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Already five posts since we started looking at the roots of PLM, where every step illustrated that new technical capabilities could create opportunities for better practices. Alternatively, sometimes, these capabilities introduced complexity while maintaining old practices.  Where the previous posts were design and engineering-centric, now I want to make the step moving to manufacturing-preparation and the MBOM. In my opinion, if you start to manage your manufacturing BOM in the context of your product design, you are in the scope of PLM.

For the moment, I will put two other related domains aside, i.e., Configuration Management and Configured Products. Note these domains are entirely different from each other.

Some data model principles

In part five, I introduced the need to have a split between a logical product definition and a technical EBOM definition. The logical product definition is more the system or modular structure to be used when configuring solutions for a customer. The technical EBOM definition is, most of the time, a stable engineering specification independent of how and where the product is manufactured. The manufacturing BOM (the MBOM) should represent how the product will be manufactured, which can vary per location and vary over time. Let us look in some of the essential elements of this data model

The Product

The logical definition of the product, which can also be a single component if you are a lower tier-supplier, has an understandable number, like 6030-10B. A customer needs to be able to order this product or part without a typo mistake. The product has features or characteristics that are used to sell the product. Usually, products do not have a revision, as it is a logical definition of a set of capabilities. Most of the time, marketing is responsible for product definition. This would be the sales catalog, which can be connected in a digital PLM environment. Like the PDM-ERP relation, there is a similar discussion related to where the catalog resides—more on the product side later in time.


Related to the product or component in the logical definition, there is an actual EBOM, which represents the technical specification of the product. The image above shows the relation represented by the blue “current” link.

Note: not all systems will support such a data model, and often the marketing sides in managed disconnected from the engineering side. Either in Excel or in a specialized Product Line Engineering (PLE) tools.

We discussed in the previous post that if you want to minimize maintenance, meaning fewer revisions on your EBOM, you should not embed manufacturer-specific parts in your EBOM.

The EBOM typically contains purchase parts and make parts. The purchased parts are sourced based on their specification, and you might have a single source in the beginning. The make parts are entirely under your engineering control, and you define where they are produced and by whom. For the rest, the EBOM might have functional groupings of modules and subassemblies that are defined for reuse by engineering.

Note: An EBOM is the place where multidisciplinary collaboration comes together. This post mainly deals with the mechanical part (as we are looking at the past)

Note: An EBOM can contain multiple valid configurations which you can filter based on a customer or market-specific demand. In this case, we talk about a Configured EBOM or a 150 % EBOM.


The MBOM represents the way the unique product is going to be manufactured. This means the MBOM-structure will represent the manufacturing steps. For each EBOM-purchase-part, the approved manufacturer for that plant needs to be selected. For each make-part in the EBOM, if made in this plant per customer order, the EBOM parts need to be resolved by one or more manufacturing steps combined with purchased materials.

Let us look at some examples:

The flat MBOM

Some companies do not have real machinery anymore in their plants, the product they deliver to the market is only assembled at the best financial location. This means that all MBOM-parts should arrive at the shop floor to be assembled there.  As an example, we have plant A below.

Of course, this is a simplified version to illustrate the basics of the MBOM. The flat MBOM only makes sense if the product is straightforward to assemble. Based on the engineering specifications, the assembly drawing(s) people on the shop floor will know what to do.

The engineering definition specifies that the chassis needs to be painted, and fitting the axles requires grease. These quantities are not visible in the EBOM; they will appear in the MBOM. The quantities and the unit of measure are, of course, relevant here.

Note: The exact quantities for paint and grease might be adjusted in the MBOM when a series of Squads have been manufactured.

The MBOM and Bill of Process

Most of the time, a product is manufactured in several process steps. For that reason, the MBOM is closely related to the Bill of Process or the Routing definitions. The image below illustrates the relationship between an MBOM and the operations in a plant.

If we continue with our example of the Squad, let us now assume that the wheels and the axle are joined together in a work cell. In addition, the chassis is painted in a separate cell. The MBOM would look like the image below:

In the image, we see that the same Engineering definition now results in a different MBOM. A company can change the MBOM when optimizing the production, without affecting the engineering definition. In this MBOM, the Axle assembly might also be used in other squads manufactured by the company.

The MBOM and purchased parts

In the previous example, all components for the Squad were manufactured by the same company with the option to produce in Plant A or in Plant B.  Now imagine the company also has a plant C in a location where they cannot produce the wheels and axle assembly. Therefore plant C has to “purchase” the Wheel-Axle assembly, and lucky for them plant B is selling the Wheel+Axle assembly to the market as a product.

The MBOM for plant C would look like the image below:

For Plant C, they will order the right amount of the Wheel+Axle product, according to its specifications (HF-D240). How the Wheel+Axle product is manufactured is invisible for Plant C, the only point to check is if the Wheel+Axle product complies with the Engineering Definition and if its purchase price is within the target price range.

Why this simple EBOM-MBOM story?

For those always that have been active in the engineering domain, a better understanding of the information flow downstream to manufacturing is crucial. Historically this flow of information has been linear – and in many companies, it is still the fact. The main reason for that lies in the fact that engineering had their own system (PDM or PLM), and manufacturing has their own system (ERP).

Engineers did their best to provide the best engineering specification and release the data to ERP. In the early days, as discussed in Part 4, the engineering specification was most of the time based on a kind of hybrid BOM containing engineering and manufacturing parts already defined.

Next, manufacturing engineering uses the engineering specifications to define the manufacturing BOM in the ERP system. Based on the drawings and parts list, they create a preferred manufacturing process (MBOM and BOP) – most of the time, a manual process.  Despite the effort done by engineering, there might be a need to change the product. A different shape or dimension make manufacturing more efficient or done with existing tooling. This means an iteration, which causes delays and higher engineering costs.

