Case Study: Smart Factory

The increasing flexibility of production processes, associated customization requirements, and the push for “batch size 1” production are key drivers of the concepts of Smart Factory and Industry 4.0. A leading research organization in this space is SmartFactory^KL, a special interest group specialized in the practical validation of theoretical manufacturing concepts. In collaboration with industry partners, SmartFactory^KL develops and tests industrial systems in realistic industrial production environments. This case study relates to the Industry 4.0 demonstration system that was showcased at the Hannover Messe industrial technology fair in 2014 [DF1].

The Industry 4.0 demonstration platform is a production line that allows the automatic assembly of customized business card holders from various components, the engraving of business names via laser, and the automatic completion of basic test functions. Bosch Rexroth and Harting modules are used for assembly, a Festo module is used for the engraving, and a PhoenixContact module is used for laser writing. Quality assurance is provided by a module developed by Lapp Kabel. MiniTec has provided a manual workstation with integrated augmented-reality guidance features. The image below shows the assembly line, as demonstrated in Hannover in 2014.

What makes the assembly line so special is that it can be reassembled dynamically thanks to its modular structure. As demonstrated in Hannover, the sequence of the production modules can be changed in a matter of minutes. All production modules are fully autonomous; there is no central MES or other production control system involved. This is achieved using digital product memory, which stores product configurations as well as the corresponding work instructions and work history. The Festo module is responsible for starting the production process. This is where the base casing of the business card holder is unloaded and customer-specific data is engraved onto an RFID tag, which is then attached to the base plate. The module then engraves the base of the holder itself as per customer specifications. Next, the Rexroth module mounts the clip to the base casing of the business card holder. Depending on the customer’s specifications, the Harting module then places either a blue or black cover onto the base plate and force fits the two components together. The PhoenixContact module then takes over, using a laser system to add an individual QR code and lettering to the product. The last module in the assembly line is the LappKabel module, which performs a quality check and releases the final product. Other partners such as Cisco, Hirschmann, ProAlpha, and Siemens have also contributed their expertise to the project. This has allowed the integration of different IT systems and the creation of a backbone structure to feed the individual modules of the assembly line. The key elements of the assembly line are shown in the figure below.

A key objective of the Industry 4.0 demonstration platform was to show how standardized production modules can be easily integrated and exchanged. Project initiator and Chairman of the SmartFactory^KL Board, Prof. Dr. Dr. h.c. Detlef Zühlke explains: “To ensure the modularity of production systems, the mechanical, electrical, and communication interfaces need to follow standards. Useful standards can only emerge on the basis of actual requirements and experience. This means that standards have to develop simultaneously with the adoption of Industry 4.0. Already there are a number of standards available at different levels, and we should use these standards. We do not need to start from scratch. It’s only at higher interoperability levels that a lot more work still needs to be done.”

For the Industry 4.0 demonstration platform, standardization was achieved at a number of levels:

• Digital product memory: Digital product memory is integrated into the various workpieces using RFID technology. Data is exchanged between the workpieces and the production modules based on a standardized cross-manufacturer OMM data format (Object Memory Modeling), [WW1]
• Vertical integration: Production modules and business applications are integrated based on the OPC UA standard
• Transportation of workpieces: An innovative sluice system was devised to facilitate the interconnection of production modules and the standardized conveyor belts within them.
• Assembly line topology: Automatic neighborhood detection for independent topology derivation
• Production modules: All modules support EUR-pallet dimensions

Asset Integration Architecture

The figure below provides more details of the solution’s individual components. Each product has an RFID tag that can be read and written to from a remote device (a). The tag stores product configuration data and the work history. Each production module has an integrated RFID unit that accesses this data from the product in order to read work instructions and create new entries in the work history (b). The ERP system creates the work definition for the product using the Festo module’s RFID unit.

The use of product memory and a standardized data exchange format to control the production process across multiple production modules is very interesting, because it simplifies integration. Instead of having to integrate all modules into one complex central system, the interfaces are loosely coupled and relatively simple. The product controls its own flow and the work that has to be done in this flow. Especially in cases where products are worked on in multiple organizations, this has the potential to greatly simplify integration and provide for much greater flexibility.

The modules in the demonstration platform have different architectures. Some follow a more traditional approach; for example, module A has a PLC for controlling the pick-and-place units, and uses an OPC UA server to provide access to the business logic in the backend.

Module B reads the customer name and address from the product’s RFID tag and then uses this data to create a customer vCard, which is lasered onto the business card holder in the form of a QR code. Again, the laser is controlled from a standard PLC. It is also planned to use SOA-2-PLC for backend integration.

In the future, Module C will also be a little bit different from the other modules in that it will use a small but powerful Linux-based microcontroller to create a single, integrated network of actuators/sensors (pneumatic press, for example) with their own intelligence.

The physical coupling of the modules is based on a standardized hatch through which the products are moved (c). This hatch allows conveyer belts within the modules to move the product from module to module.

The central functionality provided by the backbone is the supply of power, pressured air, Industrial Ethernet, and an emergency stop function. There is no central SCADA or similar system involved. This means that production modules can be used as individual plug-and-play units, and their sequence changed in a matter of minutes.

Conclusions and Outlook

Thanks to the integration of product memory, the SmartFactory^KL demonstration platform has shown that important Industry 4.0 concepts such as Single-Item Flow and Loose Coupling of Production Modules can be implemented using technology that is already available today. The SmartFactory^KL consortium plans to build on the concepts demonstrated in the system, and to add additional modules from new partners. The production process used for the demonstration will be extended and its capabilities enhanced on an ongoing basis. The first update is set to be unveiled at Hannover in April 2015.

The industry partners involved in the project are keen to transfer these concepts from a research environment to live production environments. However, this is unlikely to happen any time soon. According to Prof. Zühlke, there is more work to be done: “In some areas, like in semiconductor production, we have made considerable advances in establishing module standards. However, I think it will be at least another three years before we start seeing initial implementations of the Smart Factory in a live production environment. In terms of full implementation, I think we are talking 10 years or even more.” However, Prof. Zühlke is keen to stress that companies should not miss the boat: “Some companies are already under pressure to keep up with ongoing developments. Industry 4.0 is not just a minor trend; these concepts and technologies represent a fundamental paradigm shift that will completely transform the manufacturing landscape as we know it today.”