More and more people are using electric bicycles. But if something breaks on the motor of such an e-bike, there are often no spare parts – the entire e-bike motor is replaced. But there is another way, as a research project has now proven: You can use 3D printing to produce spare parts for engine components that are hardly inferior to the originals and which make the old e-bike engine look like new. This “remanufacturing” saves raw materials, energy and money and also promotes the circular economy for electric bicycles.
The trend towards e-bikes is unbroken: According to the German Bicycle Industry Association, by 2022 bicycles equipped with an electric motor accounted for 48 percent of all new bicycle purchases – and the trend is rising. But if something breaks on the e-bikes, repairs by the workshop, especially for batteries and motors, are often technically and economically unfeasible. It can be the case that the failure of a component of an e-bike can lead to a total loss.
Spare part instead of new purchase
“If the motor or the battery fails, the entire component is usually replaced, although it is possible that only one gear is defective. Repairs are often not worthwhile for e-bike workshops, and manufacturers are also very interested in replacing old motors, which are the biggest cost driver for e-bikes, with new ones,” says Jan Koller, project manager and group leader at Fraunhofer IPA , the dilemma. “Our goal was to implement a value preservation network by establishing an industrial process with remanufacturing in which a larger number of 50 to 100 engines go into the refurbishment process.”
In the “AddRE-Mo” project, Koller and his team have now examined the technical feasibility of remanufacturing electric bicycle motors with other partners. In the first step, they tested electric bicycle motors from established manufacturers for their probability of failure. They then investigated whether and under what conditions spare parts with a high wear rate, such as gears and torque arms, can be produced using 3D printers. A total of over 120 components made of 20 different materials were produced using the 3D printer. The Fraunhofer IPA team then tested the service life, noise level and temperature resistance of the spare parts and e-bike motors produced in this way on specially developed test benches and under real loads.
Good for the environment and your wallet
The tests showed that individual components of defective e-bike motors can be reproduced using 3D printing and they are stable and durable enough to be used again in the motor. The production method of high-speed sintering, a special process for manufacturing or modifying materials in combination with the plastic polyamide 12 (PA12), proved to be particularly promising. After reassembly, these components, including, for example, transmission gears, also passed the test under real operating conditions. “At the end of the process chain, remanufacturing gives you a bicycle engine that corresponds to a newly manufactured engine in terms of quality and also includes the same guarantee,” says Koller.
According to the scientists, this remanufacturing offers an opportunity to reduce the consumption of raw materials and energy for electric bicycles. “Additive manufacturing offers the potential to increase circularity in the electric bike industry and reduce waste of resources. 90 percent of the effects on the climate, calculated in kilogram CO2 equivalents, can be saved compared to new production,” reports Koller. Whether this reproduction of spare parts and their installation is also financially worthwhile depends on the number of pieces: the more such spare parts are produced, the cheaper it is. On average, the scientists put the economic savings potential at around 30 to 40 percent compared to buying a new electric motor. As a result, remanufacturing also offers great potential for the manufacturers of electric motors.
In order to bring companies closer to the possibilities and the practical implementation of remanufacturing, the Fraunhofer IPA initiated the “RemanLab”, a kind of learning factory in which knowledge about the remanufacturing process from incoming inspection to disassembly, cleaning, testing, refurbishment, reassembly and Final inspection is conveyed on the specific object. “Until now, remanufacturing was characterized by costly and labor-intensive processes. In the RemanLab we show how digital technologies and automation can revolutionize the remanufacturing not only of electric motors, but also of small electrical appliances and other products in the future,” says Koller.
Source: Fraunhofer Society