Rolling paper rolls

Green Bay Packaging Inc. specializes in individual corrugated cardboard packaging, folding cartons and self-adhesive labels. More than 3,000 employees work for the Green Bay Wisconsin-based company at locations in 15 US states and Mexico. A new high-bay warehouse for paper rolls and dispatchable pallet goods was built as part of a plant expansion at Green Bay's Labelstock Division in Wisconsin. It is directly connected to the existing coating and cutting systems as well as to the new production areas using automated guided vehicles (AGV). The abbreviation AGV stands for Automated Guided Vehicles.

A particular challenge for the general contractor Hörmann Logistik was the transport and handling of a wide variety of load units weighing up to 5 tons. With several innovative developments, such as the various roller manipulators, slave board lowering devices, special AGVs with mandrel pick-up and cross-distribution trolleys with powercap technology, Hörmann Logistik met all project requirements. This also includes the fully flexible storage and retrieval strategies of the two-aisle high-bay warehouse with the three storage and retrieval machines.

Facts in figures

• Two-aisle high-bay warehouse in silo design
• Dimensions 176 x 26 x 25 m (L x W x H)
• Storage double-deep to 6-deep
• Storage of a wide variety of pallet types (one-way pallets)
• Storage capacity 12,800 pallets or 6,370 rolls
• 3 automatic storage and retrieval machines (aisle-bound) with two channel vehicles each
• Extensive conveyor technology, measurement of pallets
• 3 automatic roll handling gantries, two each fully redundant
• 4 AGVs for horizontal roll transport (5 tons)
• 3 AGVs with special pick-up (mandrel) for cut customer rolls
• Distribution trolley for crossing forklift traffic routes with Powercap technology
• Hi LIS warehouse management and control technology, system visualization

Construction of the new high-bay warehouse at Green Bay Packaging began in April 2014, with productive operation commencing in stages from May 2015 and being completed in 2016. The realization and commissioning was permanently accompanied and supervised by a Hörmann logistics team on site. Picture: Hörmann Logistics

The following targets were agreed:

• Mixed storage of paper rolls and finished goods on pallets
• Maximum redundancy and highly available systems
• Fully automated processes
• Just-in-time supply to production
• Gentle handling

Concept and implementation

To enable maximum storage capacity and flexibility, the new high-bay warehouse from Hörmann Logistik was designed as a two-aisle channel warehouse. In each storage channel, both 5-ton paper rolls and different pallet types with finished goods can be stored. One aisle of the high-bay warehouse (HBW) is equipped with two storage and retrieval machines (SRMs) on one track and one aisle with one SRM. The stacker cranes are each equipped with two channel vehicles that can extend individually (for smaller pallets) or together (for system pallets for heavy rolls). The middle racking unit can be operated from both aisles, thus ensuring a redundant supply of rolls for production.

Mandrel AGV for slit rolls

The packing area has been set up separately from the slitter rewinders to ensure flexible and effective compilation of customer pallets. In some cases, the finished rolls from several slitters are brought together on a customer pallet here. As the load handling device required for automatic transport was not available on the market, Hörmann Logistik developed a special solution in cooperation with the manufacturer. This innovative mandrel AGV is able to pick up a set of cut rolls of 1,400 mm roll width and 2 t weight directly from the slitter rewinder and deliver them fully automatically to many different pick-up points in the packaging. In this way, slitting and packaging are decoupled in terms of time and the special customer rolls can be picked without multiple handling.

The shelves have different depths: for rolls of 2, 4 or 6 pallets in order to react flexibly to different article quantities. For finished goods, there are more pallets in the compartment if they have smaller dimensions. The widths of the storage channels also vary between 1,000 mm and 2,200 mm. This results in better space utilization with different dimensions. All storage and retrieval machines are equipped with a self-learning compartment fine positioning system, which allows the channels to be approached with millimetre precision.

Cross-distribution trolley with integrated Powercap technology. Picture: Hörmann Logistics

In the incoming goods department, the raw material reels are manually placed on a floor-level centering station and then placed on the system pallet using a line gantry. The roll is measured and compared with the data notified by the customer's computer. The stacker crane then stores the roll.

Interaction of software, stacker crane, conveyor technology and automated guided vehicle system

When the production department requires raw materials, it requests a selection of reels via the Hörmann intra Logistics System Hi LIS, from which Hi LIS determines the one that is most easily and quickly accessible for the SRMs. This avoids the relocations that occur with other channel warehouses. Once the SRM has retrieved the reel specified by Hi LIS, it is transported to another gantry using conveyor technology. This removes it from the system pallet and sets the roll down for an automatic guided vehicle (AGV). The AGV then transports the roll directly to the skate of the unwinder in production. The finished coated rolls are returned to the warehouse in reverse order using the same technology. The Hörmann intra Logistics System Hi LIS manages and controls all material flow processes and communicates with the Green Bay host via an interface. In order to optimize the material flow, Hi LIS stores the raw material in different areas according to the systems to be supplied in the HBW: These storage strategies prevent the two SRMs in an aisle from obstructing each other while optimizing travel times. The Hi-LIS visualization ensures permanent transparency and rapid fault diagnosis in the event of a malfunction.

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