Additively manufactured spare parts E-Bike Motors Getting a Second Life

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FAULHABER Drive Systems

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For defective e-bike components such as motors or batteries, spare parts are often not available. Therefore, they are replaced as a whole, which can be expensive. In a study conducted by Fraunhofer IPA and its partners, it was demonstrated that e-bike motors can be refurbished using 3D-printed components.

Electric bicycles made up 48% of total bicycle market sales in 2022. However, repairs by the workshop are often technically and economically unfeasible, especially for batteries and motors. This can lead to a total loss if a component of an electric bicycle fails. Researchers at the Fraunhofer IPA asked why used electric bicycle motors are not industrially refurbished. In the "AddRE-Mo" project, together with partners such as Cirp, Electric Bike Solutions, Umwelttechnologie-Cluster Bayern, and the Wuppertal Institute for Climate, Environment, Energy, they examined the technical feasibility of reconditioning electric bicycle motors.

Remanufacturing put under the microscope

According to the Fraunhofer IPA, the entire process chain of remanufacturing was examined, from non-destructive disassembly to cleaning, testing, reconditioning or replacement with new parts, and reassembly. The ecological and economic potential of the process was analyzed. In addition, the use of additive manufacturing processes and suitable combinations of processes and materials for producing durable and resilient spare parts was investigated. The goal was to establish an industrial process in which a quantity of 50 to 100 motors goes through the reconditioning process.

3D printing of wear-prone spare parts

In the first step, the researchers examined the failure probability of e-bike motors from established manufacturers. They then investigated whether and under what conditions wear-prone spare parts such as gears and torque supports could be additively manufactured. The necessary data for 3D printing was obtained by either 3D modeling or 3D digitization. Subsequently, they selected materials and additive processes. Together with the companies cirp and Electric Bike Solutions, Fraunhofer IPA finally manufactured the components and tested their service life, noise development, and temperature resistance in specially developed test rigs and under real conditions. In total, over 120 components made from 20 different materials were produced using 3D printing. According to Fraunhofer IPA, the Highspeed Sintering process, a special method for manufacturing or modifying materials, in combination with the plastic Polyamide 12 (PA12), proved to be particularly promising.

Prove feasibility and durability

With the remanufacturing and testing under real operating conditions, the project partners were able to demonstrate the technical feasibility and durability. The research results show that individual components such as gear wheels can be additively manufactured and sustainably used. According to Fraunhofer IPA, the ecological evaluation of the remanufacturing process indicates that additive manufacturing has the potential to increase the circularity in the e-bike industry and reduce resource waste. Compared to new production, 90 percent of the climate impact, calculated in kilograms of CO2 equivalent, could be saved. The economic saving potential, on the other hand, depends on the number of units and is typically around 30 to 40 percent for comparable components compared to purchasing a new electric motor.

The project results are summarized in the study "Additive remanufacturing in the electric bicycle industry". It can be ordered here.