The first optimization invented was the PDM-ERP interface to reduce the manual work and introduction of typos/misunderstanding of data.  This topic was “hot” between 2000 and 2010, and I visited many SmarTeam customers and implementers to learn and later explain that this is a mission impossible. The picture below says it all.

We have an engineering BOM (with related drawings). Through an interface, this EBOM will be restructured into a manufacturing BOM, thanks to all kinds of “clever” programming based on particular attributes.  Discussed in Part 3

The result, however, was that the interface was never covering all situations and became the most expensive part of the implementation.

Good business for the implementing companies, bad for the perception of PDM/PLM.

The lesson learned from all these situations: If you have a PLM-system that can support both the EBOM and MBOM in the same environment, you do not need this complex interface anymore. You can still use some automation to move from an EBOM to an MBOM.

However, three essential benefits come from this approach

  1. Working in a single environment allows manufacturing engineers to work directly in the context of the EBOM, proposing changes to engineering in the same environment and perform manual restructuring on the MBOM as programming logic does not exist. Still, compare tools will ensure all EBOM-parts are resolved in the manufacturing definition.
  2. All product Intellectual Property is now managed in a single environment. There is no scattered product information residing in local ERP-systems. When companies moved towards multiple plants for manufacturing, there was the need for a centralized generic MBOM to be resolved for the local plant (local suppliers / local plant conditions). Having the generic MBOM and Bill of Process in PLM was the solution.
  3. When engineers and manufacturing engineers work in the same environment, manufacturing engineering can start earlier with the manufacturing process definition, providing early feedback to engineering even when the engineering specification has not been released. This approach allows real concurrent engineering, reducing time to market and cost significantly


Again 1600 words this time. We are now at the stage that connecting the EBOM and the MBOM in PLM has become a best practice in most standard PLM-systems. If implemented correctly, the interface to ERP is no longer on the critical path – the technology never has been the limitation – it is all about methodology.

Next time a little bit more on advanced EBOM/MBOM interactions




In this post in the series Learning from the past to understand the future, I want to leave the 3D CAD structures behind. But before doing so, I want to mention some of the lessons learned:

In Part 1:  “Intelligent” drawing numbers were the source for “intelligent” part numbers as often there was a one-to-one relationship between the drawing and the part(s) on a drawing.

In Part 2: 3D CAD has been introduced in the automotive and aerospace industry due to process optimization, where a 3D CAD environment created better collaboration possibilities (DMU). The introduction of 3D CAD in the mid-market was different. Here 3D CAD is used as an engineering tool, not changing any processes.

The complexity grew because also file names needed to be managed, introducing the need for PDM-systems.

In Part 3: we discussed the challenges of working with file-based 3D CAD structures. The versioning problem with check-in/check-out of structure in particular in the case of data reuse. Here the best practice was introduced to have physical parts with a different lifecycle than 3D CAD parts and assemblies.

Now engineers need to create valid configurations based on links between the physical part and the 3D/2D object. This requires a PDM-system with BOM and CAD-files as standard information objects.

In Part 4: we discussed the relations between the BOM and 3D CAD structures without neglecting the fact the 2D Drawing is still the primary legal information carrier for manufacturing/suppliers. The point discussed in this post was the fact that most companies used a kind of ETO-approach. Starting from the 3D CAD-system, adding sometimes manufacturing parts in this structure, to generate a BOM that can be served as input for the ERP-system.

I want to follow up from the last conclusion:

Changing from ETO to CTO requires modularity and a BOM-driven approach. Starting from a 3D CAD-structure can still be done for the lowest levels – the modules, the options. In a configure to order process, it might not be relevant anymore to create a full 3D-representation of the product.

Starting from a conceptual structure

Most companies that deliver products to the market do not start from scratch, as we discussed. They will start from either copying an existing product definition (not recommend) or trying to manage the differences between them, meanwhile keeping shared components under revision control.

This cannot be done based on 3D CAD-structures anymore. At that time (we are in the early 2000s) in the mid-market, the PDM-system was used to manage these structures, in particular, they used the BOM-capabilities.

The BOM-structure was often called the EBOM, as engineers were defining the EBOM. But is it really an EBOM? Let us have a look wat defines an EBOM.

What characterizes an EBOM?

There are many personal definitions of what is considered as an EBOM.  Also, the Wiki-definition here does not help us a lot. So here is my personal 2004 definition:

  • The EBOM reflects the engineering view of a product and, therefore, can have a logical structure of assemblies and subassemblies based on functionality, modularity, and standardization.
  • The EBOM is a part structure specifying a product from its design intent, specifying parts, materials, tolerances, finishing.
  • The EBOM-structure is allowing multidisciplinary teams to work together on a joint definition of the product

The picture below illustrates the above definition.

In this EBOM-structure, we see that the first two levels actually are more a logical division of functional groups, either as units, product/discipline-specific definitions (cabling/software). These components should not be in the EBOM if you have support for logical structures in your PLM-environment. However, in 2004 – PLM was not that mature in the mid-market, and this approach was often chosen.

If we look at the Line Feed module, which could also be used in other products, there is the typical mechanical definition and in parallel the electrical definition. Having them inside a single EBOM gives the advantage of being able to do a “where-used” and status/impact-analysis.

1 – Purchased parts

Motor P280 is an interesting EBOM-part to consider. This motor is required; however, in an EBOM, you should not specify the supplier part number directly. As supplier part availability and preference will change over time, you do not want to revise the EBOM every time a supplier part gets changed.

