Anonymous Large Brewer

During the conceptual design stage of a new automated storage and retrieval system (AS/RS) at the Eichhof Brewery in Luzern, Switzerland, engineers faced a critical planning challenge: validating whether the proposed distribution system could handle operational demands before construction began. The system involved a conveyor network exceeding 250 meters in length with more than 150 drive units spanning five levels, processing up to 1,800 pallets per day. In high-throughput food and beverage operations, undetected bottlenecks discovered post-installation are extremely costly to remediate. The team needed to analyze strategies to increase pair pallet movement of narrow-aisle cranes and stress-test the system under breakdown scenarios before committing to the final design.

Rockwell Automation's Arena Simulation Software was used to build a detailed digital twin of the entire distribution system. The model was decomposed into interconnected submodels representing each physical subsystem: a core conveyor-elevator network, rail-guided vehicles, and multiple narrow-aisle cranes operating across sectioned aisles. Pallets moved in pairs from a main scanner level via two elevators to two upper levels, feeding four crane pick-up points. Each aisle was divided into two sections, each with its own crane and asymmetric pickup and drop-off stations. Arena's Input and Output Analyzers were used for statistical analysis of real operational data, while animated dashboards tracked crane utilization histograms, pallet counts by conveyor section, and congestion levels across rail-guided vehicles. Breakdown scenarios — including single crane failures and elevator outages — were explicitly modeled to evaluate system resilience.

More than 500 simulation runs revealed findings that surprised both the end user and the main contractor. While the overall system design met required throughput, several unexpected bottlenecks emerged at specific operational periods:

• Narrow-aisle cranes were underutilized, indicating over-provisioning in crane capacity
• Rail-guided vehicle QVW2 was identified as a throughput bottleneck unless velocity could be increased
• Elevators SF3/SF4 became critical single points of failure during breakdowns of adjacent units, requiring dedicated breakdown strategies
• Elevator SF1 would constrain throughput if restricted to single-pallet handling
• One scanner (I-point) proved sufficient, but pair-building strategies needed to be formalized
• During breakdown conditions, alternating intake from production, train, and truck sources was necessary to sustain maximum throughput

• Simulate before you build: Digital twin modeling during conceptual design catches bottlenecks that only appear under realistic load conditions — post-installation fixes are far more expensive.
• Breakdown scenarios are as important as steady-state runs: Stress-testing individual component failures (cranes, elevators) revealed cascade effects that steady-state analysis would miss.
• High-level utilization metrics can mislead: Cranes appeared adequately specified on paper but were underutilized in simulation — freeing budget for higher-priority constraints like rail-guided vehicle speed.
• 500+ runs builds statistical confidence: A large simulation run count is necessary in complex, multi-variable AS/RS environments to surface time-of-day demand patterns.
• Pair-pallet movement strategies require explicit modeling: Pallet pairing logic is a non-trivial constraint that must be designed into the simulation, not assumed.