Production Operations Management
What the exam tests
This domain covers turning released orders into a feasible sequence: finite and infinite scheduling, dispatching rules, takt, bottlenecks, work-in-process control, setup effects, and cycle-time management.
Core rules
- Takt time = available production time / customer demand. It sets the pace, not the actual machine cycle.
- Finite scheduling respects capacity; infinite scheduling ignores capacity and can produce an infeasible plan.
- Dispatching rules such as earliest due date, first-in-first-out, shortest setup, and critical ratio trade due-date performance against throughput.
- A bottleneck limits system output. Non-bottleneck efficiency gains often increase WIP rather than throughput.
- Releasing more work than the line can absorb increases queue time and lead time.
Worked example
A cell has 420 available minutes per shift (25,200 seconds) and demand of 840 units. Takt = 25,200 / 840 = 30 seconds. The cell’s cycle time is 34 seconds, so demand cannot be met at current pace. Required improvement is 34 - 30 = 4 seconds per unit, or about 11.8%. Overtime could cover the gap, but the exam answer should identify the constraint first.
Traps
- Using machine efficiency instead of demand when calculating takt.
- Confusing cycle time (time per unit at a station) with lead time (total elapsed time).
- Optimizing a non-bottleneck and claiming system throughput improved.
- Ignoring setup and changeover when sequencing small lots.