Therefore, the Motor P280 should have an internal part number in the EBOM. Next, it will be engineering that specifies which motors fulfill the need for Motor P280.   Preferably they will create an Approved Manufacturing List for this motor to give manufacturing/purchasing the flexibility to decide per order where to purchase the motor and from which supplier.

The relation between the Approved Manufacturing List and the Approved Vendor List is shown in the diagram above.

Or follow the link to this image to read more in Arena’s glossary. In particular, for electronic components, this concept is needed as high-level specifications for electronic parts might be the same.

However, the details (tolerances/environment) can be decisive, which component is allowed. Besides, due to the relatively short lifecycle of electronic components, the EBOM needs to be designed in such a manner to anticipate changes in suppliers.

You can only benefit from this approach if, from the beginning of your designs, there are no supplier-specific parts in your EBOM. For Engineering, to Order companies that want to become more Build to Order, this is a challenging but critical point to consider.

Note: The functional characteristics for the motor will come from the electrical definition, and through a reference designator, we create the link between the functional definition and the physical implementation in the product.

2 – Make Parts

Secondly, if we look to the conveyor block D1020 rev A, this block is a make part, with probable a whole assembly of parts below it. As it is a make part, there is at least an assembly drawing and, more likely, a related technical data package linked to D1020 rev A. Make parts still carry a revision as here the Form-Fit-Function discussion can be used when implementing a change of the part.

Note: I used for the final assembly drawing the same number scheme as this is how most companies work. However, in my previous post, I described that if you have a PDM-system in place, the numbering can be different. Maintaining the relations between a part and the related drawing is, in this case, crucial.

The Configured EBOM

The image on the left, we used to illustrate the typical mid-market EBOM in a PDM-system, will become more complicated if we also add options and variants to the EBOM. I assume you know the difference between a variant and an option.

In this case, the EBOM the definition for the full product range. Actually, the top part of the EBOM does not exist as an instance. It is the placeholder to select a resolved EBOM for a specific product configuration.  For the ease of use, I have simplified the initial diagram, now zooming in on variants and options, apologizing for my artistic capabilities as the purpose of a blog is different from a book.

If we look at the diagram, this configured structure contains variants and options.

First, on the logical definition, we see a new grouping. There are two types of Line Feed available, one specific for the X-123 and a later, more generic designed LF100, suitable for all X-1nn variants.

As the LF100 is more generic designed, the customer can select between two motors, the standard P280 and the more advanced version P360, with better service capabilities.

For the Line Feed LF200, there is an option to order a Noise Reduction Cover. It was sold once to an existing customer, and as the cover fits all X-123, it has been linked here as an option to the X-123 definition. So, the customer solution with the Noise Reduction Cover does not have an isolated, copied structure in the EBOM.

Also, in the Logical Structure, we see there is a cabling definition for the X-123 or the default cabling set for all other products.

The diagram illustrates what many mid-market companies have been doing more or less in their PDM-system to avoid copying of EBOM structures per customer order.
It is an example of where a tool (the PDM-system) is slowly abused for administrative reasons. Let me explain why.

The link between Products and (E)BOMs

If we look at the upper part of the configured EBOM structure, this is a logical product definition. Or to say it in different words, it is a portfolio definition, which products and modules a company can sell to the market. Some of the grouping of the portfolio is purely based on business reasons, which products and options do we want to sell.

In most companies, the product portfolio is managed in (marketing) documents without a direct connection to the engineering world. However, we will see in an upcoming post, this relation is crucial for a digital enterprise. Meanwhile, look at on old blog post: Products, BOMs and Parts if you want to be faster

The Engineering definition below the red dashed line is a real EBOM, representing the engineering definition of a system, a module, or a component. When these systems and modules are defined in a single structure that can be filtered based on selection criteria, we talk about a Configured EBOM or sometimes a 150 % EBOM.

Each of the components in the configured EBOM can have a related 3D CAD structure or specification that can be developed traditionally.

The result of a resolved EBOM is a variant that can be delivered to the customer. In this EBOM-driven approach, there is not always a full 3D-representation of the customer product.

Again, size (1500+) words make me stop this story, where next time we will go from product to EBOM and introduce the need for an MBOM in specific industries.


A pure EBOM only specifies a product and contains all relevant information in context – designs & specifications. The EBOM should not be mixed or confused with a logical grouping, belonging to a portfolio definition (even if the system allows you to do it)

On my previous post shared on LinkedIn Ilan Madjar, a long-time PLM colleague reacted with the following point (full thread here)

Ilan is pointing to the right challenge in many companies. Changing the way you work is though exercise and requires a good understanding, vision, and execution to move forward. Do not trust the tool to work for you – it is about human understanding and process re-engineering to be more efficient. And if you do not practice this on the basic PDM-level as discussed so far, imagine the impossibility of going through a digital transformation.


Last time in the series Learning from the past to understand the future, we zoomed in on how the 3D CAD-structure in the mid-market had to evolve. In a typical Engineering To Order (ETO) scenario, it makes sense to extract from the 3D CAD-structure a BOM-structure to collect all the individual parts that are needed for manufacturing. Combined with the drawings generated based on the 3D CAD assemblies/parts, the complete manufacturing information could be provided. Let’s have a look.

The BOM in ERP (part 1)

To understand what most mid-market companies have been doing, I created the image below. When you click on it, you will have an enlarged version.

Note: for educational purposes an extremely simplified example

There is a lot to explain here.

First, on the right we see the 3D CAD assembly, two phantom assemblies, grouping the wheels and the axle. And at the end, the individual parts, i.e. chassis, axle, and wheel. The 3D CAD-structure is an instance-based structure; therefore, there are no quantities in the structure (all quantity 1)

For the individual parts, there are drawings. Also, for the product, we have an assembly drawing. The drawings are essential as we want to have them in the ERP-system for manufacturing.

