Nonbottleneck

A nonbottleneck is a resource, process step, or work center in a system whose capacity is not the limiting factor for overall throughput. In manufacturing, services, and project management, the bottleneck is the element that constraints the rate at which the system can deliver outputs. Nonbottlenecks have greater capacity than the required flow rate, so they do not determine the system’s maximum throughput under current conditions.

In practice, nonbottlenecks may operate at or near their capacity, but they do not set the pace of production because the bottleneck’s slower rate governs the overall flow. The distinction can be context-dependent and may shift if demand or variability changes, causing another stage to become the bottleneck. Effective management of nonbottlenecks focuses on ensuring they receive adequate input, avoiding unnecessary delays or excess work-in-process that could accumulate upstream or downstream, and preventing them from starving the bottleneck with uneven scheduling.

Key characteristics include higher capacity relative to the system’s bottleneck, potential underutilization or balanced utilization aligned to bottleneck output, and a lower impact on overall throughput when disrupted. In techniques such as the Theory of Constraints, emphasis is placed on identifying and improving bottlenecks while coordinating nonbottlenecks to support smooth flow rather than constrain it.

Examples can include auxiliary machining stations in a factory, support functions in a service line, or parallel tasks in a project that do not limit completion time unless demand or variability changes.