In close cooperation with logistics service provider DSV, STILL GmbH has set a new high in warehouse automation. The Hamburg-based leading supplier of intelligent controls for Intralogistics has comprehensively reviewed and optimised the flow of materials in the central European warehouse of General Electric Plastics. Continuous warehouse operation – which could not be interrupted – meant that the assignment, which involved replacing the floor of the building, was carried out under difficult conditions.

For the first time, STILL MX-X VNA trucks, which operate fully automatically without drivers, are deployed at the plant, in Bergen op Zoom on the Oosterschelde (between Rotterdam and Antwerp) in the Netherlands. The ingenious interaction between manually operated counterbalance forklift trucks, autonomous VNA trucks and STILL’s Materialflow Management System (MMS) not only improved the processes in the plastics warehouse considerably, but also reduced the costs sufficiently for the investment to be amortised in less than two years.

Transport and logistics group DSV was established only recently by the merger of DFDS Transport (Denmark) and the Frans Maas Group (Netherlands) and occupies a world-leading world position in this industry. The collaboration with STILL has been going on since the completion (in 1989) of the original warehouse, which was designed for completely manual operation. Three years later the first truck guidance system from STILL was installed, with data transmission through inductive wiring. In 1995 the narrow-aisle trucks were replaced by new STILL MX 16 models. The data from the first truck guidance system was intensively evaluated to provide valuable input during the planning and design of the new warehouse.

The newly-designed warehouse consists of 24 aisles, 107 metres long, with some 25,000 pallet locations. 18 aisles are automated with four STILL trucks, all able to operate in the immediately adjacent aisles to suit the material flow requirement, regardless of the zone disposition selected.

In the remaining six aisles the VNA trucks are operated manually. This allows unusual pallet sizes, often found in the plastics industry, to be located and retrieved efficiently. The autonomous MX-Xs are suitably upgraded standard trucks which can also be operated manually in the section of the warehouse allocated. “In this way we have enhanced the already high flexibility,” explained Jörg Brüning, STILL’s Warehouse and Materialflow Management Systems Manager.

Round-the-clock warehouse operation
After presenting the concept and budget quotation, STILL was asked to prepare the technical specification. This detailed document formed the basis for the order for implementation, placed at the end of 2003.

Analysis of historical data showed extreme peak loading on individual days and times. “Often, we have to cope with throughput doubling from one day to the next.” said Meinderdjan Botman, Solutions Director at DSV. It was therefore decided to run a simulation of the processes first, so as to avoid potential bottlenecks. This enabled storage and retrieval capacities to be matched accurately to needs, as were working times and breaks for the workforce.

The warehouse operates 24/7 all year including Christmas, with staff working 3 shifts. System capacity was designed to retrieve 67 pallets per hour and store 47 per hour – the difference being because despatches take place over five days but newly produced products are delivered all through the week.

“The particular challenge we faced in the warehouse redesign was the fact that operation had to continue without interruption. This is why the modification was done in five stages” explained Bart Peeters, General Manager at DSV. The work was greatly complicated by the need to remove the whole top layer of the warehouse floor, because it was not up to the high mechanical loadings of the past and was no longer joined to the sub-floor. In spite of this handicap not a single pallet was delayed or delivered wrongly during the period of the modification.

Over 3,000 pallets can be moved every day
The new system operates in three phases. The pallets are unloaded from lorries and placed in the transition area by Still counterbalance forklift trucks. A station, which first of all checks the contours of the pallets, hands over the pallets to the warehouse, placing them in two levels on carriages, with a vertical conveyor lifting the pallets up to the second level. At the ends of the VNA racking aisles the carriages pass on to the automatic MX-X trucks. Retrieval is processed in reverse order on the lower level which is always prioritized to offer the fastest possible response to GE Plastics’ customers, thus enabling the required maximum throughput of 2,565 pallets per day to be achieved.

The simulation had shown that the capacity is sufficient to retrieve 1,600 pallets and store 1,100 pallets, which leaves adequate room for manoeuvre for additional and future requirements.

The higher degree of automation of the warehouse in Bergen op Zoom is also down to the fact that in the Netherlands it is hard to find temporary workers and forklift truck drivers to cover the regularly occurring peaks at the end of each quarter. “By doing away with 17 jobs, we are much less dependent on the day to day situation on the labour market, or absence due to illness“ explained Meinderdjan Botman.

At the heart of the successfully-implemented project is the intelligence of the IT solution provided by STILL. The newly-designed MMSi even allows different configurations of the automatic operation, dividing the VNA warehouse into four, three, two or only one zone, depending on the demand.

“For us, on-time delivery to our customers is of the greatest importance,” said Meinderdjan Botman from DSV. “The STILL solution installed in our warehouse provides great security for us in this respect – as was impressively shown by the trouble-free conversion.”

Considerably improved capacity and flexibility at low cost
Without doubt the innovative modernisation of the warehouse has brought many benefits for the operator and owner of the location. The existing building can continue to be used, as can the existing racking system. The considerably lower investment ensures a quicker amortisation. A completely new solution would have cost around six times as much. The bottom line is that capacity and flexibility of the site have increased distinctly.

STILL also profits from the project: “The good collaboration with our partners has shown that our innovative approaches can be put into practice even under very difficult conditions – and that we can achieve a new level of warehouse automation”, said Jörg Brüning. “From this point of view Bergen op Zoom is a first class reference.”

However, this is not the end of the development by a long chalk: further improvements in warehouse automation are already being devised by STILL in Hamburg.