A production bottleneck is the process step, resource, machine, labor skill, material flow, or information handoff that limits the output of a manufacturing process. It is the point where demand on capacity exceeds available capacity, causing work to queue and constraining overall throughput.
In manufacturing operations, bottlenecks are commonly identified through signals such as growing work in process, missed schedule dates, low downstream utilization, long queue times, or repeated expediting. They may occur on the shop floor, such as at a specialized inspection station, or in supporting workflows, such as engineering review, quality disposition, material kitting, or system approvals.
A bottleneck should not be confused with any isolated delay. A temporary equipment stoppage or late material delivery may disrupt production, but it becomes a bottleneck when it repeatedly governs the rate of flow for the broader process. In lean manufacturing and theory of constraints contexts, the bottleneck is often treated as the constraint that determines how much the system can produce until capacity, sequencing, staffing, or process design changes.