Kanban systems are indispensable in manufacturing plants and offer many advantages. Nevertheless, error-prone manual workflows and low digitalization mean that there is room for improvement. Bosch Connected Industry (BCI), Pepperl+Fuchs, and Neoception have partnered together to develop a complete solution that adapts Kanban racks for Industry 4.0 and is equally suited for greenfield projects and retrofits.
Since being developed by Toyota for use in production, Kanban systems have been hugely successful worldwide. The system is based on the shelf replenishment process in supermarkets, demonstrating the sophistication of Japanese engineering. Commonly used in production and logistics processes, the technology has long since spread to software development and project management. Yet the tried-and-tested original—the production-based Kanban system—still has great potential for optimization. Although the strengths of the production-based system are well-known, numerous aspects are less advantageous, as Omar Rahman, Product Owner Stock Management at Bosch Connected Industry (BCI), notes: "Naturally, with changes in stock levels recorded manually, the process is susceptible to errors. These errors cause discrepancies between the system inventory and the physical inventory." Tobias Kehl, a Digitalization Engineer at the Pepperl+Fuchs subsidiary Neoception, is also very familiar with the limitations of Kanban systems: "Since the use of digital technology is generally minimal, there is still great potential to improve the transparency and consistency of information in Kanban circuits."
Since the use of digital technology is generally minimal, there is still great potential to improve the transparency and consistency of information in Kanban circuits.
All Fired Up
Since Bosch offers its customers components for Kanban processes and uses these components in its own production and logistics, the company had a vested interest in developing the system to make it suitable for Industry 4.0. The resulting solution had to be easy for large global companies to integrate into greenfield projects and suitable for retrofitting existing systems in small and medium-sized enterprises. "To implement such sophisticated IoT applications, we established Bosch Connected Industry in 2018. We have 500 employees working exclusively on Industry 4.0, digitalization, and network applications, including manufacturing, logistics, and software specialists," says Matthias Hülsmann, Vice President of BCI, explaining the structure of the Bosch business unit. He then explains that external expertise was still needed to take Kanban systems to the next level: "A truly groundbreaking solution required the appropriate industrial sensors, so we explored relevant companies that Bosch was familiar with: Who could bring the necessary level of expertise and would be interested in getting involved in the project?"
After exploratory talks with Pepperl+Fuchs, a partnership was formed. The deciding factor was that the Mannheim-based automation specialist not only had decades of experience in sensor technology, but also had a subsidiary—Neoception—that specialized in developing software for Industry 4.0 solutions. “Pepperl+Fuchs was very interested in the project, and the team at Neoception was as equally fired up to work on enhancing Kanban systems with a globally renowned partner such as Bosch," says Bernd Fischer, Key Account Manager Bosch Group at Pepperl+Fuchs.
Pepperl+Fuchs was very interested in the project, and the team at Neoception was as equally fired up to work on enhancing Kanban systems with a globally renowned partner such as Bosch.
Digital Images of Real Racks
The newly formed, interdisciplinary team immediately started working to pursue the shared goal of an end-to-end connection between operational technology (OT) and information technology (IT). "In simple terms, we aimed to digitally map and control a conventional Kanban rack—with all of its typical elements such as individual tracks and small load carriers—including all processes relating to management, supply, and error-free use of the racks," explains Hülsmann. Based on this goal, the team developed sensors and software adapted specifically to the application.
Pepperl+Fuchs' extensive portfolio of technologies, including RFID, proved to be a major advantage. Noncontact identification technology makes it possible to easily and reliably determine which materials have arrived in the production supply area. The higher-level Bosch system can be used to determine which tracks should buffer these materials. In addition to stationary read heads, RFID wristbands can be used for easy detection of RFID tags in motion.
Light Strip Ensures Better Transparency
For the second key stage, the team focused on monitoring and controlling the individual rack segments. In this stage, each compartment was equipped with a photoelectric light strip, a dedicated rack controller, and an LED module for displaying the put-to-light work instructions. The core element of this part of the solution is undoubtedly the specially developed light strip, which features intelligent software evaluation, as Sebastian Pesch, Product Manager Customized Applications at Pepperl+Fuchs, explains: "Using individual visual background suppressors on the sensor bar to detect small load carriers in the rack allows us to identify patterns in the software almost in real time and draw conclusions about the movements in the tracks. The LED module uses colored signals based on this information to indicate if the box has been placed on the correct track. In addition, the bar is available in different lengths, which means it can be easily adjusted to the dimensions of the respective rack."