Finally, the physical parts, now with a different ID than the drawing as we learned this one-to-one relation created a lot of extra work. The physical parts are often called Items or Materials (SAP naming). Unfortunately, for engineering, there is a different meaning behind Materials. Still, SAP’s data model was not built with an engineering mindset.

The physical part structure, which we call the BOM contains quantities. Most PDM-CAD-integrations can filter out phantom assemblies and summarize the parts on the same level

I am still reluctant to call the Part-structure an EBOM as the design of the product has been mainly focusing on extracting manufacturing information, parts, and drawings.

The BOM in ERP (part 2)

In customized PDM-implementations, some implementers created an interface from the BOM-structure to ERP, so the ERP-system would have the basic definition of the parts and a copy of the relevant drawings.

Now manufacturing could create the manufacturing definition without the need to go into the PDM-system.

Some “clever” – Dick Bourke would say “smart – therefore lazy” – proposed to “draw” also manufacturing entities in the 3D CAD-structure, so the PDM-CAD-interface would automatically deliver manufacturing parts too inside the ERP. In the example below, we added paint for the body and grease needed for the axels.

Although “smart, a new problem was introduced here – the 3D CAD-structure, instance-based, always has quantities 1. The extracted BOM would have rounded numbers when considering design parts. Now the grease comes with an estimate of  0.025 kg, assuming quantities are based on SI-units. We could also add other manufacturing information to this BOM, like 0.3-liter paint. Anyway, the result would look like below:

Important to notice from the diagram here: There are placeholders for grease and paint “drawn” in the 3D CAD-structure – parts without a geometrical definition and, therefore, not having an associated drawing. However, these parts have a material specification, and therefore in the BOM-structure, they appear as Materials.

Next in the BOM-structure, the engineers would enter the expected/required quantity – which is no longer a rounded number.

At this stage, you cannot call the BOM on the left an EBOM. It is a kind of hybrid structure, combining engineering and manufacturing data. A type of BOM we discover a lot in companies that started with a type of ETO-product.

The ETO-product

Many companies that developed specialized machinery have started with a base product, from where they developed the custom solution – their IP. Next, with more and more customers, the original solution was extended by creating either new or changed capabilities.

I worked a lot with companies that moved to the full definition of their products in 3D CAD, creating a correct 3D CAD-structure per customer order. Instead of creating new BOM variants, companies were often tempted/forced to make the configuration inside the 3D CAD-model.

The 3D CAD vendor often provided functionality to have multiple configurations of the same part/product inside a single file. A nice feature for designers as there are fewer files to maintain, however, a crime for data management.

Every time one of the configurations of the part would change, or a new configuration was added, the file has to be revised.

And if the change was at level five of a 3D CAD-structure, many assembly files needed to be updated. The versioning problem illustrates the challenge of managing configurations inside a 3D CAD-file, meanwhile creating complexity for the PDM/PLM-system.

Last week Tech-Clarity published the highlights of their survey: Bringing Custom-Engineered Products to Market with a link to the full report, sponsored by Propel.

As you can imagine, this survey is more about PLM collaboration, breaking down the silos and acting agile. Unfortunately, the report does not expose required methodologies, like modularity and “common sense” engineering practices that we discuss here. Still worthwhile to read as the report addresses precisely the type of companies I am referring too here.

If we look at the methodology of custom-engineered products, let us look at how their “best practice” from the past is blocking the future.

When a new customer request is coming in, sales engineering is looking for the best match of delivered products. Hopefully, 80-90 % remains the same, and engineering has to focus only on the differences.

First, the best-match 3D CAD-structure is copied to a new project. As you can see most 3D CAD-systems provide the functionality to create a derived structure from an original 3D CAD-structure. From there, a traditional ETO-process starts as described at the beginning of this post. We complete the 3D CAD-structure with manufacturing in mind, generate the BOM and drawings, and we can deliver. In the case of purchase parts, the generated BOM often contains already the supplier part number in the 3D CAD-structure as we are focusing on this single delivery.

The disadvantage of this approach that in theory, we have to check if the structure that we reused is really the best so far, otherwise we introduce errors again.

The second disadvantage is that if one supplier part in the structure becomes obsolete and needs to be revised, the company has to go through all the 3D CAD-structures to fix it.

Also, having supplier parts in the 3D CAD-structure makes it more difficult to standardize, as the chosen supplier part matched the criteria for that customer at that time. Will it match the criteria also in other situations?

From ETO to BTO to CTO

Many companies that started with custom-engineered products, the ETO-approach, want to move towards a Configure To Order (CTO) approach – or if not possible at least Build To Order (BTO). More reuse, less risk,  instead of creating every time a new solution for the next customer, as discussed before.

This is not a mission impossible; however, often, I have seen that companies do not set the right priorities to move towards a configure to order environment. There are a few changes needed to become a configure to order company (if possible):

  1. Analyze your solution and define modules and options. Instead of defining a full solution, the target now is to discover a commonality between the various solutions. Based on commonality, define modules and options in such a manner that they can be used in different situations. Crucial for these modules is that there is a standard interface to the rest of the product. Every company needs to master this specific methodology for their products
  2. Start defining products from a logical structure, defining how products, modules and options are compatible and which combinations are allowed (or preferred). For companies that are not familiar with logical structure, often a configured EBOM is used to define the solutions. Not the optimal way; however, this was the first approach most companies took ten years ago. I will explain the configured EBOM below.
  3. A product definition and its modules now should start from a real EBOM, not containing manufacturing characteristics. The EBOM should represent the logical manner of how a product is defined. You will notice this type of EBOM might be only 2 – 3 levels deep. At the lowest level, you have the modules that have their own lifecycle and isolated definition.
  4. You should no longer use supplier part numbers in your EBOMs. As the engineering definition of a module or option should not depend over time from a single supplier. We will discuss in the next post the relation between EBOM parts and the Approved Manufacturer List (AML)

To conclude for today

Changing from ETO to CTO requires modularity and a BOM-driven approach. Starting from a 3D CAD-structure can still be done for the lowest levels – the modules, the options. In a configure to order process, it might not be relevant anymore to create a full 3D-representation of the product.

