Discrete Event Simulation (DES) and FlexSim Overview
📌 Discrete Event Simulation (DES) models processes that happen over time based on specific, distinct events (e.g., a person taking 4 seconds to move).
🖥️ FlexSim, established in 1979 and acquired by Autodesk in 2023, specializes in building detailed simulation models, offering expertise in throughput and bottleneck analysis.
🔗 A key differentiator in FlexSim is its Process Flow system, which uses a flowchart structure making complex models easier to understand, even for non-modelers.
🏢 FlexSim is utilized by major Fortune 500 companies, including Amazon, Toyota, and FedEx, to create digital twins and verify theoretical scenarios.

Theoretical Use Case: Optimizing an AGV Loop
🎯 The goal of the AGV loop scenario was to determine the exact number of Automated Guided Vehicles (AGVs) needed to meet a target throughput of 45 jobs per hour, thereby avoiding unnecessary capital expenditure.
🗺️ Model inputs required specifications such as facility layouts (like AutoCAD DWG files), AGV performance (acceleration, speed), station cycle times, and downtime information (MTBF/MTTR).
⚙️ FlexSim models accurately reflect 3D space, calculating travel time based on distance and speed (e.g., 2 feet apart at 1 ft/second takes 2 seconds).
📊 The model allows for detailed AGV pathing control, including stopping distances, traffic control, speeds, accelerations, and battery usage.

Experimentation and Results Analysis
🧪 Experimentation in FlexSim involves defining scenarios (different parameter sets, like varying AGV counts) and replications (running the scenario multiple times with different random seeds) to ensure statistically significant results.
📈 Key Performance Indicators (KPIs) generated automatically include mean values, confidence ratings (e.g., 95% or 99%), and box plots to identify outliers.
💡 In the AGV case, the analysis revealed that 11 AGVs achieved the target of 45 jobs/hour; using 12 or more slightly *decreased* throughput due to traffic issues.
🔄 The simulation process is iterative, allowing for further testing of variables like buffer space, station relocation, or changes in cycle time tolerances.

FlexSim Capabilities and Interfacing
🚫 FlexSim does not automatically detect bottlenecks; instead, utilization percentages (e.g., one station at 100%) or detailed interaction analysis must point to restrictions.
🚚 FlexSim supports numerous modules beyond AGVs, including robotics, ASRS systems, conveyors, GIS trucking navigation (for inter-facility transfers), and even fluid modeling in pipes.
🔗 The software supports emulation via a specific module to interface with real systems like PLCs (Programmable Logic Controllers), enabling the simulation to act as a true digital twin for testing control logic.

Key Points & Insights
➡️ DES is ideal for "if-then-else" modeling of discrete events over time, creating a functional digital twin of a facility or process.
➡️ The primary benefit of simulation modeling is cost avoidance by precisely determining the required number of assets (like AGVs) needed for operational targets.
➡️ When building models, clearly define the core question upfront (e.g., "How many AGVs are needed?") before collecting detailed specifications.
➡️ FlexSim's Process Flow functionality allows non-modelers familiar with flowcharts to effectively read and understand the logic within complex simulations.

📸 Video summarized with SummaryTube.com on Nov 14, 2025, 08:47 UTC