A work order is the primary unit of work on a manufacturing shop floor. It specifies what needs to be made, how many, what materials to use, which operations to perform, and in what sequence. Work orders are typically generated from sales orders or MRP planning and released to the floor when materials and capacity are available.
Each work order follows a routing — a sequence of operations (machining, assembly, inspection, etc.) that must be completed. As the job moves through each operation, the work order accumulates labor time, material consumption, and quality data that becomes the production record.
In regulated industries like aerospace and medical devices, work orders carry additional requirements: serialization, lot traceability, operator certifications, and inspection hold points. The work order becomes the traveler — a living document that proves every step was performed correctly.