Having booked total orders at Bauma worth more than DM100m ($43m) there is little wonder that Liebherr is expanding its German mobile crane factory. Doubling the output at Liebherr-Werk Ehingen in the last four years has been achieved with major plant expansion and higher productivity. Increased competitiveness is the target, to be achieved by reducing costs per unit and optimising throughput times of the all-terrain, truck and crawler cranes manufactured at the Ehingen factory in southern Germany. To do this Liebherr has constructed a new production building of 44,000m2 (News May 2000, p5). This gives the plant an annual production capacity of 1,400 mobile cranes, Liebherr claims.
The factory’s first full business year was 1970 when the 162,000m2 site had 372 employees and a turnover of DM8.7m. ^By 1998, prior to the latest expansion, the site was up to 331,000m2, employees numbered 1,683 and turnover had reached DM1.3bn ($565m).
Much of the demand for expansion came from the world-wide growth in sales of all-terrain cranes. By 1997, despite optimisation within the available buildings, production capacity limits were being reached increasingly often. Expansion was only possible to the north of the site, and that was a valley that needed a lot of fill – to a depth of 28m in some places.
Land purchased for the expansion has brought the site area up to 535,000m2 (roughly 30 full-size soccer pitches). Earthmoving work included the removal of 570,000m3 of material, and 480,000m3 filled using material brought in from outside, with another 50,000m3 still to do.
Assemble in the hall
Planning the four-aisle building involved consideration for the retention of proven manufacturing principles but also combined these with the latest thinking in factory planning. Flexibility was key, in terms of being able to adapt to changes in market requirements, for example, to accommodate a big contract or sudden surge in demand, and the ability to build 200 more units as required.
Total area of the new production building is 44,000m2 and the assembly area is 372m long, 100m wide and 25m high. Main components are brought together here and assembled, including the chassis, slewing platform and then the pre-assembled booms. There are two production lines, running in parallel, one for chassis and the other for slewing platforms. Synchronisation of the two lines means that the correct slewing platform meets the right chassis on time.
Next to the main assembly lines are the internal suppliers of pre-assemblies such as cabins, winches and outriggers. The supply of the more than 5,000 individual parts is administered using computers, and special crane specifications can be programmed in. Employees have designed their work areas according to their own ergonomics to produce the best work sequence.
The logistics of the material supply to the production lines are designed so that components can go straight to the production line instead of into a separate intermediate buffer store. This also applies to major components coming straight in from outside suppliers such as engines and transmissions. Internal and external suppliers are integrated into the same computerised material flow system and must meet the same quality and punctuality standards.
The depth of in-house manufacturing is between 15% and 20%, depending on crane type, and about another 15% of components are produced within the Liebherr Group. These include engines, hydraulics and electronics. About 80,000t of material passes through production every year and each working day between 80 and 100 trucks deliver the components that come from outside the Ehingen plant.
New mechanical handling and assembly equipment includes 24 indoor cranes, 65 gantry cranes, 24 wall mounted slewing cranes and many small handling devices. Robots are used to automate axle installation and there is a chassis rotating device. Overhead energy supplies are fitted in all work areas and air-cushion transport systems are to be install to make it easier to move heavy components.
The future
Now assembly has been moved to the new building, space has become available around the plant to expand other areas. Boom construction is being moved to the former final assembly shop where it will be easier to assemble and test the longer booms because there is more space. This in turn frees up more space, to be occupied by the sheet metal and mechanical production departments.
Steelwork is going up for a new repair shop, due for occupation in December. This will handle repair, maintenance, and reconditioning work solely on Liebherr mobile cranes. Construction is also soon to start on a new despatch building where cranes will be handed over to customers and where other equipment they have purchased will be loaded.
Two extensions are planned for next year. One is an enlargement of the pre-delivery and final finishing area and the other is an extension of the administration block to give more space to the design and development department.
Product development
Developments at Ehingen are not confined to the production facilities. Liebherr’s entire range has been renewed in the last 10 years, according to design and development director Ulrich Hamme. ‘Between 1990 and 2000 Liebherr either developed or extensively revised 29 crane models. Today our sales programme consists of 13 all-terrain cranes and five crawler-track cranes, but these only represent about half of the development work we undertook in the past 10 years,’ Hamme says.
More than 150 engineers and designers do the development and revision work on the cranes. Last year 70% of new crane turnover came from models that were less than three years old, according to Hamme. Forthcoming design improvements focus on ergonomics. A new crane cabin will have more leg room and an improved control element layout. It will also include GPS navigation and new radio and communication equipment. A hybrid combination of mechanical and electronic steering will appear soon, Hamme says, that will involve control software.
Engines to comply with Euro 3 emissions regulations have an improved injection system. The three valve per cylinder design will be replaced by four valve heads by 2004.
Recent leaps in boom developments include the use of 1100 grade steel and rounded profiles, but Hamme says further optimisation is possible by closing up the section profiles. As for boom materials, he says there is still no subsitute for steel.
