At the Eurobike trade fair in Frankfurt in June, Dutch manufacturer Pilot Cycles presented "Seiren" - the prototype of a racing bike printed and bonded from three titanium parts. The Eindhoven-based company has been custom-welding conventional titanium frames for ten years. The latest plant is the first frame in which the tubes are also printed, and series production is due to start at the end of the year. Initially, the frame heights 54 and 56 with standard geometry will be offered. Equipped with high-quality components, the price is expected to be around 16,000 euros. Customised geometries are to follow.
Bastion, an Australian manufacturer, prints titanium sleeves and glues carbon tubes into them. The Australians were inspired by the thesis of German Ralf Holleis, who was the first to use this process (see interview below). Bastion claims to be able to print a set of muffles in two days. The resulting bikes are customised and cost around 17,000 euros. The bikes from Sturdy Cycles in England are also in comparable regions. Unlike Bastion, they are made entirely of titanium.
Tom Sturdy, an aeronautical engineer, lives his dream of a customised bike like no other and welds the tubes into titanium sleeves. Sturdy also prints cranks, handlebars and small parts and uses anodising to give all products a robust and special aesthetic. He is a developer, bike fitter and manufacturer all in one. Nevertheless, Sturdy is fast. The time from order to delivery of a customised bike is currently only around three months. At Bastion, on the other hand, interested parties have to calculate with a lead time of at least one year.
3D printing is (still) expensive
When we talk about printing objects (see below), two technical approaches can be considered for this, roughly simplified: The melting or welding of a usually powdery starting material is the usual process for metallic objects. Plastic is applied using a nozzle.
Printing metal is expensive - especially printing large parts. Johannes Thumm, an engineer in Canyon's Innovation Lab, reports that at a recent trade fair, a service provider offered to print titanium frames in one piece - for 15,000 euros per piece. A price that might be paid for rocket parts, but certainly not for a bicycle frame. Nevertheless, Canyon is intensively researching the topic of 3D printing titanium, says Thumm: "We were actually thinking about natural fibre composites at first, but after the positive response to a printed aluminium frame in 2021, we looked into titanium because a real material cycle can be realised with it."
The highlight here is a partnership with the young US company Iperionx, which wants to mine titanium using new processes that are much more cost-effective and environmentally friendly - in Tennessee in the USA. Titanium is a metal that is actually common but has been difficult to extract until now. Iperionx has also developed a process to recycle the metal with comparatively little energy input, which was previously not possible. On this basis, Iperionx is pursuing the vision of using titanium as a sustainable metal in more versatile ways than previously possible, not only for aerospace and medical technology - but also for the automotive industry and everyday objects.
Titanium could compete with carbon
Whether the plan will work out is still uncertain. Iperionx launched on the Nasdaq technology exchange in 2022, but the processes are all still at the trial stage. The annual report points out that investing money in the idea can be risky. However, if what the company announces comes true, titanium could compete with carbon. It will probably not be possible to achieve the low weight of optimised CFRP frames with the metal, but many other advantages would be possible with it, in particular local production and a friendlier ecological balance.
Pilot Cycles stated the weight of the prototype at 1150 grams, with the next version set to be another 100 grams lighter. That would be very light for titanium, but still 350 grams heavier than is currently possible with carbon. Race victories can already be achieved on a printed bike. Italian professional cyclist Filippo Ganna raced to the world hour record with the Pinarello Bolide F HR 3D-C, made from three printed aluminium parts bonded together.
The customised cockpit, which supported Ganna and directed the airflow at the same time, is printed from titanium. The process gave the engineers the freedom to test the aerodynamic quality of different versions of the bike much faster than with carbon and to customise the bike to the athlete. Since no mould construction is necessary, the step from design to wheel is drastically shorter and cheaper than with carbon.
Customisation for the masses thanks to 3D printing
However, not only frames and frame parts are printed. Printed saddles, for example, are currently more widespread and several major manufacturers have them in their programme. Posedla from the Czech Republic is currently the only supplier to produce customised saddles based on a seat print. Cost: 490 euros, backed by a money-back guarantee if the saddle is not to your liking.
The English manufacturer Metron, which was involved in the construction of Pinarello's world hour record bike, sells stems and track handlebars under the Mythos label. Printed add-on parts are available from 4-frames.de, which can be used to add aerodynamically optimised storage space to Canyon time trial bikes. Small parts such as race number holders can also be purchased via the web shop.
The technology of printing objects has therefore arrived in the world of bicycles, as well as in other areas of industry where spare parts, prototypes and even small series are already a reality. The power of printing is particularly evident in aviation, as complex structures of engine parts can be combined into one printable part, thereby reducing their weight.
According to the experts, printing will not be a brief foray into the adventure of what is feasible, rather the opposite. In the long term, it is conceivable that customers will purchase data for the subsequent printing of spare parts when they buy machines, says plastics printing expert Jens Kruse from the Institute for Integrated Production in Hanover. This would also contribute to greater sustainability and, in the case of bicycles, could involve parts such as covers or panelling for current aero racing bikes.
Even vintage fans can revive old parts true to the original. Service providers such as Scanmotion scan components and develop print data from them. Whether this still has anything to do with vintage and the idea of preserving historic bikes is something that can be philosophised about at the regulars' table. The fact is that the power of data has also reached the realm of bicycle manufacturing.