However, when we look forward, it would be greatly beneficial to have the 3D-representation of every specific solution delivered. This is where concepts as augmented/virtual reality and digital twin come in.

Next time more on the BOM-structures – as we have just touched the upcoming of the EBOM – enough to clarify next week(s).

In my last post related to Learning from the past to understand the future, I discussed what happened when 3D CAD became available for the mid-market. In the large automotive or aerospace & defense companies, 3D CAD has been introduced along the path of defining processes and selecting tools. In the mid-market 3D CAD started from the other side, first as a productivity tool, not thinking further to change methodologies or processes.

The approach starting with 3D CAD without changing processes, has created several complexities. Every company that is aiming to move towards a digital future needs to reduce complexity to remain competitive. Now let us focus on the relation between the 3D CAD-structure and a BOM.

The 3D CAD-structure

When building a product in a 3D CAD system, the concept is that you have individual parts designed in 3D.  Every single part has a unique identifier.

If possible, the (file) name would equal the physical part number.

Next, a group of parts could be stored as a subassembly. Such an assembly is sometimes called a phantom assembly, in case they only group together several 3D parts. The usage of this type of assemblies increased CAD productivity. For data management reasons, these assemblies need to have a unique identifier, preferably not with the same numbering scheme for physical part numbers. It would consume part numbers that would never be used during manufacturing.

Note: in the early days of connecting 3D CAD to ERP, there was a considerable debate about which system could generate the part number.

ERP has always been the leading system for parts definition, why change ? And why generate part numbers that might not be used later in production. “Wasting” part numbers was a bad practice as historically, the part number was like a catalog number: 6 to 7 digits.

Next, there is also another group of subassemblies that represent one or more primary components of a product. For example, a pump assembly, that might be the combination of the pump, the motor, and the base frame. This type of assembly appears most of the time high in the CAD-structure. They can be considered as a phantom assembly too, regarding a required identifier for this subassembly.

Finally, there might be parts in the CAD-structure that will not exist in reality as part but need to be created during the manufacturing process. Sheet metal parts are created during the manufacturing process. Cappings, strips and cables shown in the CAD-structure might come from materials that are purchased in standardized sizes (1 meter / 2 meter / 10 meter) and need to be cut during manufacturing. Here the instances in the CAD-structure will have a unique identifier. What type of identifier to use depends on the manufacturing process. It might be a physical part number, as it is a half-fabricate,  or it remains a unique identifier for the CAD-structure only.

The reason I am coming back to these identifiers is that as described before, companies wanted to keep a relation between the part number and the file name.

There was a problem with flexible parts. A rubber hose with a specific length could be shaped differently in an assembly based on its connection. Two different shapes would create two files and therefore break the rule of a part number equals file name. The 3D CAD vendors “solved” this issue by storing configurable views of the same part inside one file and allow the user to select the active view.

Later we will see that management of views inside the 3D CAD model is not a wrong choice. This, contrary to managing different configurations of a part/product inside a single file, which creates complexity in the PLM domain.

In the end, the product became an assembly with several levels of subassemblies. At that time, when I worked a lot with CAD-integrations, the average depth of 3D CAD-structures was 6 to 7 levels deep, with exceptions in both directions.

The entire product CAD-structure is mainly used for a final digital mock-up, to allow engineers to analyze the full product behavior.  One of my favorite YouTube movies is the one from Airbus – seven years ago, they described the power of a full digital mock-up used for the A380.

In ETO-processes, the 3D CAD-structure is unique for a given customer solution – like the A380.

In the case of large assemblies with a lot of parts and subassemblies,  there were situations where the full product could not be resolved anymore. For Airbus a must, for the mid-market not always easy to reach.  Graphics memory, combined with the way graphics were represented, are the major constraint. This performance issue is resolved in the gaming world, however then the 3D representation had no longer the required accuracy or definition.

The Version pop-up problem

Working with a 3D CAD structure created a new problem when designers were sharing parts and assemblies between themselves and suppliers. The central storage of the files required a versioning mechanism, supported by a check-in and check-out mechanism.

Depending on the type of 3D CAD integration, the PDM system generated a new minor revision of the file after check-in again. In this way, there was full traceability of the changes before release. The image below shows an example of how SmarTeam was dealing with minor and major revisions combined with lifecycle stages.

When revising a part, all assemblies that contained the changed part need to be updated too, in case you want to have traceability and preventing others from overwriting your version. Making sure this assembly file points to the right file again. In the cases of a 6-level deep CAD-structure, this has led to a lot of methodology problems on how to deal (or not to deal) with file changes.

In the case of a unique delivery for a customer, the ETO-process, the issue might not be so big. As everything in the 3D CAD-structure is work in progress, you only need to be sure during the release process of the 3D CAD-structure that all parts and assemblies are resolved to the latest version (and verified)

Making changes on an existing product is way more complicated, as assemblies are released, and parts exist in production.  In that case, the Bill of Material is the leading structure to control the versions and the change impact, as we will see.

