Because Kordel produces around 25,000 different parts in-house, the material supply must be adapted to this huge variety. The processes are determined by the batch sizes of typically five to 30 parts per order. This makes the supply of materials a critical aspect; the shuttle that brings the blanks to the machine must not become a bottleneck. “The machining center is the most expensive component; it must always be running and must never have to wait for the connected systems,” says Johannes Kordel, summarizing the most important specification. It quickly became clear that, at the required cycle time, this could not be done with a single system. This was the determining factor for the system to consist of two lines: a material storage system and a production system, each with a storage and retrieval unit. The two systems continually communicate with each other via a shared control system. When the idea for the architecture with two lines was first conceived, it was calculated how many machines could be operated with this type of system. As a result, the pallet handling systems are now designed for up to six machines. There are currently five identical machining centers at both locations.

The lines are laid out in parallel to minimize the distance between the two sides. To maintain a high frequency and short cycle times, smooth processes at all the transfer points are required. On the material side, there are two loading and unloading stations for forklifts and eight for manual removal. When storage and retrieval unit 1 takes a finished housing from the machine to a setup station of the production system, storage and retrieval unit 2 removes a lattice box for finished parts and a lattice box with raw parts from the material storage system. All the required tools have to be stored and kept in stock as well. A small number of very specialized measuring devices are not provided at every processing station, but most of the workpieces will be processed at all the stations. In addition to the six setup stations on the machine side, which are arranged in pairs and operated by a total of three employees, there is a separate station for more complicated items, new clamping fixtures or problem cases so that the employees can continue working undisturbed at the double stations. The machine processes the job and returns the clamping fixture. Each component has its own lifting appliance, which must be provided at the right time. These accessories for specific workpieces are also essential for successful automation.

Alongside the technical expertise that Liebherr demonstrated with a gear cutting machine in Kordel’s gearbox manufacturing facility, Liebherr’s communication and flexibility were also deciding factors for the renewed cooperation on the automation project. “The first meeting with all the representatives took place within just 14 days. At that meeting, they were able to answer all our questions. This made us feel confident about the project from the beginning,” says Johannes Kordel, recalling the start of planning. What he liked most of all was that Liebherr listened. “We formulated our ideas and a system was developed that is precisely tailored to our situation. That’s not possible with companies who only let you order from their catalogs.” Once the decision had been made in favor of the PHS 1500 PRO, all the details were discussed and individually resolved on a regular, often daily basis. The various adaptations and the two-line architecture, which was new to Liebherr too, made the project an exciting experience for both sides.

Liebherr’s strength lies in its ability to flexibly implement individual customer requests. For example, Liebherr takes care of the connection to existing production systems and adapts the interfaces. At Kordel, all elements of the new production line communicate via the existing host computer supplied by the Berlin company PROCAM Steuerungstechnik.

Knut Jendrok, Liebherr’s Head of Sales for Pallet Handling Systems says: “The specific issues that Kordel brought into the planning weren’t at all obvious ones. It’s extremely helpful when a customer formulates its requirements so precisely according to the circumstances. This helps us work well together and it becomes a productive cooperation.”