Most Lead Time Is Queue Time — Not Machining Time
Workflow optimization in manufacturing addresses the movement of jobs between operations — how work is scheduled, sequenced, batched, and routed from raw material through shipping. In a typical CNC job shop, actual machining time represents only 5-15% of total lead time. The remaining 85-95% is queue time: parts sitting in tote bins waiting for the next machine, the next operator, or the next inspection step.
This queue time is not caused by slow machines. It is caused by how work is organized. Jobs are released to the floor in large batches because that minimizes setups. But large batches create long queues at downstream operations, which extend lead times, increase work-in-process (WIP) inventory, and make the shop floor harder to manage. One late job at a bottleneck machine cascades delays to every job behind it.
Workflow optimization attacks these systemic problems. Using principles from Theory of Constraints (TOC) and lean manufacturing, we redesign the rules that govern how work moves through your facility. The constraint machine — the one that limits overall output — becomes the pacemaker. Everything else subordinates to keeping that machine running productive parts in the right sequence.
The result is shorter lead times, lower WIP, fewer expedited jobs, and a shop floor that runs with predictable rhythm rather than constant firefighting. Dr. Eliyahu Goldratt's Theory of Constraints framework, originally published in "The Goal," has been applied to thousands of manufacturing operations worldwide — and its principles are particularly powerful in high-mix CNC environments where scheduling complexity is highest.