Previously, slower-moving lines were picked from static shelving, with the very slow-moving lines being located further away than other slightly faster lines, which meant staff had to walk further to collect slower lines, making them more expensive to pick. Also, with the storage height of these lines limited by the scope of human reach, use of storage space was inefficient.
With the new OSR, staff no longer need to walk at all to pick the orders, dramatically reducing the cost per item picked for AAH. The company commissioned Knapp, which had supplied the automated handling solution at the Nexus Point facility, to replace a large section of the static shelving with its new OSR system. The OSR stores goods in plastic trays – which can be of various sizes – within a lightweight racking system that is limited in height only by the constraints of the building. Due to its modular construction, the OSR can be configured in a multitude of ways to suit existing building structures and various product weights and sizes.
The machine at AAH has a footprint of 36m by 7m and a height of 6m. There are two aisles, each with a vertical lift at the front end. There are three levels in each aisle and each level features multiple retrieval shuttles for the retrieval of up to 1,000 trays per hour. The shuttles interface with the elevators, which provide vertical transport of the trays to a conveyor system that feeds three order picking stations. The OSR control system supervises the location management, maintaining the inventory and taking care of functions such as FIFO and batch tracking. Initially built to hold 6000 SKUs, the OSR at AAH can be upgraded and will eventually hold nearer to 8000 SKUs. In the AAH configuration, goods are stored in 12,600 plastic trays which can be subdivided, with up to 4 compartments per tray. The maximum tote weight is 15kg, although this can be up to 32kg in other configurations. As, even among the slow-movers, there are always some lines that move faster than others, the OSR can allocate multiple trays to ‘fast’ slow-movers to accommodate them.
Items required for an order are anticipated by the computer control system, which instructs the OSR to retrieve the relevant trays in a sequence that matches the arrival of the pick-to totes at the pick stations. At appropriate times, the system is run in reverse to re-stock the trays as indicated by the computer control system, again using pick-by-light technology. With the comparatively low tray weights, the system is highly energy-efficient.