Note: Most CAD- and PLM-vendors loved to show you their demos, where starting from the CAD-structure, a product gets created (the ETO-process). The reality is that most companies do not start from the CAD-structure, but from an existing Bill of Material. In 2010, I wrote a few posts, discussing the relation between CAD and the BOM:

to explain there is more than a CAD-driven scenario.


In most PDM-systems with CAD-integrations, it is possible to create a Bill of Materials from the 3D CAD-structure. The Bill of Materials will be based on the parts inside the 3D CAD-structure. There is often the option to filter out phantom assemblies.

The structures are not the same. The 3D CAD-structure is instance-based, where the extracted Bill of Materials will summarize the part quantities on the same level.  See the image below. There are four Wheel instances in the CAD structure, in the EBOM-structure, we have only one Wheel reference with quantity 4.

I named the structure on the right the EBOM as the structure represents the Bill of Materials from the engineering point of view. This definition is a little arbitrary, as we will see. In companies that started to develop products based on a conceptual BOM, often, this conceptual BOM was an “early” EBOM that had to be developed further. This EBOM was more representing a logical or modular structure driving the design, instead of an extract from the 3D CAD-structure. In the next post, I will zoom in on these differences. I want to conclude this time with a critical methodology needed to manage the 3D CAD structure changes in relation to an EBOM.

Breaking the rule Drawing ID (Model ID)  = Part ID

Although I have been writing mostly about the 3D CAD structure, I want to remind us that the 3D Model in the mid-market is mainly used for design purposes. The primary delivery for manufacturing or a supplier is still a 2D-drawing for most companies. The 3D Model might be “nice to have” for CAM- or quality usage. Still, in case of a dispute, the 2D Drawing will be leading.

For that reason, in many mid-market companies, there was the following relation below:

In an environment without file versioning through check-in/check-out, this relation was easy to maintain. In the electronic world, every change in the 3D Model (which could be an assembly) triggers a new file version and, therefore, most of the time, a new version of the drawing and the physical part. However, you do not want to have a physical part with many revisions, in particular when this part could be again part of a Bill of Material.

To solve this issue, the Physical Part and the related Drawing/Model should have different lifecycles. The relation between the Physical Part and the Drawing Model should no longer be based on numbers but on a relation in the PDM/PLM-system. One of the main characteristics of a PDM/PLM-system is that it allows users to navigate through relations to find information in context.  For example, solving a Where Used – question is a (few) mouse-click(s) in a PDM/PLM-system.

Click on the image to see the details.

Breaking this one-to-one numbering rule is a must if you want to evolve to an item-centric or data-driven PLM-environment. When to introduce this change and how to implement this new behavior is a methodology exercise, not an implementation of a new tool.

There is a lot to read about this topic as it is related to the Form-Fit-Function-discussion we had earlier this year. A collection of information can be found in these two LinkedIn-post, where the comments are providing the insights:


I will not dive deeper into this theme (reached 1700 words ☹) – next time I will zoom in on the EBOM and leave the world of 3D CAD behind (for a while)



Two weeks ago, I wrote about the PLM Innovation Forum, a virtual conference organized by TECHNIA, where I described some of my experiences with the event and the different ways of interaction in a virtual conference.

The content remains available till May 31st, so I had time to stroll through the rich content offered. In particular, if you are already familiar with the Dassault Systèmes & TECHNIA offerings, the content is extremely rich.

From the “auditorium“, I selected four presentations that have a logical relation to each other. I believe they will help you understand some of the aspects of PLM independent of the PLM vendor. Let’s start.

Value-Driven Implementation

In this session, Johannes Storvik, you can identify three parts. In the first part, Johannes talks about how to select the best PLM-approach, discussing the various options from custom, standardized, or even fully Out-Of-The-Box, comparing these options with building types. An interesting comparison, however, there is a risk with this approach.

Many companies are now stating they only need a collection of Commercial of the Shelf (COTS) systems and prefer only OOTB. The challenge with this approach is that you start from the tools, constraining the business from the start.

I would state start from your business goals, and ultimately they will lead to requirements for the tools. And then, if available, you find solutions that require no or minor adaptation. Starting from the business is crucial, and Johannes elaborates more on that.

The second part discussing PLM benefits, and if you are looking for confirmation PLM brings value, have a look at the topics, areas, and numbers mentioned. Most benefits and areas are quite traditional, related to a coordinated organization (if you follow my coordinated to connected typology).

The last part, connecting the dots from business to enablers, a Benefits Dependency Network, is a methodology that I recommend. Originally developed by Cranfield School of Management, it allows you to connect your PLM-needs to the company’s business needs and strategies. You can read more about this methodology in this HBR article: A tool to map your next digital initiative.

Benefits Dependency Network: note the potential storyline you can build

My experience from this methodology is that it allows you to extract one, two perhaps three storylines. These storylines then help you to explain why the PLM enablers are needed connecting to a business case into one understandable storyline, suitable for all levels in the company

With Johannes, we went from PLM-characteristics towards connecting PLM to the business and exec management, making PLM implicit visible at the management level. Now the next step.

Industrialization of the Construction Industry

The theme of this session might be misleading. Arto Tolonen, from the LETHO group, has a long history in PLM as a practitioner and at the University of Oulu, where he specialized in Product Data Management and Product Portfolio Management.

The last part of his presentation is dealing with transformational thinking for the construction industry from a one-off construction towards thinking in repeatable processes, using PLM practices. With his dry humor, he asks:
“Why are all buildings prototypes ?” and more.

For many years, I have been preaching PLM practices to be valuable for other industries too. See this 2013 post: PLM for all industries?  The most common challenge was to respond to the question:  “What does your tool do?”   PLM practices only become valuable if you think in repeatable processes.

