Automated Order Fulfillment – Distribution Center Simulation

Design Conveyor Systems (DCS) was contracted to design an automated palletization subsystem inside a new state of the art distribution center for a leading pet supply company.  DCS partnered with MOSIMTEC to develop an AnyLogic simulation of the palletization subsystem to ensure the system can perform at its contracted levels.  The simulation model helped test the throughput of the design and identify potential weaknesses in the operational policies.  Findings helped drive operational decisions during the design phase, instead of after implementation, when the cost of changes would be extremely high.

Pallets arrive from manufacturers with single SKU bags of dog food, cat food, cat litter, and other bagged products.  Since stores rarely need an entire single-SKU pallet, the automated subsystem builds multi-SKU pallets to ship to stores.  The subsystem is a completely automated grid with eight independent zones, each zone with a dedicated overhead crane.  Up to 60 manufacturer pallets are placed in each zone for the gantry crane to build mixed-SKU store pallets.  All pallet moves within the grid are executed by Autonomous Mobile Robots (AMRs).  Completed store pallets are plastic wrapped, labeled, and brought to an outgoing cell.

The flexibility of AnyLogic allowed MOSIMTEC to create a flexible Excel based user interface.  This allowed DCS to change grid configuration, SKU definitions, pallet assignment locations, movement speeds, and AMR counts.  Examples of questions answered by the modeling engagement included time to complete store pallets for a given day, number of AMRs needed, system bottlenecks, impact of system failures, and impact of induction and take away break times.  The model analysis identified a potential imbalance in the usage of the eight zones driven by manufacturer SKU to zone assignments.  The analysis also suggested that the number of planned AMRs may be able to be reduced without compromising throughput.