Thanks to this successfully completed project, the company has been able to enter the (large-scale production) e-mobility market for the first time. The machine pool of over one hundred injection-molding machines together with extensive stamping and welding equipment makes one thing clear: The core competencies of Frötek-Kunststofftechnik GmbH lie in the combined machining of plastics and metal and, in particular, in the manufacture of plastic-clad metal parts. Of crucial importance to the company are its battery cell connectors made from plastic-coated copper wires, which ensure reliable voltage distribution in the batteries of, for example, electric forklifts and other industrial trucks. Working with four fully-automated systems, Frötek manufactures approximately 15 million of these battery cell connectors every year and machines approximately 2,000t of copper in the process. However, these components are only designed for conventional lead-acid batteries – and not for the lithium-ion batteries that are found in all electric vehicles. This technology naturally represents another considerable market potential for Frötek: “To put ourselves in a position to meet market requirements in this high-growth segment, we decided to expand our product portfolio to include new components specifically intended for lithium-ion batteries,” explains Tobias Vollrath, CFO of the Frötek Group. “Thanks to our many years of experience of manufacturing cell connectors and our knowledge of copper machining, including even parts qualification, busbars were the most obvious new product for us to adopt, in particular because there is enormous demand for them on the part of customers.”

End-to-end automation
The busbars are power rails that are needed for the distribution of the electrical energy in practically all electric vehicles. “These are non-standardized components, meaning that our customers’ requirements for the initial prototypes were also very different,” reports Vollrath. Frötek produced these initial parts using a water-jet cutting system, manually operated bending machines and single-die stamping equipment. Although the sample parts and very small runs produced in this way were inefficient to manufacture, they were very much appreciated by customers – and it was not long before the first large-scale series request was received from a prestigious German carmaker. More specifically, Frötek received an order for two million busbars per year in early 2020. “Naturally, it was clear to us that there was no way we could take on this order using our previous equipment for manufacturing prototypes and that we therefore had to invest in a new production solution,” says Vollrath. From the very outset, the company excluded the option of manufacturing in multiple, separate, personnel-intensive and often error-prone individual steps, as is common with many other manufacturers: “It was vitally important to us that the new busbar manufacturing solution should map the entire production of these power rails in a single end-to-end process and consequently possess a very high degree of automation,” stresses Vollrath.

A completely new partner
These process requirements, coupled with the complexity of the components, made Otto Bihler Maschinenfabrik the almost automatic choice as a completely new partner for implementation of the project. Tobias Vollrath does not hesitate to make it clear “that the many glowing references and success stories reported by current Bihler customers, as well as Bihler’s 70-year history, were vital factors in the decision.” He goes on to say that “the manufacturing solution itself, which ran on the “Bimeric Modular”, entirely convinced us. It was extremely exciting to see the finished components leave the machine every second. Which it is why it was clear that Bihler is the right partner for us.”

30-60 busbars per minute
“At Frötek, the process begins with the RZV material feeding unit which transfers the strip to the ‘Bimeric Modular’. Here, the silhouette is stamped and the strip is transferred to the first ‘Leantool’ bending module. Another module is responsible for the laser marking of the component. The next step consists in the fully-automated, high-precision infeed of the solder plates, which are then aligned and placed on the top and bottom of the components and welded in place using the laser unit. The component is then transported to the final bending unit and punched out into its finished form. “Depending on the component, the throughput is between 30 and 60 complete, finished busbars per minute – free from any defects and in perfect quality,” explains Vollrath. A total of four different tools were developed. Thanks to the Leantool system, the average setup time is approximately 45 minutes. Final series production will start at Frötek in the near future.

Winning all round
“We were deeply impressed by Bihler’s outstanding technical expertise as well as by the extremely smooth and pleasant collaboration throughout the entire project phase,” says Vollrath summing up. “With our new busbar component, we have developed an outstanding reference product and have successfully established ourselves in the world of e-mobility. At the same time, we have, in Bihler, gained a valuable partner with whom we can successfully undertake further pioneering projects in the future.”

Otto Bihler Maschinenfabrik GmbH+Co. KG
Lechbrucker Strasse 15, 87642 Halblech/Germany
Contact person is Vinzenz Hörmann
Tel.: +49 8368 18-280
vinzenz.hoermann@bihler.de
www.bihler.de