Liebherr’s new pallet handling system with turning and milling centres

High performance and the use of state-of-the-art technologies in production play an important role at Liebherr. With this in mind, Liebherr Components has introduced a new pallet handling system (PHS) at its production site in Biberach (Germany). The PHS is linked to two turning and milling centres for the production of powerful drive units and rope winches.

“We have replaced our previous machining centres on site to be able to cover the high product variance with greater flexibility”, explains Florian Kraljic, manager of the cubic parts department at Liebherr in Biberach. The new machining centres, however, need to do more than just milling, they should also be able to turn work pieces and connect to the PHS. The concept behind the idea is to manufacture raw and finished parts in just one sequence – flexibly and around the clock.

The new PHS allows a large number of work pieces to be fully machined in a single work sequence. With an appropriate tool management, two machines can produce in parallel. Different components can, thus, be manufactured simultaneously. All this allows a high variance of components – 67 machine pallets or chucks and 62 material pallets can be stored in the system. If necessary, the system is further extendable. But the size of the system is already impressive. Together with the PHS, the machines take up the space of half a football field. The turning and milling centres are equipped with very large tool magazines with each machine holding around 700 tools.

If the work pieces are particularly heavy, the chucks should ideally be lighter to exploit the maximum loading weight of the handling system and machining centres. This balancing act has been a success due to the chucks supplied by Röhm GmbH. “We can machine connecting parts, end plates and cable drums made of steel or cast iron with a diameter of up to 1,200 millimetres and a weight of up to 1,200 kilograms in the machines”, says Florian Kraljic.

In addition to the production of parts for Liebherr own components, the company also acts as a contract manufacturer in the market. Therefore, Liebherr attaches great importance to flexible production and completing manufacturing orders with batch sizes from one to larger sizes. The implemented vertical integration has made a special working time model possible: after eight hours, the system continues to produce components for four hours without an operator, followed then by another eight-hour shift and a subsequent four-hour production without an operator. This enables Liebherr to reduce the burden of night shifts on the employees. After a raw part has been clamped, no further individual machining processes with time-consuming re-clamping during the machine cycle are required. All this reduces the physical strain of the machine operator, allows work that is easier on the joints and creates ergonomic setting stations. The worker can now complete all his work at the setting stations at ground level, at a workplace freely accessible from all sides.