Printing facts
That's what it's all about
In principle, the printing of materials is comparable to a hot glue gun, which is guided by a machine, creating the printed body layer by layer. In contrast to conventional (metal construction) processes such as milling, only the material that is actually required is used. Hollow bodies can be reinforced on the inside with mesh or grid structures, and wall thicknesses can be adapted to the loads at specific points.
Which materials can be printed?
Almost all of them. Concrete, ceramics, steel, aluminium, titanium, a wide range of hard and soft plastics and even fibre reinforcements through to continuous carbon fibre for highly stressed plastic parts.
What procedures are available?
A rough distinction can be made between processes that work with powders - which is the common process for printing metal - and those in which the material is applied via a nozzle, the common plastic printing process.
Fused Filament Fabrication (FFF)
This process works with so-called filaments, which are plastic wires of various types that are unwound from drums and processed via a nozzle. A wide variety of plastics are available, including carbon fibre-reinforced nylon. Printing takes place on a heated carrier plate, from which the object is later removed. Industrial FFF printers cost from 10,000 euros.
Selective Laser Melting (SLM)
In this powder-bed-based melting process, a super-thin layer of metal powder is applied to the build plate, one or more lasers weld the powder with absolute precision, followed by the next layer and so on. At the end, the finished body is buried under unused powder, which is extracted and reused.
The body is finished after printing. Zones with very small tolerances, such as bearing seats, are reworked. There are also machine tools that combine both techniques, FFF and SLM. The technology is expensive, laser printers cost from 100,000 euros, and the size of the printable parts is limited. Typical construction spaces are only 30 x 20 x 20 centimetres, which is why bicycle frames cannot be printed in one piece.
Do it yourself
An FFF printer that processes plastic is available from around 300 euros. The installation space in which the product can be created is relatively small; if it is utilised, the printer can run for two days or longer. Small parts such as holders for computers, lamps or start numbers can be printed without any problems, but really solid and weight-optimised components are not. Printing a stem or a crank is much more complicated and expensive. Metal laser printers for heavy-duty parts are really expensive and not for home use.
Metal printing at home
However, metal objects can also be produced more cost-effectively in plastic printers with hardened nozzles via a diversion. Powdered metal is bound in plastics for this purpose.
The plastic-metal composite is processed through nozzles, with the printer initially only melting the plastic. The blank must then be washed in a solution, after which the whole thing is placed in a sintering oven, where plastic burns at very high temperatures and the metal components fuse together.
The body shrinks by around 20 per cent of its original size, which must be taken into account in the design. Post-processing is offered by service providers. The method is primarily intended for small parts up to a maximum of 100 x 100 x 100 millimetres.
Construction
Designing comes before printing. Print data for many simple objects can be found on the internet on exchange platforms. You can even download the data for printing an MTB frame in one piece.
If you want to design yourself, you need CAD software to create a model and generate print data. You can start with free CAD software such as Tinkercad. For non-commercial purposes, even sophisticated professional programmes such as Onshape are available free of charge - but the designs created in this way are then freely available.
These manufacturers print frame parts:
- athertonbikes.com
- bastioncycles.com
- falkenjagd-bikes.de
- huhncycles.com
- pilotcycles.com
- sturdycycles.co.uk
- urwahn.com
Bicycles from the 3D printer - Interview
Ralf Holleis, owner of Huhn Cycles, is a pioneer in the 3D printing of bicycles
The Interview was led by Robert Kühnen
TOUR: On a scale of one to ten, how crazy do you have to be to use 3D printing on a bike?
Ralf Holleis: I was the first in 2011, back then it was still very crazy, I would say eight to nine. In the meantime, the marketing work has been done and there is confidence in printing. Today, it's still crazy in financial terms at most.
TOUR: How did you come to use 3D printing for bicycles?
Ralf Holleis: I really wanted to build a frame, that was my dream during my studies. But I didn't have the money to attend a frame building course. Then an opportunity arose: a 3D printing start-up was set up in the village next door. They printed the lugs for my first bike, which I developed as part of my thesis, for free. That was my springboard. At the time, the topic of the thesis was also adapting the bike to the human body. I developed a programme that could automatically adapt the design data.
TOUR: Why was your first bike a track bike?
Ralf Holleis: I was young and a student, and fixies were hip. Back then, people rode fixies in the city. A fixie is also the most banal bike you can build - no brake mounts, just nothing. I also wanted to build a lightweight bike. The fixie came in at 4.9 kilos.
TOUR: Why did you glue the first frame?
Ralf Holleis: I wasn't familiar with the trade at first, so I glued the pipes to the sockets.
TOUR: You have retained the construction method; what is the advantage over butt-welded titanium?
Ralf Holleis: The parts are more intelligent. I can integrate cable guides, threaded holes and internal support structures. I can optimise the flow of forces via the shape of the parts and the wall thicknesses. And sockets save the frame builder a lot of time. It takes a few hours to produce nodes such as the seat node by machining the tubes. This is much quicker with the sleeves. Printed dropouts also save a lot of time.
TOUR: How much does a kilo of titanium print cost?
Ralf Holleis: This is difficult to quantify. It depends on the support structure, the number of lasers in the machine and the necessary reworking. The trend is towards small series. A set of moulds for a bicycle on a build plate is no longer of interest today, as it is expensive and time-consuming. With printers with four lasers, as they are currently used, the capacity utilisation is better if I print the same part four times. A kilo of titanium print costs between 2000 and 4000 euros.
