Standard, yet individual
With the PHS 10000 Pro pallet handling system from Liebherr-Verzahntechnik GmbH, the machine tool manufacturer GROB in Mindelheim has automated its in-house production of machine components on two 4-axis machining centers and thus increased productivity by around 45%. The challenge here was not only to manage large parts weighing tons, but also a series of additional constraints that required highly individual solutions, as well as project planning where not a single day‘s work could be delayed.
GROB-WERKE GmbH & Co. KG is a globally active, family-owned company that develops and manufactures production and automation systems with a prominent level of vertical integration and a substantial proportion of in-house production. GROB delivers its products to automobile manufacturers and their suppliers as well as to companies from various industrial sectors worldwide. Founded in Munich in 1926, the company today manufactures the entire product range at its headquarters in Mindelheim with 5,800 employees on almost 200,000 square meters of production space. The company has additional production sites as well as service and sales offices all over the world.
“For me, Liebherr is a competent and innovative partner that proactively assisted us in successfully implementing the project on time.”
Securing the location by increasing productivity
GROB already has a high degree of automation and is continuously expanding it. The aim is to achieve round-the-clock production with minimal personnel. “This is part of our strategy for securing operations in Germany. We want to use automation to react to demographic trends, while also remaining competitive despite increasing wages and ancillary costs,” explains Jürgen Kreibich, Head of the Large Parts Production department at GROB.
In this case, the plan was to modernize and refit two 4-axis machining centers and link them to a linear storage system and an automatic loading system. The machines are used to shape large castings for the company‘s own products, such as spindle housings, table brackets and machining carriages. Each part weighs up to six tons, and with the pallet and clamping fixture up to eight tons. Manual machine loading using a pallet changer with a zero-point clamping system and hydraulic crane meant long setup times; and setup during the machining process was highly laborious. The automation project received funding from the German Federal Ministry for Economic Affairs and Climate Action (BMWK); however, this produced the first challenge, because the funding was connected to a very tight timeframe.
Compact layout and good advice from Liebherr
PHS 10000 Pro – individually configured
In this case, the PHS 10000 Pro linear pallet handling system consists of a heavy-duty storage system which offers pallet storage space for 16 workpieces and a trolley that can carry up to eight tons. The consignment of workpieces to the machining centers is controlled by a host computer from Procam. The setup station is mobile, because a ceiling beam prevented the use of an indoor crane, and equipped with monitors with which the operators can keep an eye on the machining chambers and the processes. A state-of-the-art suction system has also been installed. A special solution was developed for machine loading – but more on this later.
So many special solutions, so little time
The project presented both sides with numerous challenges. The two existing GROB BZ1600 machines, large machining centers built in 2009 and 2012, were overhauled and brought up to date with the latest technology. Due to the expected higher productivity of the system, the tool magazines of the machining centers were also expanded from 270 to 450 places. All around them, the pit in the hall floor, where the pallet changers for the machines used to be, had to be enlarged and reconcreted for the PHS trolley. To make things even more difficult, the two machines were not exactly aligned to each other.
The conversion of the lift module in the trolley was also a special solution. Because the PHS had to be closer to the machines for reasons of space, a pallet changer could not be used. “Our development department designed the crucial solution here,” explains Knut Jendrok, Sales Manager for Pallet Handling Systems at Liebherr-Verzahntechnik GmbH. The lift module, which is only designed for depositing pallets, was adapted so that it also pushes the pallets exactly into the T-slot of a loading rail.
The confined space required an unconventional approach during assembly. Bringing in the PHS trolley was particularly nerve-wracking for the project managers: weighing 22 tons, it was lifted into the pit behind the half-installed shelf- magazine. “We had to extend the truck crane far under the roof. There were only two centimeters left between the skylight and the crane boom,” remembers Christian Geiger, Large Parts Production Foreman at GROB. All these challenges had to be overcome in a narrow window of only a few months, because the BMWK funding guidelines set a fixed deadline for when the system had to be operational. “It doesn‘t happen often – but in this case the project schedule was perfect for the day,” praises Jürgen Kreibich.
Pallet storage spaces for workpieces weighing up to 16 tons
Higher spindle utilization with reduced personnel deployment
The automated system increased spindle operation time by 66% with reduced personnel deployment – which is more or less the maximum degree of automation that can be achieved in large parts production with its complex machining requirements. The aim is to ensure long-term utilization of the system in three-shift operation, six days a week. “The added value comes from the ratio of spindle operation time to working hours: the automation allows spindle utilization of up to 90%,” explains Knut Jendrok. Christian Geiger adds: “We‘re currently trying to find optimal shift models to achieve as many unmanned hours as possible and optimize personnel deployment. Automation also relieves the burden on employees, who now don‘t have to work as many night and weekend shifts.”
GROB WERKE GmbH & Co. KG
Sector:
Mechanical engineering
Company headquarters:
Mindelheim (D)
Employees:
approx. 8,000 employees
Founded:
1926
An experienced team and smooth cooperation
The people at GROB are incredibly happy with how the project has gone. In particular, they regard Liebherr‘s proactive approach, solution orientation and short reaction times as essential for the successful implementation of all the individual requirements. Liebherr also appreciated the close cooperation: “We were able to tackle the sometimes-challenging issues so well because coordination throughout the entire project team was always very constructive and smooth,“ says Christopher Nigg, Project Manager at Liebherr-Verzahntechnik GmbH. Florian Ziegler confirms: “For me, Liebherr is a competent and innovative partner that proactively assisted us in successfully implementing the project on time.“
