Automation of the last mile

At the thyssenkrupp Steering plants in Fameck (France) and Terre Haute (USA) automated guided vehicles ensure the flow of goods between the production line and high-bay storage area. Efficient control software and highly standardized processes ensure everything goes to plan. The effect: speed and safety have increased while damage, losses and thus costs have decreased.

Everything flows smoothly. In a seemingly endless cycle, employees at the thyssenkrupp Steering plants in Fameck and Terre Haute assemble steering systems from many individual parts. Boxes containing pre-assembled modules, ball bearings, tubes, etc. roll up to the production line, semi-finished parts leave the line again for the warehouse, and finished steering columns and gears head for the goods outward area – all on forklift trucks. Automated electric forklift trucks glide almost silently between machinery and storage bays as though directed by an unseen hand. Everything flows smoothly and components and materials are supplied to employees at their workplaces at precisely the right moment.

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This system is called ONE Flow AGV and automates goods flows in the so-called last mile between the material warehouse and the assembly area on the production line. Two types of automated forklifts – AGVs (Automated Guided Vehicles) – are generally used: FLVs (Fork Lift Vehicles) and VNAs (Very Narrow Aisle Fork Lift Trucks). At the Fameck plant both AGVs are used. But the system cannot manage entirely without manually operated forklifts. These vehicles bring the delivered goods to the conveyor who checks the dimensions and integrity of the handling units before passing them on to an FLV. The FLV then delivers the goods to the handover point in the high-bay storage area where the VNA places the handling units in the 8.30 m high storage bays. When the components are required for production, the VNA collects them again and passes them on to an automated forklift (FLV).

As the Terre Haute plant does not have a high-bay storage area, no VNAs are used there. The handling units delivered here are placed in transfer bays using manually operated forklifts and the FLVs remove them from the other side, e.g. to put them into storage.

Constant comings and goings

Finally the FLVs bring the components and empty containers to the production lines. In the other direction they also transport empty containers as well as semi-finished and finished parts which are then put into high-bay storage (at the Fameck plant) by VNAs or the warehouse (in Terre Haute) by FLVs, or further FLVs take them to the shipping area – the second half of the cycle. The forklifts can transport containers or handling units weighing up to one ton and travel at around six kilometers per hour. The production lines at both plants have up to 100 different setdown points while the high-bay warehouse (in Fameck) has room for approx. 7,000 items.

FLVs and VNAs navigate through the production shop using laser scanners. The provider’s transport software calculates the route and guides the vehicles precisely to their destination where they either deliver or collect goods. A warehouse management software system tells them where to go, which goods and finished parts need to be transported and set down where – and how to get there as quickly as possible. Each individual assignment is triggered by the machine operator. The two programs communicate with each other to find the quickest available vehicle and the contacts on the production line transfer the information about the goods and destination to the FLV.

Complex automation system

The autonomous forklift trucks form the heart of ONE Flow. To ensure they can move around effectively and above all safely, the working environment and processes in both plants have been adapted to requirements of the AGVs. “We have completely changed workflows and standardized interfaces where for example goods arrive at the production lines,” says Olivier Martinelle, Supply Chain Manager at the Steering plant in Florange-Fameck. The setdown points at the machines now all have roughly the same dimensions. “Automating shopfloor logistics means much more than just using automated vehicles,” continues Martinelle. The implementation of the ONE Flow program in the plants involved constant, close collaboration with the plant functions (Olivier Martinelle and his supply chain team for France; Andy Völkl and his continuous improvement team for the USA) and the Corporate functions (Fabian Liebetrau and his team from CC Lean Services). In total more than 30 employees were involved and the implementation necessitated a major coordination effort in a cross-functional team (logistics, production, quality, etc.). The meticulous change management approach to preparing the plants and their employees for the implementation is also worthy of note. In total more than 700 employees received training.

The development of ONE Flow took just over two years, with the preparation of the technical specifications, process organization and definition, and system implementation by the supplier each accounting for one third of the time. In an extensive simulation the planners calculated the number of vehicles required: 25 FLVs and 6 VNAs in France, and 10 FLVs in the USA. “The ratio is perfect,” says Fabian Liebetrau. The flow of goods has run smoothly and completely accident-free since the launch in September 2016. In addition to Fameck, BU Steering has now also implemented the system in the Terre Haute plant in the USA.

Martinelle and Liebetrau are very satisfied with their experiences with ONE Flow there and at the plant on the Franco-German border. “We were able to optimize space utilization meaning that we can now store 50% more goods and material,” says Martinelle. Costs and damage to the storage bays have also been reduced. “The FLVs and VNAs are equipped with such sensitive sensors that they quickly identify any risk of a collision and stop,” says Liebetrau. The flow of goods at the Fameck plant has become more transparent and safer thanks to ONE Flow.

You now see fewer forklift truck operators inside the plant than in the past but they are still needed to load and unload trucks – the AGVs cannot manage that (yet). Many forklift operators have taken on other roles, for example as supervisors who monitor the automated process. “Together with employees we have acquired new skills,” says Martinelle. So that everything flows smoothly.

The automation of the last mile through the ONE Flow AGV project at the Steering sites in France and the USA can be seen as a success. Alongside the digitization and automation, safety and quality of work have improved at the plants. The savings realized through the implementation also improve efficiency in particular in high-wage countries.