The exciting part is when Arto talks about the disconnect between the exec level in an organization and reality in the field. Understanding how products are performing, and how each product contributes to the profit of the company, is usually blurred with subjective information. Your company’s love baby might be the worst performer but never dropped from the product portfolio for sentimental reasons.

Arto explains the importance of (digital) portfolio management, connecting the economic data with the technical data. And by doing so, use portfolio management to drive the development of new offerings based on market needs and numbers. Or to decommission products.

I am fully aligned with Arto and believe that a digital transformation should include a connected product portfolio management environment, driving new development projects. Product Portfolio management is not the same as BOM-management.

The portfolio items are facing the outside world, your customers. How the products are built, is defined in the inside world of BOMs and design data.

Now combining product portfolio management with product management makes a lot of more sense if you are going to use it to support the modularization of your products. Based on solution platforms, you can design your products to become modular, leading to a lot of business benefits.

With Arto, we discovered the need to have digital portfolio management connecting business performance and product development. Another implicit reason for PLM to your business explained with humor. Now the next step.


Closely related to product portfolio management is the topic of modularization.  If you want to optimize your offering with a great variety of choices for your customers, without spending more time to develop an individual solution, you need to implement modularization for your products.

Daniel Strandhammar van Brick Strategy explains this topic in his session. So many companies I am working with a claim that they want to move from and ETO (Engineering To Order) model to a CTO (Configure To Order) model. Unfortunately, many of them keep on talking about that without making steps towards more configurable products.

Although in many PLM-infrastructures, the capabilities exist to support the modularity of a product portfolio, it requires thinking and analysis outside the tools. The tools are there to support the modularization. Still, it depends on your engineering teams to transform the company’s portfolio step by step into a more modular product.  Brick Strategy is typical such a company that can help you and coach you in a modularization process.

If you look at the benefits Daniel is mentioning related to modularization, these benefits are significant. However, as Daniel also explains per type of business, the effects of modularization might be different, still in every situation worth to invest.

It is interesting to know that many of the modularization methodologies come from Scandinavian countries. Perhaps a region, with companies like Scania (master of modularization), IKEA and others leading the ways towards modularization. Is it a surprise that LEGO is also a Scandinavian company?

Daniel continues by explaining how a roadmap for modularization could look like. If you are struggling with that point, have a look at the video. It is a crucial part of the story.

Note: There is also a presentation from Anders Malmberg fro Scania talking about their Starling project. Not particularly related to modularization, more related to how to organize significant PLM transformations.

With Daniel’s presentation, we see the relation between a product portfolio and modularization. Another implicit reason for PLM to improve your business explained. Now let’s do it.


Making Multi-view BOM a reality

My ultimate dream was that James Roche from CIMdata would complete the storyline. We went from business initiatives through product portfolio management and modularization through a flow of organizational topics to enhance your business outcome using PLM.

With James, I was hoping we now would get the final necessary part, the need for a multi-view BOM, and how to establish this. As I mentioned before with modularization, many companies started with a kind of ETO-approach to deliver solutions for their customers. The downside of this approach is that, when designing a product, the manufacturing process was already leading the way the BOM will be structured. Many of the companies that I work with are in this situation. There is no clear EBOM and MBOM, the situation is a kind of hybrid BOM, blocking modularity and multi-plant manufacturing.

James’s presentation unfortunate started with a 10 min technical delay, and then the next part is crucial to understand. He explains nicely what it means to have a “hybrid” single BOM and more to a multi-view EBOM/MBOM. James addressed this topic, both using an example looking at it from a technological and organizational view.

As James is the CIMdata Practice Director for Aerospace & Defense, this was the industry in focus and even example provided above is not necessarily the best solution for every A&D company. Organizational change and managing risks are crucial in such a transition, and that is where James spent even more time. It would be great, and I consider it one of my next blog options, to discuss and share best practices for other types of industries. Is there always a need for a multi-view BOM and are they all the same?

With James we concluded the PLM value story, making it my fourth pick of the PLMIF conference, giving you an end-to-end storyline why PLM is important and how it is connected to your business results.



The four presentations that I highlighted here show a storyline that is crucial to understand and pitch when you talk about the business value of PLM. It is not about technical features and functions. It is part of a business strategy, building the right portfolio, manage it in a modular manner, and use multiple BOM views to optimize the delivery of your products.


Note: two more weeks to see the full presentations of PLMIF – go and have a look in case you haven’t done so:




The digital thread according to GE

In my earlier posts, I have explored the incompatibility between current PLM practices and future needs for digital PLM.  Digital PLM is one of the terms I am using for future concepts. Actually, in a digital enterprise, system borders become vague, it is more about connected platforms and digital services. Current PLM practices can be considered as Coordinated where the future for PLM is aiming at Connected information. See also Coordinated or Connected.

Moving from current PLM practices towards modern ways of working is a transformation for several reasons.

  • First, because the scope of current PLM implementation is most of the time focusing on engineering. Digital PLM aims to offer product information services along the product lifecycle.
  • Second, because the information in current PLM implementations is mainly stored in documents – drawings still being the leading In advanced PLM implementations BOM-structures, the EBOM and MBOM are information structures, again relying on related specification documents, either CAD- or Office files.

So let’s review the transformation challenges related to moving from current PLM to Digital PLM

Current PLM – document management

The first PLM implementations were most of the time advanced cPDM implementations, targeting sharing CAD models and drawings. Deployments started with the engineering department with the aim to centralize product design information. Integrations with mechanical CAD systems had the major priority including engineering change processes. Multidisciplinary collaboration enabled by introducing the concept of the Engineering Bill of Materials (EBOM).  Every discipline, mechanical, electrical and sometimes (embedded) software teams, linked their information to the EBOM. The product release process was driven by the EBOM. If the EBOM is released, the product is fully specified and can be manufactured.

