Taming Shopfloor Chaos:
A DES & Constraint Programming Hybrid

1. The Illusion of the Static Schedule

Most modern ERP and APS (Advanced Planning and Scheduling) systems rely on deterministic models. They generate a daily schedule assuming standard processing times, zero machine breakdowns, and perfect raw material availability. The moment a tool breaks or a setup takes 15 minutes longer than anticipated, the static schedule shatters. This stochastic noise leads to massive Work-in-Progress (WIP) buffers, delayed downstream logistics, and missed SLA targets.

2. The Hybrid Framework (DES + CP)

To optimize under uncertainty, Presolve Labs deploys a hybrid architecture. We pair a high-fidelity Discrete Event Simulation (DES)—acting as a digital twin of the shopfloor—with a lightning-fast Constraint Programming (CP) solver.

• Continuous "What-If" Probing The DES constantly runs thousands of Monte Carlo rollouts into the future, anticipating where stochastic bottlenecks (like queue build-ups) will occur before they happen in reality.
• Dynamic Re-Sequencing & Routing When the DES flags a high-probability bottleneck, the CP engine instantly recalculates optimal material routing and setup sequencing. It redirects AGVs and workpieces to alternative machines, minimizing setup teardowns and maximizing throughput.

3. Impact: WIP Reduction and Just-In-Time

The visual dashboard to the right demonstrates this shift. Under standard heuristic routing, workpieces blindly follow a fixed path to Machine 3, causing a cascading queue that blocks upstream operations.

By deploying the DES-CP hybrid, the system achieves true Just-In-Time (JIT) flow. Inventory holding costs plummet as WIP is reduced by over 40%. Because parts reliably exit the shopfloor exactly when needed, follow-up logistics can operate with tighter margins, raising On-Time In-Full (OTIF) delivery metrics to 99%+.