Lead time is the total calendar or working time from when a job is released to production to when it is complete and ready to deliver. It bundles every step's setup and run time, the queue and transit time between operations, and any curing or shipping tail after the last machine step. Lead time is what a delivery promise rests on, and a realistic one comes from scheduling the job against real capacity rather than applying a fixed rule of thumb.
This entry defines lead time and shows how it behaves inside EDGEBIC by User Solutions. For the wider index of planning terms, see the manufacturing glossary, and for the delivery tail that lands at the end of it, read what is end-item lead time in scheduling.
How it works
The everyday version is the pizza shop's forty-five minutes from order to door. That figure is not just the baking time. It includes the wait in the queue behind other orders, the prep, the bake, the boxing, and the drive. Manufacturing lead time is the same total elapsed span for a job, from release to a part the customer can actually receive.
Two things make lead time longer than the sum of the productive hours. First, waiting: parts queue in front of busy machines, sit in inspection buffers, and travel to and from outside vendors. Those gaps are real elapsed time even though no work happens during them. Second, the tail: many parts are not deliverable the instant they come off the last machine, because paint cures, adhesives set, or the item still has to ship. That delivery tail is part of lead time even though it uses no machine capacity.
The most accurate lead time is not a fixed number but a scheduled one. When you place the job's steps into real, finite capacity, the finish date reflects the current load: busy periods stretch the lead time honestly, quiet periods shorten it. A static lead time cannot do that, so it over-promises when the plant is full and wastes time when it is empty.
A concrete example
A job routes through four operations, then cures for two days before delivery. The productive hours total about sixteen, which a naive estimate might call two shifts. But the real lead time is longer.
The first operation waits a day in queue behind other jobs on a busy machine. Between two steps the parts go to an outside vendor for plating, three working days out and back. After the final operation, the part cures for two calendar days before it is delivery-ready. Add it up and the honest lead time is well over a week, not two shifts, and almost none of the difference is machine time. It is queue, transit, and the curing tail. A promise built on the sixteen productive hours would miss badly; a promise built on the scheduled dates, including the tail, holds.
How EDGEBIC uses it
EDGEBIC produces lead time as an output of scheduling rather than a fixed input. When the engine places a job's steps into finite capacity, the span from the job's start to its delivery-ready finish is the lead time, and it reflects the real queues, transit days, shift calendars, and machine load at the moment of the run. Because it is computed, not assumed, the lead time lengthens honestly when the plant is busy and shortens when it is not.
The delivery tail is modeled explicitly as an end-item lead time: a number of calendar days after the last work-center operation before the item is deliverable. It reserves time in front of the due date without consuming machine capacity, and it separates the moment the part physically exists from the date it can ship, so lateness is judged against the true delivery-ready date. The same scheduling logic powers quote simulation, where running a prospective order through the engine returns a what-if promise date grounded in current capacity instead of a blanket rule.
To understand the delivery tail in detail, continue with what is end-item lead time in scheduling. For the between-steps buffer that adds to lead time, read what is queue time in manufacturing scheduling. And for the engine that computes lead time against real capacity, see what is advanced planning and scheduling.
Expert Q&A: Deep Dive
Q: We quote a flat four-week lead time on everything, but some jobs finish early and others miss. How do we tighten that?
A: Replace the flat figure with a scheduled lead time. Run each quote through the scheduling engine so it places the job's steps into your real capacity and returns a finish date based on current load, not a blanket rule. Busy weeks produce a longer, honest promise; quiet weeks a shorter one. The flat four weeks is an average that is wrong in both directions, over-promising when the plant is full and leaving money on the table when it is empty. A simulated finish date is specific to the job and the moment.
Q: Our part comes off the last machine but is not deliverable for two days while it cures. Does that count as lead time?
A: Yes. The delivery-ready date, not the off-the-machine date, is what the customer cares about, so the curing tail is part of the lead time. Model it as an end-item lead-time tail: a number of calendar days after the last work-center operation before the item is deliverable. It consumes no machine capacity but shifts the job's true completion, and lateness should be measured against that delivery-ready date. Ignoring the tail makes every job with a cure or ship step look two days more on-time than it really is.
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