INTRODUCTION
In the context of electric mobility, where each component directly influences efficiency, performance and safety, the development of technical solutions requires a highly specialised approach. This case study presents the design and production process of a functional aluminium part designed for electric bicycles – a technical support for a cadence sensor, used by the electric motor management system to constantly optimise the level of electrical assistance to the rider and simultaneously maximise battery life. ETMA was selected as a strategic partner for its ability to integrate multiple production processes and its accumulated expertise in high-precision metal solutions.
TECHNICAL CHALLENGE: DIMENSIONAL ACCURACY AND FUNCTIONALITY
The part concerned, stamped from aluminium, fulfils a critical function: ensuring the precise positioning of a sensor, which is responsible for monitoring and transmitting data regarding the motor’s energy consumption. The technical requirement was clear: combine structural lightness with rigorous geometric precision.
From the budgeting phase, ETMA actively participated in the feasibility analysis of the design proposals presented by the client. Some initial geometries featured cuts and tears in areas that, according to ETMA technical team’s assessment, would compromise the dimensional stability of this part during stamping and folding phases. Based on this analysis, recommendations for construction optimisation were made, resulting in a technically feasible and functional design.
SOLUTION IMPLEMENTED: INTEGRATED ENGINEERING BASED ON ETMA’S PRODUCTION PROCESSES
The project involved close cooperation with the client throughout the entire development cycle, from the co-engineering phase to the industrialisation of the product. The part is currently mass-produced, with annual volumes estimated at approximately 100,000 units, and involves the following processes:
During the development phase, ETMA cooperated with the client to analyse different construction proposals, ensuring the technical and productive feasibility of the part from the beginning.
Prototypes with optimised geometries were produced and tested by the client’s technical team for validation, taking into account the intended performance and compliance with dimensional and tolerance requirements. This phase was crucial to stabilise the final design, simultaneously ensuring the sensor’s functionality and ease of mass production.
Based on the validated final design, ETMA developed the stamping tool in-house, custom-designed to meet the specifications of the part and the behaviour of aluminium in operation.
The in-house construction of the tool ensures not only the desired dimensional accuracy, but also the durability required for annual production volumes, which, as mentioned above, are around 100,000 units.
Mass production is carried out by stamping in a 105-ton press, a process tailored to the part’s geometry and the specified aluminium alloy (AW 5754), 2.5 mm thick.
Additionally, the part includes folding operations at critical angles, executed with high precision to ensure correct sensor integration and reliable operation.
The entire process is optimised to ensure repeatability, quality, and productivity.
Although aluminium is naturally corrosion-resistant, the part is finished with a cataphoresis coating (KTL coating, RAL 9004), mainly to ensure a discreet appearance within the bicycle assembly.
This process is performed by a certified partner from ETMA’s supplier network, whose selection, validation and monitoring are fully managed by the ETMA team.
This partnership model ensures that the finishes comply with the defined quality standards.
In the final phase of the production process, a PEM nut (M3) is inserted, a metal component supplied by a specialised manufacturer, whose integration was ensured by ETMA.
This operation is carried out rigorously, respecting the defined tolerances, to ensure the mechanical functionality of the part.
Construction alternatives that would eliminate the need for assembly were also presented, reinforcing ETMA’s commitment to continuous improvement and process simplification.
The part undergoes rigorous dimensional inspection, supported by functional templates developed by ETMA, together with the client.
These devices allow for validation on the production line that the geometry of the part meets the assembly and final operation requirements of the sensor.
This process ensures continuous quality control and the traceability necessary for mass production.
The integrated management of these processes demonstrates ETMA’s ability to ensure traceability and quality control throughout the entire value chain, providing complete industrial solutions that are optimised and tailored to performance, time and cost demands, even when including production phases outside its facilities.
RESULTS ACHIEVED: A CUSTOMISED SOLUTION, WITH PERFORMANCE AND EFFICIENCY
The result is a technically demanding part, designed based on collaborative engineering principles, which combines:
- Dimensional accuracy, essential for the sensor’s proper operation.
- Structural lightness, in line with the requirements of electric mobility.
- Functional aesthetics, through quality finishing.
- Optimised production process, with controlled production costs.
- Reliability in mass production, ensured by a continuous dimensional and quality control system.
ETMA even proposed an alternative solution to assembling the nut, integrating it into the body of the part, which would eliminate an assembly phase and reduce complexity. Although the option was not implemented, its presentation reinforces ETMA’s role as a partner with a vision of industrial efficiency.
CONCLUSION: TECHNICAL COMPETENCE AND STRATEGIC PARTNERSHIP
This project reflects ETMA’s approach to applied engineering – a combination of technical expertise, integrated process management and focus on the client’s needs. By providing a production system that integrates 10 internal processes and a network of qualified partners, ETMA ensures complete, tailored and sustainable solutions.
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