OPS.11.1:5.1 - Two departments share one operator
Three units need preparation and then inspection. Each step takes two hours of one operator’s attention. Preparation and inspection are shown as separate departments, each with an eight-hour day. A departmental summary assigns six hours to each and appears to permit same-day completion.
Recovering the resource references shows that the same person performs both steps. The work needs twelve operator-hours. This excludes completion within eight hours under the stated arrangement, without needing a detailed simulation. Preparing and inspecting each unit in turn attains twelve hours if no other restrictions apply.
Now inspection changes: its first half-hour requires the operator, followed by one and a half hours of unattended machine operation. The operator demand becomes 7.5 hours, but that total alone does not prove an eight-hour schedule. With one inspection machine, a feasible sequence is:
| Unit | Preparation | Inspection with operator | Inspection unattended | Completion |
|---|---|---|---|---|
| 1 | 0–2 | 2–2.5 | 2.5–4 | 4 |
| 2 | 2.5–4.5 | 4.5–5 | 5–6.5 | 6.5 |
| 3 | 5–7 | 7–7.5 | 7.5–9 | 9 |
The machine’s final unattended interval extends beyond the operator’s work. Completion by hour eight is still impossible: preparing all three units and starting all three inspections needs 7.5 operator-hours, followed by the last inspection’s 1.5 unattended hours. The schedule attains that nine-hour bound. Separating resource occupancy from elapsed processing gives the next design question: what can shorten or overlap that final tail?