„Flagship project“

Metalltechnik Annaberg: Producing contact parts for electrical connectors more efficiently

Metalltechnik Annaberg GmbH & Co. KG used a GRM-NC servo stamping and forming machine for the successful completion of a pioneering flagship project for the manufacture of contact parts for electrical connectors. Compared to conventional linear tool technology, Bihler’s solution achieves significantly higher production speeds of 160 parts per minute. The tools, which are compatible with the LEANTOOL interfaces, ensure vastly reduced setup times combined with simple handling.

Everything from a single supplier – that is the motto of Metalltechnik Annaberg GmbH & Co. KG, a company headquartered in Königswalde in the Erzgebirge. The service and product portfolio of this company, which was established in 1998, is correspondingly broad: “As a full-service provider in the metalworking industry, we assume full project-management responsibility, from development through to series maturity,” explains Thomas Schaarschmidt, Managing Director of Metalltechnik Annaberg. “We focus on module assembly and surface finishing and, above all, on the production of complex, high-precision stamped-and-bended parts for the electronics industry.” To manufacture these parts, the company has been using equipment from Otto Bihler Maschinenfabrik for over 20 years and now possesses a total of eight Bihler machines. “The Bihler systems stand out for their great reliability, stability and durability. They provide the precision and dynamic properties we need,” continues Schaarschmidt.

A new challenge

Grounding brackets and ground connectors play a central role in Metalltechnik Annaberg’s product portfolio. These parts are present in almost all electric plugs and sockets and ensure the reliable flow of electricity, for example in charging points for electric vehicles. The company has been manufacturing these ground connectors and grounding brackets on a GRM 80E for well over ten years. “Although the system gave us the production quality we needed, the concept and output were not optimal,” reports Thomas Schaarschmidt. “The machine only cycled at 30 strokes per minute,” adds Eric Nagel, a technology expert at Metalltechnik Annaberg. Against this background, Metalltechnik Annaberg decided to revisit the manufacturing concept for its connector components in early 2021 – in particular given that a former manufacturer was restructuring its operations and looking to outsource the production of precisely these parts. “Originally, we planned to manufacture the components using the conventional progressive tool process our partner had been using for years,” explains Schaarschmidt. However, this approach would only have achieved speeds of 60-70 strokes per minute. But our experience of Bihler technology had taught us that we could do better than that!”

Fivefold performance boost

It was clear that a project of this type could only be undertaken successfully using a new Bihler system equipped with the corresponding tools. This was the reason for choosing a GRM-NC servo stamping and bending machine. “The GRM-NC was ideal for us because it allowed us to increase our production speed more than fivefold from 30 to approximately 160 strokes per minute,” explains Nagel. To implement this forward-looking project at the machine itself, Nagel worked together with the project team, which consisted of representatives from Metalltechnik Annaberg’s Design, Toolmaking and Sales departments. Metalltechnik Annaberg entrusted the toolmaking activities to a certified Bihler LEANTOOL partner in the form of Christoph Liebers GmbH & Co. KG in Gaimersheim. The outstanding commitment of Liebers’ design and assembly specialists, who took on the challenge and rose to it expertly thanks to their many years of toolmaking experience, cannot be overemphasized. They converted a total of three tools to create autonomous modules with quick-change function that are compatible with the LEANTOOL interfaces. “The interface-compatible modules are able to run asynchronously thanks to the NC technology. This makes an enormous contribution to productivity because the slowest bending operation no longer determines the overall speed,” explains Liebers’ Managing Director, Michael Starke.

Faster, simpler, more versatile

The entire Bihler solution has been up and running at Metalltechnik Annaberg since August 2022. The manufacturing process starts with the RZV strip intake mechanism and the 40-tonne press which cuts out the contour. The strip then moves on to the thread tapping unit and optionally also to the welding unit and possibly also a second thread tapping unit. The three bending modules then perform all the necessary bending operations. An optical inspection unit then performs the final quality checks before the components are output from the line ready-for-use – at an average speed of 160 parts per minute. In addition to the enormous performance increase, the system also brings many other benefits: “On average, retooling now only takes 45 minutes and all the settings can be made at the touch of a button in just a few seconds,” says Nagel. “This makes production particularly easy and versatile.”

Unique technology

Naturally, the Bihler solution implemented by the company also surpasses the originally planned production approach using conventional linear tool technology: “The tools for a conventional progressive manufacturing system would have been extremely complex to produce and we also had doubts about the reliability of the process and the stability and dimensional precision of the components,” stresses Schaarschmidt. “The time required to harmonize the tools with the finished components was between one and three weeks,” adds Maximilian Mohaupt, Bihler Head of Sales for the North-East Region. “That just wouldn’t have been feasible using conventional progressive tooling technology.” And there is yet another benefit: “Unlike in the case of progressive tooling, you can actually look into the LEANTOOL interface-compatible modules. The component is visible throughout the entire production process, meaning that any potential anomalies or malfunctions during manufacturing can be detected and eliminated extremely quickly,” explains Starke.

New possibilities

“With this solution, we have successfully worked together to complete a genuine flagship project which will have a real impact. I’m looking forward to presenting it to our other customers,” says Schaarschmidt summing up. “We now possess a highly-productive system which will enable us to face up to the challenges of the future and open up a completely new range of possibilities.”