Manual assembly has its advantages: No machine solution, however sophisticated, is as universally applicable as the human hand, and no automatic assembly process is as flexible as experienced fitters. But when demand increases, this approach reaches its limits. The company ABL - a specialist in high-quality charging solutions for electric vehicles - has decided to take a new approach: with the support of the Bott Group and its expertise in assembly lines and software, a digitalized production facility has been created that combines manual and automated processes. From picking the individual parts to preparing the finished products for dispatch, all work steps were to be traceable in detail. The result was reliably plannable productivity, needs-based scalability and a performance potential that allows wallbox production in 30-second cycles.

ABL's need arose from the newly developed eM4 wallbox. With this product, the company has positioned itself in the premium segment of commercial charging stations. The system therefore had to meet high quality testing requirements and offer scalable throughput as well as the flexibility to efficiently produce different product variants. The distinctive design of the wallboxes and their calibration certification also required individually adapted assembly steps. The development of these specifications was essential for the start of the detailed planning.

Product and production in harmony

An assembly line like the one that was to be created for ABL is a custom-made product. "While we were planning the production line, the Wallbox eM4 was also still under development," recalls Rösinger. This was a stroke of luck, as it meant that the design of the product and production could be mutually coordinated. "Even small adjustments to the product can significantly simplify an assembly process," says Rösinger. "For example, a slightly repositioned screw connection can prevent the entire workpiece from having to be rotated 180 degrees."

Automated cells were planned as quality gates for the associated test concept - both for the inline and end-of-line tests. Among other things, the test routines were to visually check the cabling, as well as aspects relevant to safety and calibration law. The final test turned out to be a masterpiece: the task was to simulate, verify and fully document all of the wallboxes' statuses in a sophisticated process.

"We also took measures to keep the manual work error-free," recalls Rösinger, referring to special assembly devices based on the poka-yoke principle and easy-to-understand step-by-step work instructions using Bott's own assistance system. Work efficiency and ergonomics were also run through manually in extensive workshops. "It's important to scrutinize every process," says Rösinger. He remembers a situation in which a move suggested in the workshop seemed obvious - but then it became apparent that the person who came up with the idea was left-handed. "Little things like that can have a big impact on day-to-day production later on," says Rösinger. "And they underline once again the importance of joint considerations and communication."

From concept to reality

The hall-filling system was implemented in several stages. On the one hand, this allowed ABL to launch the first series products on the market as early as possible. On the other hand, the concepts developed could be tested in practice and, if necessary, adapted in a subsequent step. In coordination with the customer's IT department, the production software developed by the Bott Group was connected to the ERP system. This forms the heart of the system, sets the pace and controls all connected components.

With the overall solution, ABL is able to scale its output according to demand, plan precisely and derive valuable production data. The modularity of the system also facilitates future modifications - whether due to new product developments or changing market conditions. And the Bott Group also benefits in the long term: with the features developed specifically for this project, it is even better positioned to help other customers with similar challenges.