A work order (also called a production order or manufacturing order) is an authorized document that instructs the shop floor to produce a specified quantity of an item by a certain date. In MRP-driven manufacturing, work orders originate as planned orders that a planner reviews and releases for execution.
At User Solutions we see the work order as the bridge between planning and execution. Plans live in the MRP system; work orders live on the shop floor. The quality of that bridge determines whether production runs smoothly or descends into chaos.
How Work Orders Work
The work order lifecycle follows a clear progression:
1. Creation
MRP generates a planned order when net requirements are positive. The planner reviews the planned order, verifies material availability and capacity, and releases it as a work order.
2. Material Allocation
Upon release, the system allocates (reserves) components from inventory per the BOM. If materials are short, the work order may be held until scheduled receipts arrive.
3. Scheduling
The work order's routing — its sequence of operations — is loaded into the scheduling system. Each operation is assigned to a work center with a start and finish time.
4. Execution
The shop floor processes operations in sequence. Operators report start times, completion times, quantities produced, and any scrap or rework.
5. Completion
When all operations are finished and quality inspection is passed, the work order is closed. Finished goods are received into inventory.
Work Order Example
A manufacturer releases Work Order WO-9050 for 75 units of Assembly PLT-800 (precision plate assembly):
| Field | Value |
|---|---|
| Work Order | WO-9050 |
| Part Number | PLT-800 |
| Quantity | 75 |
| Release Date | Monday, Week 10 |
| Due Date | Friday, Week 11 |
Routing:
| Op# | Work Center | Description | Setup (hr) | Run/Unit (hr) | Total (hr) |
|---|---|---|---|---|---|
| 10 | CNC Mill | Machine base plate | 1.5 | 0.20 | 16.5 |
| 20 | Drill Press | Drill mounting holes | 0.5 | 0.08 | 6.5 |
| 30 | Deburr | Hand deburr | 0.0 | 0.05 | 3.75 |
| 40 | Assembly | Install inserts + fasteners | 0.5 | 0.15 | 11.75 |
| 50 | QC Inspect | Final inspection | 0.0 | 0.10 | 7.5 |
Material allocation:
- 75 aluminum plates (on hand: 80 — allocated)
- 300 threaded inserts (on hand: 250 — short 50, PO arriving Wednesday)
- 225 fasteners (on hand: 400 — allocated)
The scheduling system (Resource Manager DB) sequences WO-9050 on the CNC Mill starting Tuesday (after the threaded inserts arrive) and calculates that all 5 operations will complete by Thursday of Week 11 — one day ahead of the due date.
Why Work Orders Matter for Scheduling
They are what gets scheduled. Scheduling software operates on work orders. Without released work orders with accurate routings, there is nothing to schedule.
They drive shop floor visibility. The status of each work order operation — not started, in process, complete — tells the planner and supervisor exactly where production stands. This visibility is essential for managing priorities and communicating delivery dates.
They capture actual performance data. Work order completions record actual setup times, run times, quantities, and scrap. This data feeds back into planning parameters, improving future schedule accuracy — the essence of closed-loop MRP.
They connect material and capacity. A work order links what to make (BOM) with how to make it (routing) and when to make it (schedule). All three must align for successful execution.
Excessive open work orders signal problems. If the number of released work orders far exceeds what the shop can process, the floor becomes congested with WIP. This increases lead times, confuses priorities, and reduces throughput — a problem finite capacity scheduling directly addresses.
Related Terms
- Planned Order — The MRP recommendation that becomes a work order when released by the planner.
- Purchase Order — The external procurement counterpart to an internal work order.
- Yield — The ratio of good output to total input on a work order, used to adjust future order quantities.
FAQ
A work order authorizes internal production — making something in your own facility using your machines and labor. A purchase order authorizes external procurement — buying something from a supplier. Both originate from MRP planned orders but follow different execution paths.
A typical work order includes the part number, quantity to produce, start and due dates, routing (sequence of operations with work centers and standard times), bill of materials (components needed), material allocation status, and any special instructions like quality requirements or customer specifications.
Work order status tells the scheduler what is actionable. Planned orders are suggestions. Firm planned orders are locked but not released. Released orders are active — materials allocated, ready to schedule on machines. In-process orders have started production. Completed orders are done. Only released and in-process orders appear on the active shop floor schedule.
This term is part of the Manufacturing Glossary. For a deep dive into material planning, see our MRP Guide.
Frequently Asked Questions
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User Solutions has been developing production planning and scheduling software for manufacturers since 1991. Our team combines 35+ years of manufacturing software expertise with deep industry knowledge to help factories optimize their operations.
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