THE SOLUTION

The automated vertical warehouse designed for Spendrups features 45,000 pallet slots and is capable of simultaneously handling 300 pallets per hour coming from the factory production linked via the bridge, 50 pallets per hour from the external production warehouses and 400 pallets per hour to the shipment stations, which include 55% of mixed pallets prepared for picking. The SKUs (loading units) handled by the system are 800x1200 wood and plastic Europallets and 800x600 half-size pallets. The storage section consists of a singledepth self-supporting shelving, where twelve 36 metre high, bi-pallet, two-column stacker cranes slide along a 130 metre long aisle. Each stacker crane carries two pallets at a time.
Next to the HBW, in a 7.800 sqm area, man-to-goods picking is performed. Class A references (very fast moving), are handled on gravity roller conveyors in fixed picking bays (each dedicated to a single reference code), and are fed by rectilinear shuttles with ARP system (Automatically Replenished Picking) from the HBW. Slow or very slow moving references (Class B and C) are deposited to a manual shelving warehouse, which follows the traditional concept of stock lowering. In this second case, refilling is manually managed by the operator starting from the pallet sent by the HBW to replenish stocks. Each picking operator executes the order given by the management system using radio-frequency controlled terminals, following optimized routes through the manual picking area.

The completed mixed pallets are brought back by the operators via mechanically-operated bays., they are read by the system, then wrapped and labelled and finally
delivered to the HBW. This is actually the meeting point for all the pallets belonging to the same shipment (full and mixed pallets).
The shipping system follows the just in time criterion: all the products are kept in the warehouse and are retrieved only when the truck is in position at the loading platform.
The bay is used as a dynamic buffer which progressively retrieves the pallets from the HBW, so as not to occupy the shipment areas when not necessary, in the event that,
for example, the truck is late. This way, the total surface of the loading platform is as small as necessary and truck loading efficiency is maximized.

CHALLENGES

Several challenges have been faced to develop a solution: coordinate and manage storage, order preparation and shipment of a high flow of goods featuring several different brands; satisfy the various specific requirements previously agreed with the different types of customers relating to order and shipment processing; ensure reduced processing and reaction timeframes of the logistic system; obtain economic benefits compared to the existing organization, at the same time balancing the investment costs with the operating costs; ensure working conditions comparable to the best Northern European standards; design and implement an effective link with the new area hosting the logistic site of Grängesberg, as a high traffic public road and a railway separate it from the production site in the existing factory; organize the start-up of the new site without affecting the normal logistic activity.