Why does the capacity lane matter?
A supplier response can look useful while solving the wrong problem. A temporary backlog, a delayed internal line, an awarded demand peak, a resilience requirement, and a failing incumbent require different boundaries, investments, ownership, and exit conditions.
The capacity profile should name the event before it names a new producer. That keeps a short-term bridge from becoming an uncontrolled permanent transfer and prevents a long-term second-source decision from being treated as emergency overflow.
Capacity strategy decision matrix
| Strategy | Best used when | Design question | End condition |
|---|---|---|---|
| Overflow | The baseline source remains viable but a bounded recurring workload exceeds it | Which stable work can move while authority remains clear? | Return, rebalance, or continue a defined allocation |
| Bridge | A planned internal line or supplier will be ready after a defined gap | What production basis must exist during the gap? | Controlled handback or transition at an explicit gate |
| Surge | Validated demand creates a temporary curve above the normal rate | Which resources and controls support each temporary step? | Return to the approved baseline after the demand event |
| Second source | Ongoing redundancy, resilience, or allocation flexibility is required | What qualification and equivalence evidence establish another path? | Maintained qualification and governed allocation |
| Supplier recovery | The current source is missing output, quality, or control expectations | Which root constraint should be contained, corrected, or transferred? | Verified recovery, replacement, or permanent work split |
When is overflow the right answer?
Overflow fits a stable product and recurring workload when the current line remains part of the operating model. The transferred work should be complete enough to schedule, execute, inspect, test, accept, and reconcile without creating competing product definitions.
The plan should specify the allocation rule, order ownership, material ownership, shared tooling, change authority, exception flow, capacity review cadence, and handback condition. Overflow is not a reason to create an informal shadow process.
What makes bridge production different?
Bridge production exists for a defined interval. Its design starts with the end. The parties should know what event closes the bridge, what evidence transfers back or forward, who owns residual material and tooling, and how open nonconformance or warranty responsibilities follow the product.
A bridge with no end condition can become an unplanned second source. A bridge with an unrealistic transfer date can create a second production interruption.
What does a qualified second source require?
A second source needs more than a matched part number. It needs a controlled baseline, approved inputs, equivalent work and acceptance, a change-governance model, retained records, and a deliberate plan for keeping the source current when the product changes.
Qualification should be proportional to the transferred risk. It should also define what must be repeated after a material, process, tool, site, software, test, or product change.
Seven questions that identify the lane
- Is the demand event temporary, recurring, or indefinite?
- Is the current source healthy, constrained, delayed, or in recovery?
- Which complete work package can move?
- How stable is the controlling configuration and documentation?
- What qualification and acceptance evidence will be required?
- Who owns material, tooling, changes, nonconformance, and release?
- What event ends, renews, or changes the arrangement?