Glossary · System coordination, integration and orchestration
Dispatch rule
Also known as: dispatching rule, priority rule
German: Dispositionsregel
In production scheduling, a dispatch rule is a rule that determines which waiting job a free resource processes next, based on attributes such as arrival order, due date, processing time or priority.
- System integration
In one sentence
A dispatch rule decides which waiting job a free machine or resource processes next, based on arrival, due date, duration or priority.
Example
The heat-treatment furnace uses earliest due date as its dispatch rule, but rush orders flagged by production planning always go first.
How it applies
- Operation: Dispatch rules make decisions at run time where a full schedule would be too rigid. Common rules include First in, first out (FIFO), Earliest due date (EDD) and shortest processing time.
- Engineering: Combine rules with constraints such as setup families, material shelf life or batch purity. Test rule changes in simulation before using them on a real line; small changes can shift throughput and lateness significantly.
- Documentation: Document the active dispatch rules and their exceptions in the MES configuration documentation, so that planners and operators understand why jobs run in a particular order.
Dispatch rule vs. job scheduling
Job scheduling plans a sequence of jobs ahead of time. A dispatch rule decides locally and at the moment a resource becomes free; it can be used on its own or to correct a schedule during execution.