# Engineering Change Order (ECO)

> Source: https://netray.co/glossary/engineering-change-order
> Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems.
> Section: Glossary

## Short answer

An engineering change order (ECO) is the formal, approved document that authorizes a change to a part, bill of materials, drawing or routing, defines when it takes effect, and says what happens to existing stock and open orders.

## Aliases

- ECO
- ECN
- Engineering Change Notice
- ECR

## Category

manufacturing

## Full Definition

An ECO starts as a request (ECR) describing a problem or improvement, goes through impact review by engineering, quality, purchasing and production, and is released as an order that changes released data. The ECO is what keeps a drawing revision, a BOM and a routing moving together instead of drifting apart.

Every ECO needs an effective point: by date, by serial or lot number, or by work order. It also needs a disposition for stock on hand and on order: use as is, rework, scrap, or return to supplier. Without a disposition, the change releases cleanly on paper while the floor keeps building the old revision.

In ERP the ECO usually lives outside the core planning tables. Infor LN has engineering change management in its Engineering Data Management area, SyteLine typically relies on item and BOM effectivity dates plus a custom or third-party change workflow, and NetSuite uses revision records or a PLM integration. Where the ECO lives matters because auditors in AS9100 and ISO 13485 environments expect traceable approval of every change.

An ECO is not a work order and not a purchase change. It changes the master data that later transactions read, so a bad ECO quietly corrupts every future planned and released order.

## Why It Matters

- Uncontrolled changes are a leading cause of building to the wrong revision, which means scrap, rework and customer escapes.
- Aerospace, medical and defense customers audit change history, approvals and effectivity as part of quality system reviews.
- A change that does not reach purchasing and open POs leaves suppliers shipping the old part after cutover.
- ECO cycle time directly slows new product introduction and corrective action closure.

## In Practice

A bracket changes from 3.0 mm to 3.5 mm stock. The ECO releases revision C of the drawing, replaces the raw material on the BOM effective at work order 4500, sets 120 pieces of rev B on hand to use as is for service orders only, and notifies purchasing to cancel the open PO for 3.0 mm bar. Missing any one of these steps is the usual failure.

## Faq

### What is the difference between an ECR, an ECN and an ECO?

**Answer:** An ECR is the request to consider a change. The ECO is the approved order that executes it. ECN, a change notice, is often used for the notification step or as a synonym for ECO depending on the company.

### Who approves an engineering change order?

**Answer:** A change board usually signs off, with engineering, quality, manufacturing, purchasing and sometimes the customer, depending on contract flow-down.

### Does ERP or PLM own the ECO?

**Answer:** In companies with PLM, the PLM system owns the ECO and releases the result to ERP. Without PLM, the ERP or a spreadsheet and paper workflow carries it, which is where control tends to fail.

## Search terms

engineering change order, what is an ECO, ECO vs ECN, engineering change process, engineering change management ERP, ECO in manufacturing, ECR ECO ECN difference

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