The proportion of automated processes in control cabinet construction is still low – but that is set to change. The Siemens plant for combination technology in Chemnitz (Siemens WKC for short) is leading the way: A combination of digital twin and AI-based systems is to greatly increase the automation share in control cabinet production over the next ten years – all the way to autonomous assembly processes.

To be equipped for the production of the future, sustainable and resource-efficient production is needed, as well as a high degree of flexibility combined with high productivity. Producing companies must rely on future-proof technologies and rethink their current production processes to remain competitive and strengthen their position on the market. Of crucial importance against this background is the vision of “Engineering to Zero”: It is based on the use of autonomous machines such as driverless transport systems or independently acting robots. The goal: fully automated and customer-oriented production.

Automation for batch size 1

Siemens WKC is one of Europe’s leading suppliers of electrical switchgear and manufactures for a wide variety of customers in mechanical and plant engineering. Thomas Puschmann, group manager at Siemens WKC, explains the plant’s main area of business: “The system business accounts for the largest part of our production volume: Standard and special assemblies such as controllers or drive electronics are combined into control cabinets according to customer specifications, assembled, tested and delivered to the customer’s construction site in accordance with customer documents and plausibility checks. Additionally, WKC supports with design or measurement services. The customers and applications are extremely diverse and range from mechanical engineering and building technology to the food and beverage industry. Every year, the Siemens plant in Chemnitz produces more than 40,000 control cabinet panels, with an average batch size of about 1.5. “Almost every control cabinet we manufacture for our customers is unique,” says Puschmann. “Nevertheless, individual production steps can be automated.”

The basis for automated processing

Customers first discuss the technical details of a new control cabinet directly with the order center at WKC, and then the order-specific information (mechanical and electrical) is transformed into a digital twin of the end product, which forms the basis for all subsequent production and assembly steps at WKC: material logistics, mechanical processing of the enclosures, cable assembly, and electrical assembly, wiring, and testing. Even today, the manufacture of a control cabinet involves a lot of manual work, but production and assembly processes are constantly being optimized at WKC. For example, the laser receives the individual information for autonomous processing of the mounting plates from the data of the digital twin created in the work preparation department.

First steps towards autonomous assembly

Is autonomous placement of mounting rails and cable ducts on the assembly plate even possible?

The WKC team is currently working on automating the assembly of the mounting plates, as Thomas Puschmann explains: “After the holes and cutouts have been drilled, the mounting rails and cable ducts have to be assembled. We get information on the height, width and length of the cable ducts from the data records of the work preparation. The difficulty now is to feed the ducts to the autonomous machines for mounting on the slab – at the right time, in the right length and in the appropriate position.” About two years ago, at the Hannover Messe, WKC got into a conversation with Siemens colleagues from Research and Innovation, who were presenting an autonomous system for placing components on a mounting rail. Together with them, the task was to clarify: Is autonomous placement of mounting rails and cable ducts on the assembly plate even possible?

Thanks to a jointly developed test system, the first challenges have already been identified, according to Thomas Puschmann: “Whether or not I can use an autonomous machine in production depends heavily on the origin and quality of the data. There are still hurdles with individual assembly steps because the required component data is often still missing.” For each existing control cabinet component, it must be checked in advance whether a complete data set is available; missing information must currently be added manually. Because one thing is clear: If autonomous production is to succeed, complete data sets are a “must have”!

Skills as a basis for autonomous machines!

Autonomous machines must be assigned so-called skills that semantically describe their capabilities within the production environment and thanks to which they know their exact tasks. The processing of assembly plates thanks to autonomous machines already works very well in the Siemens plant in Chemnitz because the data required for this is contained in the digital twin.

A combination of digital twin and AI-based systems could be a key to compensating for the lack of data continuity.

But what happens with more complex production steps for which important information is missing? The validity and level of detail of the digital data are crucial. “The parameters that are anchored in the skills must be married to the data from the digital twin so that autonomous control cabinet construction can succeed – but there is still a long way to go until then,” Puschmann sums it up. “A combination of digital twin and AI-based systems could be a key to compensating for the lack of data continuity. Not only can data gaps be closed with a deliberate, intelligent matching of digital data with the real picture, it also considers tolerances within manufacturing that are missing with the digital twin alone.”

Christoph Lämmel and Thomas Puschmann with the autonomous machine (WKC)

Always focusing on the customer

Thomas Puschmann and his colleagues know: It will be at least another decade before a control cabinet can be manufactured in a fully automated manner, and fully autonomous production and assembly processes will not be available in this unique business in the foreseeable future. However, Siemens WKC in Chemnitz can already claim an important success on the road to automated control cabinet construction: Thanks to improved production and assembly processes, the plant is able to increasingly respond to customer requests and to put customers at the center of its production. Together with the precise production of larger quantities, a reduction in the workload of skilled workers and more flexibility that also enables customers to make changes at short notice, a major step has been taken toward customer-oriented production and competitiveness.