Purpose
Planning of the production phase-out: for each stage and quarter, the cost-optimal combination of shifts, machines and workers that still covers the declining volume.
Background
Based on the RampDownPlanner desktop application (Python, PySide6) from the production engineering seminar SS2026. Master data, volumes and costs in this demo are simulated.
Procedure
- Configure volume, capacity and cost parameters on the left or keep the defaults.
- Work through tabs 1 to 4 to follow the planning from volume to costs.
- Use tab 5 to find the best shutdown quarter per stage and to compare saved scenarios.
Volume plan
Volume per quarter until end of production
Capacity plan
Optimal configuration per stage and quarter
Quarter detail
All configuration options of one quarter
Costs
Cost components and cost per unit
Scenarios
Shutdown check and saved planning variants
Optimisation method
For every stage and quarter, all combinations of 1 to 3 shifts, 1 to the maximum number of machines and the possible worker counts per shift are evaluated. The capacity is output per shift-week × shifts × production weeks. Among all feasible combinations, the one with the lowest total cost is selected (brute-force search, as in the original).
Suggested experiments
- Steeper decline: Increase the volume decline to 30 %. The cost per unit in the last quarter rises sharply, and in tab 5 the best shutdown quarters move about two years earlier.
- Outsourcing: Open tab 5, apply the recommended shutdown for heat treatment and save the result as a scenario.
- Utilisation limit: Lower the maximum utilisation to 85 %. In the first quarters some stages no longer have enough capacity (red cells in tab 2).
- Sunk machine costs: Set the fixed costs of a parked machine to 100 %. Reducing machines then saves nothing; the plan keeps more machines with fewer shifts, and shutdowns become worthwhile earlier.
Step 1: Volume to be produced per quarter until the end of production.
Volume per quarter
Units per quarter. The volume declines annually and drops to zero at the end of production.
Step 2: Cost-optimal configuration per stage and quarter.
Configuration per stage and quarter
Each cell: shifts (S) · machines (M), below the utilisation. Select a cell to open the quarter detail.
Interpretation
As the volume declines, the optimisation first reduces workers and shifts, then machines. Over-capacity occurs when even the smallest configuration exceeds the remaining volume; fixed costs then dominate the cost per unit.
Headcount per quarter
Direct workers across all shifts plus indirect staff.
Step 3: Configuration and costs of all stages in one quarter.
Stages in this quarter
Optimal configuration, capacity, utilisation and quarterly costs per stage.
Configuration options of the selected stage
The eight cheapest feasible combinations, i.e. those that cover the volume within the maximum utilisation. The first one is the optimum.
Interpretation
Configurations that are cheaper than the optimum do not appear because their capacity is too small. A small difference between the optimum and the next options indicates that the decision is not sensitive.
Manual configuration
Choose a configuration for the selected stage and compare it with the optimum.
Step 4: Development of costs over the ramp-down.
Cost components per quarter
Stacked quarterly costs in € thousand.
Cost per unit
Total quarterly cost ÷ volume. Rises when fixed costs are spread over fewer units.
Table by year
Step 5: Shutdown check per stage and comparison of saved planning scenarios.
Shutdown check
For each stage, every possible shutdown quarter is evaluated with all other parameters unchanged. The table shows the cheapest quarter; Apply transfers it to the parameters.
Method
A shutdown saves the stage's personnel, machine and variable costs and its indirect staff, but its volume is then bought externally at a fixed price per unit. While the volume is high, in-house production is cheaper; as the volume falls, fixed costs are spread over fewer units and external sourcing becomes cheaper. The best shutdown quarter is where the cumulative saving is largest.
Cost effect of the shutdown quarter
Total cost over the horizon if the stage is shut down in the given quarter, relative to no shutdown. Below zero: the shutdown saves money.
Saved scenarios
Change parameters on the left, save, repeat. Changes lists the deviations from the defaults; "Current" reflects the parameters on the left.
Cumulative cost difference to the current plan
One line per saved scenario. Above zero: the scenario is more expensive than the current parameters up to that quarter.