Mar 13, 2026
BOM & Change Management
What Is Engineering Change Management? ECM Explained
What Is Engineering Change Management? ECM Explained
What Is Engineering Change Management?
Engineering Change Management (ECM) is the formal process by which manufacturers evaluate, approve, implement, and document modifications to product designs, materials, specifications, or manufacturing processes. It ensures that every change is reviewed by the right people, implemented correctly, and fully traceable—so that the actual product matches its authoritative design record.
Key Fact | Detail |
|---|---|
Core artifact | Engineering Change Order (ECO) |
Without ECM | Unapproved changes reach production; compliance failures; warranty costs |
Governed by | PLM system (Windchill, Teamcenter), plus formal procedures |
Regulatory drivers | AS9100, ISO 9001, FDA 21 CFR Part 11, ITAR |
Key roles | Design Engineer, Change Board, Manufacturing Engineering, Quality |
Average ECO cycle time | 2–8 weeks (manual); 2–5 days (automated via PLM) |
The Engineering Change Order (ECO) Process
The ECO is the fundamental unit of engineering change management. A complete ECO process follows these stages:
Change Request (CR) — Anyone in the organization identifies a need for change (design flaw, customer feedback, cost reduction, obsolescence). A formal change request is submitted with problem description and urgency classification.
Impact Assessment — Engineering evaluates: which parts/assemblies are affected? What is the production impact? What is the cost? Are there supplier implications? In PLM, this leverages "where used" analysis to identify all affected items.
Change Proposal — Engineering documents the proposed solution, including redlined drawings, updated BOM, revised specifications, and any required supplier changes.
Change Review Board (CRB) — A cross-functional team (engineering, manufacturing, quality, procurement) reviews the proposal. Complex changes may require multiple review cycles.
Approval — The CRB approves, rejects, or returns the ECO for revision. In PLM systems, digital signatures capture the approval record.
Implementation — Approved changes are implemented: CAD files are updated, BOMs are revised, manufacturing instructions are updated, suppliers are notified.
Release & Effectivity — The revised parts/assemblies are released with an effectivity date (when does this change take effect?) or serial/lot effectivity (from which unit does this apply?).
Verification — Manufacturing confirms the change was implemented correctly. Quality performs first article inspection on changed parts.
Engineering Change Types
Change Type | Description | Urgency |
|---|---|---|
Safety / Stop-Ship | Defect that could cause injury or regulatory violation | Immediate |
Field Retrofit | Change required for in-service products | High |
Production Stop | Blocks current production | High |
Cost Reduction | Design optimization with no functional impact | Planned |
Obsolescence | Component no longer available; substitute required | Scheduled |
Documentation | Drawing or spec update, no physical change | Low |
ECM in PLM: How Windchill Manages Change
In Windchill, the change management process is codified in a configurable workflow:
Change Request object — Captures problem statement, priority, and affected items
Change Notice — Formal document that consolidates related change requests
Change Order (ECO) — Executable change with full BOM and document impacts
Promotion Requests — Controls when revised parts move from "In Work" to "Under Review" to "Released"
Digital signatures — Records who approved what and when (21 CFR Part 11 compliant)
Effectivity management — Date-based or serial/lot-based effectivity on BOM changes
Downstream notification — Automatic notification to MPMLink (manufacturing) and ERP when changes are released
Common ECM Failures and How to Prevent Them
Failure | Root Cause | Prevention |
|---|---|---|
Unapproved changes reach production | Bypassing ECO process for "minor" changes | Enforce zero tolerance — ALL changes go through ECO |
Long ECO cycle times | Manual routing, email approvals, sequential reviews | Implement PLM-based parallel review workflows |
Incorrect effectivity | Change applies to wrong production lot | Define effectivity rules in PLM; automate ERP update |
No impact assessment | Reviewer doesn't see all affected parts | Use PLM "where used" analysis before every CRB |
Poor documentation | Changes approved verbally without paper trail | All approvals in PLM; no offline approval accepted |
Frequently Asked Questions
What is the difference between an ECR, ECN, and ECO?
These terms are often used interchangeably but have distinct meanings: an ECR (Engineering Change Request) is the initial request identifying a problem. An ECO (Engineering Change Order) is the formal approved change document with implementation instructions. An ECN (Engineering Change Notice) is the notification issued when an ECO is approved and released—it informs affected parties that the change is in effect.
How does engineering change management relate to configuration management?
Configuration management is the broader discipline of ensuring a product is built and maintained to its defined specification. ECM is the change control subprocess within configuration management — it specifically governs how authorized changes to the baseline configuration are made.
What is effectivity in engineering change management?
Effectivity defines when or to which units a change applies. Date effectivity ("effective 2026-04-01") applies to all production after a date. Serial/lot effectivity ("effective from unit 1001") applies to specific product serial numbers or production lots. Correct effectivity management prevents building parts to the wrong revision.