Designed for Unprecedented Results
The rack controller, also developed specifically for this application, acts as a link between sensors, LEDs, and the higher-level controller. When deciding to connect the light strip, LED module, and rack controller, the team continued to prioritize high system flexibility, which is why they used an AS‑Interface flat cable with piercing technology.
This clever solution means that users can react dynamically to different distances between the tracks and connect up to 50 racks to a single higher-level controller. As Pesch reports, this results in other important advantages: "Ensuring all components are easy to install contributes to our overall goal: The new solution can be used for both new plants and for retrofits. Just a few retrofits can turn a manual Kanban workflow into a digital map to improve transparency and efficiency." Bosch Connected Industry also considers this concept to be groundbreaking: "Existing solutions on the market either use just RFID, wireless technology, or traditional mechanical switches. However, there are serious drawbacks to all of these approaches. Our solution offers significantly more reliability and cost efficiency. It also provides an unprecedented end-to-end digital information flow," comments Stephan Schumacher, Cluster Owner Intralogistics in BCI Product Management.
Sophisticated Software for More Efficiency
Looking at the system in operation, it is clear that it exceeds the already high expectations: Wearing RFID wristbands, Bosch production personnel act quickly and efficiently when depositing small load carriers on the rack. The put-to-light signals provide clear instructions for the next work step and indicate any errors in the depositing of items. A dashboard on a connected HMI automatically visualizes workflow information and allows information to be recorded manually. The green light on the status stack light of the rack indicates that all components are working correctly. Facilitating such smooth interaction required groundbreaking software components and intensive deliberation during the development of the hardware components.
The stock management application from the Nexeed Industrial Application System developed by BCI is used for planning, control, and intralogistics processes. This application acts as an interface between the ERP and the main controller of the rack, which is equipped with software programmed by the Pepperl+Fuchs subsidiary Neoception. Once the stock management application lights have shown the operator which rack is to be loaded, sensors detect the small load carrier being inserted into the rack. Operated by Neoception's controller software, the industrial PC (IPC) generates information about whether, how often, and where the operator accesses the rack. If the operator accesses the wrong rack, the error is immediately detected and signaled. The real-time material posting is only completed once the error has been rectified and the container has been positioned in the assigned rack.
Additionally, the software can use container size information from the stock management application to verify whether the number of physical boxes matches the virtual material stock. This means that the stock on the rack is constantly monitored, visualized via electronic rack indicators and the stock management application, and updated in real time based on the supply and usage rate of the parts. When the stock level in a rack falls to a predetermined limit value, the system automatically submits a request to replenish the stock and initiates the process of transporting the relevant parts. The IPC aggregates the sensor data, interprets the detected patterns, and converts the findings into validated process events.
"Furthermore, the service we developed for the main controller provides device and permission management for local components and monitors the status of sensors and gateways in the field. However, process events can also be buffered to avoid overloading the ERP or warehouse management system. It is also possible to establish a simple and secure connection to various cloud services," Kehl says, explaining the full range of functions.
Joint Market Entry
After conducting extensive tests within Bosch's internal production, Bosch Connected Industry, Pepperl+Fuchs, and Neoception are entering the market together as equal sales partners. BCI has integrated the application into the Nexeed Industrial Application System in the form of stock management. Pepperl+Fuchs and Neoception are offering the solution as a "digital Kanban management system," with Neoception enabling this system to be integrated into other software systems.
By the end of last year, the success of this partnership was already clear. Pepperl+Fuchs and Neoception won the Bosch Supplier Award and took second place for the Bosch Innovation Award, which Fischer was delighted to receive: "Once again, Pepperl+Fuchs and Neoception have proven themselves to be competent business partners for sophisticated Industry 4.0 projects that require an intelligent combination of sensor and interface expertise." Commenting on how BCI considers the project a success, Hülsmann says: "Together with the new, completely digitalized Kanban rack, we are able to increase flexibility and process stability in our customers' production, optimize processes, and reduce inventory costs—what's more, systems can be retrofitted with the solution. The complete hardware and software solution that BCI, Pepperl+Fuchs, and Neoception now offer will be a welcome breath of fresh air for the field of Kanban management."
The complete hardware and software solution that BCI, Pepperl+Fuchs, and Neoception now offer will be a welcome breath of fresh air for the field of Kanban management.