Plan on Lead Time vs Require on Hand: the Material Availability Choice

A product's Material Availability setting decides one thing: whether a job whose material has no covering supply gets a date based on an assumption, or gets reported as a shortage instead. It is a per-item override of the site policy, with three values: Use site policy, Plan on lead time, and Require on hand. The choice looks small on the product form and it changes what a schedule is claiming.

The failure mode this setting exists to address

Start with what happens by default, because it is the part people are surprised by.

A job needs a component. No purchase-order line covers the shortfall. EDGEBIC does not invent a peg and does not silently pretend the material is there. It writes a loud warning into the scheduling diagnostics log, naming the job, the component and the shortfall quantity, and telling you to raise a purchase order or the job will be short. Then it falls back to lead-time behavior: the material bar runs for the item's lead time, and the job schedules on from there.

The result is a plan, not a promise. The dates assume material nobody has ordered.

What makes this genuinely dangerous is that the fallback is quiet on the planning surfaces. No amber marker appears, because there is nothing to wait on. An unordered material looks exactly like a material you already have. The warning is real and it is in the diagnostics log, but the Gantt does not carry it.

What each value does

Use site policy defers to whatever the site is configured to do. This is the right value for the overwhelming majority of items, because a policy you set once and apply everywhere is easier to reason about than a hundred individual decisions.

Plan on lead time is the permissive behavior described above. A job without covering supply still gets a date, computed from the item's lead time. You keep a complete, workable plan, and you accept that some of its dates rest on orders that have not been placed.

Require on hand is the strict behavior. A job that cannot be covered from the rack is reported as a material shortage rather than planned against an assumption. You get fewer dates, and the ones you get are backed by stock that physically exists.

Why the choice belongs on the item, not only on the site

Because the cost of a wrong assumption is not uniform.

For a stock fastener you reorder every week, an assumed lead-time date is almost always right, and a shortage report for it would be noise that trains people to ignore shortage reports. For a casting with a long lead time and one supplier, the same assumption is the difference between a promise you keep and one you do not.

Making Material Availability a per-item override is what lets both be true at once. You set a sane site policy for the bulk of the catalog, then override the handful of items where being wrong is expensive. That is the same shape as the rest of the engine, where the general rule is set once and the exceptions are named explicitly, the way a material step gates an operation rather than consuming capacity it does not need.

The routine that catches the rest

The setting is not a substitute for looking. Because lead-time fallback is quiet, the check has to be deliberate.

Open the Material Pegging report. It lists jobs that are pegged, so a job you expected to see and do not is a job with no covering supply. Cross-check the Scheduled Receipts report for that material: nothing inbound at all is your answer. Then raise the purchase order, set a realistic promised date, set the status to Open, and reschedule. The job now pegs honestly, and it probably moves later, which is the entire point.

Making Scheduled Receipts part of the routine before publishing a schedule is the habit that closes the gap. What material pegging means in EDGEBIC covers how the pegs themselves are formed, and how a plan absorbs a late material delivery covers what happens when the supply exists but slips.

Why model it this way

There is a version of this that would be worse in both directions, and the design avoids both.

A scheduler that always assumed material would produce beautiful, useless plans. A scheduler that always demanded stock on hand would refuse to plan most of the work in most plants, because most plants schedule against supply that is inbound rather than received. Neither extreme is a plan you can run a shop with.

The answer is to make the assumption explicit and adjustable, to log it loudly when it is being made, and to let the item decide. That is what the three values give you: a default that keeps the plan complete, a strict mode for the items that deserve it, and a diagnostics log that never lets the assumption go unrecorded even when the Gantt looks calm.

For how material planning and finite scheduling relate as two passes over the same data, the complete scheduling engine guide shows where the material pass sits. To see the setting change a date on your own long-lead items, explore EDGEBIC or bring your data to a demo.