Engineering change notice (ECN): revising BOMs without chaos

What an ECN is

An Engineering Change Notice (ECN) — also called an engineering change note or order — is the controlled procedure for revising a released BOM or process. Because a released definition is exactly what the shop floor is building against, it cannot be changed casually: an ECN raises the change against an item or BOM, has it approved, and releases it so the revised definition becomes the active one — while every superseded revision stays traceable. It is how a plant changes a design without losing the record of what the design used to be.

In Fast Production Software the ECN runs on its own change shell and change dashboard, separate from day-to-day authoring, so a change is a deliberate, visible event rather than an edit someone made on a Tuesday. That separation is the whole point: the moment a BOM is released, changing it is an engineering decision with a paper trail, not a spreadsheet correction.

Why you can't just edit a released BOM

A released BOM is the single definition that open work orders explode against for material and cost. Editing it directly does three kinds of quiet damage:

• It changes what the floor is building — a silent edit can alter material or quantity on jobs already in progress, with nobody told.
• It breaks traceability — once the old revision is overwritten, you can no longer say which definition built a past lot.
• It corrupts costing — consumption-versus-BOM variance becomes meaningless if the standard it compares against has silently moved.

The ECN forces the change through raise-approve-release so it is authorised, dated and reversible in the record. That is the difference between a controlled engineering record and an editable spreadsheet — and it is precisely what a customer audit or a field-failure investigation depends on.

The three steps: raise, approve, release

An ECN runs in three controlled steps, and each is a deliberate gate:

The value of three steps rather than one edit is accountability at each gate: someone raised it for a reason, someone approved it, and the release is dated. In Fast Production this runs on the change dashboard, so open changes and their status are visible in one place rather than scattered across inboxes.

Assessing impact with where-used

Before an ECN is approved, someone needs to know its blast radius. That is what a where-used check is for: it lists every parent BOM and, by extension, every product that consumes the component being changed. Change a fastener used in one part and where-used confirms it is only one part; change a grade of raw material used across a dozen parts and where-used shows all twelve before you commit. Running where-used as part of the ECN review is how a plant avoids fixing one product and unknowingly breaking three others — it turns the change from a local edit into a scoped, understood decision.

What happens to open work orders

The question every planner asks about an ECN is: what about the jobs already running? The answer is deliberate. An ECN releases the revised definition for new work orders, but work orders already open were exploded against the previous revision and carry their own bill and their own material issue. That is by design — a job in progress should not have its material definition change underneath it mid-run.

So the plant decides, case by case, whether an open order runs to completion on the old revision or is short-closed and re-raised on the new one. A minor change might let running jobs finish on the old bill; a safety-critical change might require short-closing them and re-issuing. Either way the record shows which revision each order used — which is the whole point of doing it under control.

Supersession and traceability

When an ECN is released, the previous revision is not deleted — it is superseded and retained through the document-status history. The revised BOM or process becomes active for new orders, but the record still shows the old revision, when it changed, and through which ECN. That is what lets an automotive or engineered-part maker answer the audit question that arrives years later: which revision of the bill built this lot, and what change moved it to the next one? Supersession rather than deletion is the difference between a definition you can trust historically and one that only tells you about today.

How Fast Production runs the ECN

Fast Production Software implements engineering change as a real, exercised module on the shared Fast Suite platform:

Because it runs on the shared platform, a change flows cleanly through BOM, process, work orders and costing on one engine — the manufacturing core behind deployments such as Nikhtish Engineering and Solidus Hi-Tech.

Frequently asked questions