8. December 2020
The importance of 3D printing in bicycle development
The possibilities surrounding 3D printing are experiencing a real hype. In the meantime, even hobby tinkerers are using small, compact devices to implement their creative ideas three-dimensionally. For several years, 3D printing has also taken a firm place in ROTWILD's engineering and is becoming increasingly important in the design phase of new bikes.
How does ROTWILD use 3D printing in engineering?
In the development process of a ROTWILD bike, a large number of 3D-printed parts are created, starting from the design on the screen to the finished model. Each mold and each component go through their own extensive development phase in conjunction with the overall design. Here, the production of individual parts in 3D printing serves primarily to check the project.
Even in early development phases, 3D models can be transferred from the computer to real components.
Advantages of 3D printing process
The development of a new bike is costly and complex. It often takes more than two years from the initial idea to the final product ready for series production. During this time, individual design steps have to be checked again and again. 3D printing is an efficient and fast tool for this. The technology of 3D printing offers two major advantages here:
- The single piece production or the production of small series saves mold and tool making as well as the time-consuming programming of CNC machines.
- The implementation of complex structures works quickly and only little material has to be used.
In addition to the design on the computer, 3D printing can be used to analyze dimensions, installation spaces and possible design problems even before the frame is built in the time-consuming and cost-intensive mold construction process. Necessary changes are thus identified at an early stage and incorporated into the design accordingly.
Development engineer Christoph Scheuvens explains: "It makes a big difference whether I only see a design on the screen or whether I have the opportunity to build a real frame in its original size - even if it is still made of plastic - to create a complete wheel. This gives me a completely different impression of the final product, we see the form factor and the design in the right scale. This 1:1 model building is possible at an early stage of development."
The new Quick Release battery for the IPU375 was also created in advance in several iteration steps using 3D printing.
How does the process work?
Powerful software tools are permanent and indispensable companions in the development process. Starting from the three-dimensional CAD design drawing, an additional document is created that precisely defines the so-called functional surfaces, such as thread diameters. Subsequently, the material from which the printed 3D model is created must be selected. ROTWILD Engineering works intensively here with the specialists of the Fa. Sauer Product together. There, the final component file is broken down into individual layer information, imported to the corresponding machine and the printing process is started. Depending on the intended use, the final post-processing is carried out up to and including painting.
Only with know-how and EDP support does the setting of the data and the transfer to the 3D laser printer work for the desired result.
Innovative process metal printing
Metal printing is an innovative process for manufacturing metallic workpieces that has only been available for a few years. As with conventional machining processes (CNC), the component is built up directly from the 3D CAD data. The difference to the CNC process is that the component is not machined out of a block, but is created or grows out of nothing, so to speak.
The laser works out the final component layer by layer. This process takes several hours, but the end result is a functional and resilient component.
In this process, metals are melted in powder form by a high-energy laser beam with high energy density. The components are built up layer by layer. After each laser pass, the plate with the metal powder moves down one step and the metal powder is evenly redistributed. This process repeats itself until the complete component is finished.
The density of the components produced in this process approximates the base material and thus also its mechanical properties - it is therefore not a porous material. In the chassis and geometry development of the first R.E375 prototypes, ROTWILD Engineering deliberately opted for this form of 3D printing.
Fresh from the printer, however, before it is used in the prototype bike, extensive finishing work and several control runs are carried out.
Extensive prototype testing thanks to 3D printing
The use of 3D metal printing provided a decisive advantage, especially in the prototype phase of the R.E375: because months before the first new Shimano EP8 motors were even available, we were able to complete intensive test runs in the field under real conditions.
For this purpose, our engineers produced a special bottom bracket design in 3D printing, which was installed in the frame instead of the motor. This meant that the prototype of the new R.E375 was fully operational even without the e-drive. This allowed us to complete numerous test rides on the trails over the course of an entire year and check in practice whether the chassis and geometry fit the planned range of use. Before the bike finally went into production, it was the use of 3D metal printing that enabled optimal fine-tuning of the handling characteristics.
Placeholder: Instead of the new Shimano EP8 motor sits here the specially developed bottom bracket construction for mounting cranks and drive.
This example shows that the production time for roadworthy prototypes can be reduced enormously with the help of 3D printing technology. This means that there is more time before series production to extensively test new bike concepts and optimize them in such a way that real innovations bring noticeable improvements in bike performance.
Thanks to 3D printing, numerous intensive driving tests with this first prototype of the R.E375 on our local trails were possible even without an engine.