BOM change management in PLM: Revisions and traceability in project-based development

A BOM is dynamic. Suppliers change components, designs improve, requirements become stricter and projects evolve along the way. The question is therefore not whether the BOM changes – but how those changes are managed.

Good BOM change management in PLM enables rapid changes without losing control. You know what is changing, why it is changing, who approved it – and which projects, deliveries or installations are affected.

In addition, processes are digitalised and automated, so changes follow a structured workflow with the approvals the business requires.

Revisions – the foundation of traceability

In project-based industries, revision control is essential.

A revision represents an approved technical definition of a component, drawing or structure.

For example, this means that:

• Revision B is an updated technical definition
• The change has been approved through a formal process
• Previous revisions remain traceable

This is crucial when you need to answer questions such as:

• Which version of the design was delivered to the project?
• Which revision was used during production?
• Which documents applied at delivery or installation?

Revision control makes it possible to trace this unambiguously.

When changes are managed without structure

In many organisations, changes in practice begin in CAD or in discussions between engineers.

Without a PLM-supported framework, situations such as these quickly arise:

• CAD is updated, but the BOM and documentation do not automatically follow
• Purchasing orders against older structures
• Production builds from outdated drawings
• Service and aftermarket teams lack accurate spare parts information
• Quality teams receive non-conformances without a clear reference to the applicable design

The consequences often include:

• Duplicated work
• Manual clarification
• Rework or re-engineering
• Delays in project deliveries

PLM addresses this by making changes a controlled process, rather than an informal activity.

A pragmatic BOM change workflow

A practical change management model typically consists of three main steps.

1) Change request (ECR – Engineering Change Request)

A change usually starts with a request.

This describes:

• The problem or improvement
• The root cause or driver (cost, quality, availability, requirements)
• Which products or projects may be affected

This ensures that changes are assessed before they are implemented.

2) Impact analysis

When assessing a change, it is important to understand what it affects.

In PLM, you can quickly identify:

• Which products and structures use the component
• Which documents and drawings need updating
• Whether the component is in stock or on active purchase orders
• Whether testing, validation or certification is required

This overview is difficult to achieve if data is scattered across multiple systems.

3) Change order (ECO / ECN – Engineering Change Order / Notice)

Once the change is approved, it is formally implemented.

This typically involves:

• Updating parts, structures and documentation
• Creating a new revision
• Approval from relevant roles (engineering, quality, production, purchasing)

PLM ensures that every step is documented and traceable.

Project deliveries and baselines

In project-based businesses, it is often important to freeze a technical definition at a given point in time.
This is done by establishing a baseline.

A baseline represents:

• A defined revision of the BOM
• Associated drawings and documentation
• The technical definition applicable to a delivery or project

When the project is subsequently updated or improved, you can still trace which configuration was actually delivered.

This is particularly important for:

• The installed base
• Service and spare parts
• Documentation for customers or authorities

‍

Variant management without copied structures

Many businesses manage variants by copying BOM structures. Over time, this creates a significant maintenance problem.
When a single component changes, all copied structures must be assessed and updated manually.

PLM therefore often uses other principles:

• A 150% BOM containing all possible components
• Configuration rules or options
• Project-specific structures or baselines

This allows changes to be managed centrally while keeping project deliveries traceable.

Summary

BOM change management in PLM is not just about updating a list of parts.

It is about:

• Revision control
• A structured change process
• Impact analysis
• Project baselines
• Traceability throughout the lifecycle

When this works, the business can make necessary changes faster – while retaining control over what has actually been designed, manufactured and delivered.