Engineering Execution System vs PLM
Product Lifecycle Management (PLM) systems are the primary systems for managing product definition in engineering-driven organisations.
They govern product structures, versions, configurations, documents, and change processes.
From a product definition perspective, PLM establishes consistency and traceability.
From an execution perspective, however, PLM addresses a different system layer.
What PLM systems model
PLM systems are designed to answer questions such as:
- What is the current product definition?
- Which version or configuration is valid?
- Which documents and data describe the product?
- How are changes governed and approved?
To do so, PLM focuses on:
- product structures and metadata,
- versioning and configuration logic,
- document control,
- and change management workflows.
This makes PLM indispensable for definition integrity, but insufficient for observing execution reality.
PLM systems describe what the product is.
They do not describe whether the product is executable at a given point in time.
What PLM does not represent
PLM does not model the execution of engineering work itself.
In particular, PLM does not make explicit:
- how engineering work progresses across assemblies and components,
- how unresolved dependencies affect executability,
- how readiness evolves before manufacturing can start,
- or how workload concentration shapes execution risk.
PLM assumes that execution follows definition, but does not observe how execution actually unfolds under evolving definition.
Engineering Execution as a distinct system layer
Engineering Execution refers to the execution of engineering work that transforms definition into executability.
This execution layer:
- exists between definition and production,
- evolves under incomplete and changing product definition,
- and determines whether manufacturing readiness is structurally achieved.
It cannot be derived from product definition data alone.
PLM defines the product.
Engineering Execution determines whether the defined product can actually be realised.
Relation to Product Flow
Product Flow is an Engineering Execution System (EES) that makes this execution layer explicit.
From the perspective of Product Flow:
- PLM remains responsible for definition, versioning, and change governance,
- while engineering execution is analysed as a separate system domain.
Product Flow does not replace PLM.
It complements PLM by exposing readiness, dependency resolution, and execution risk that are invisible at the definition level.
Why the distinction matters
When execution is inferred from definition status:
- readiness is assumed rather than observed,
- unresolved dependencies remain hidden,
- and execution risk emerges late.
Separating Engineering Execution from PLM logic allows execution conditions to be discussed before definition is considered complete or stable.
This comparison reflects the analytical perspective underlying Product Flow.
It does not evaluate PLM tools, vendors, or implementation practices.