Although people complain implementing PLM is complex, this type of implementation is relatively simple. The only added mental effort you are demanding from the PLM user is to work in a structured way and have a more controlled (rigid) way of working compared to a directory structure approach. For many people, this controlled way of working is already considered as a limitation of their freedom. However, companies are not profitable because their employees are all artists working in full freedom. They become successful if they can deliver in some efficient way products with consistent quality. In a competitive, global market there is no room anymore for inefficient ways of working as labor costs are adding to the price.

The way people work in this cPDM environment is coordinated, meaning based on business processes the various stakeholders agree to offer complete sets of information (read: documents) to contribute to the full product definition. If all contributions are consistent depends on the time and effort people spent to verify and validate its consistency. Often this is not done thoroughly and errors are only discovered during manufacturing or later in the field. Costly but accepted as it has always been the case.

Next Step PLM – coordinated document management / item-centric

When the awareness exists that data needs to flow through an organization is a consistent manner, the next step of PLM implementations come into the picture. Here I would state we are really talking about PLM as the target is to share product data outside the engineering department.

The first logical extension for PLM is moving information from an EBOM view (engineering) towards a Manufacturing Bill of Materials (MBOM) view. The MBOM is aiming to represent the manufacturing definition of the product and becomes a placeholder to link with the ERP system and suppliers directly. Having an integrated EBOM / MBOM process with your ERP system is already a big step forward as it creates an efficient way of working to connect engineering and manufacturing.

As all the information is now related to the EBOM and MBOM, this approach is often called the item-centric approach. The Item (or Part) is the information carrier linked to its specification documents.


Managing the right version of the information in relation to a specific version of the product is called configuration management. And the better you have your configuration management processes in place, the more efficient and with high confidence you can deliver and support your products.  Configuration Management is again a typical example where we are talking about a coordinated approach to managing products and documents.

Implementing this type of PLM requires already more complex as it needs different disciplines to agree on a collective process across various (enterprise) systems. ERP integrations are technically not complicated, it is the agreement on a leading process that makes it difficult as the holistic view is often failing.

Next, next step PLM – the Digital Thread

Continuing reading might give you the impression that the next step in PLM evolution is the digital thread. And this can be the case depending on your definition of the digital thread. Oleg Shilovitsky recently published an article: Digital Thread – A new catchy phrase to replace PLM? related to his observations from  ConX18 illustrate that there are many viewpoints to this concept. And of course, some vendors promote their perfect fit based on their unique definition. In general, I would classify the idea of Digital Thread in two approaches:

The Digital Thread – coordinated

In the Digital Thread – coordinated approach we are not revolutionizing the way of working in an enterprise. In the coordinated approach, the PLM environment is connected with another overlay, combining data from various disciplines into an environment where the dependencies are traceable. This can be the Aras overlay approach (here explained by Oleg Shilovitsky), the PTC Navigate approach or others, using a new extra layer to connect the various discipline data and create traceability in a more or less non-intrusive way. Similar concepts, but less intrusive can be done through Business Intelligence applications, although they are more read-only than a system approach.

The Digital Thread – connected

In the Digital Thread – connected approach the idea is that information is stored in an extreme granular way and shared among disciplines. Instead of the coordinated way, where every discipline can have their own data sources, here the target is to be data-driven (neutral/standard formats). I described this approach in the various aspects of the model-based enterprise. The challenge of a connected enterprise is the standardized data definition to make it available for all stakeholders.

Working in a connected enterprise is extremely difficult, in particular for people educated in the old-fashioned ways of working. If you have learned to work with shared documents, like Google Docs or Office documents in sharing mode, you will understand the mental change you have to go through. Continuous sharing the information instead of waiting until you feel your part is complete.

In the software domain, companies are used to work this way and to integrate data in a continuous stream. We have to learn to apply these practices also to a complete product lifecycle, where the product consists of hardware and software.

Still, the connect way if working is the vision where digital enterprises should aim for as it dramatically reduces the overhead of information conversion, overhead, and ambiguity. How we will implement in the context of PLM / Product Innovation is a learning process, where we should not be blocked by our echo chamber as Jan Bosch states it in his latest post: Don’t Get Stuck In Your Company’s Echo Chamber

Jan Bosch is coming from the software world, promoting the Software-Centric Systems conference SC2 as a conference to open up your mind. I recommend you to take part in upcoming PLM related events: CIMdata’s PLM roadmap Europe combined with PDT Europe on 24/25th October in Stuttgart, or if you are living in the US there is the upcoming PI PLMx CHICAGO 2018 on Nov 5/6th.


Learning and understanding are crucial and takes time. A digital transformation has many aspects to learn – keep in mind the difference between coordinated (relatively easy) and connected (extraordinarily challenging but promising). Unfortunate there is no populist way to become digital.

If you want to continue learning, please read this post – The True Impact of Industry 4.0 Revealed  -and its internal links to reference information from Martijn Dullaart – so relevant.


Last week I got the following question:

Many companies face the challenges relevant to the cooperation and joint ventures and need to integrate in a smart way the portfolio’s to offer integrated solutions. In the world of sharing and collaboration, this may be a good argument to dig into. Is PLM software ready for this challenge with best practice solutions or this is a matter that is under specific development case by case? Any guidelines?

Some history

When PLM solutions were developed their core focus was on bringing hardware products to the market in a traditional manner as shown in the figure below. clip_image001

Products were pushed to the market based on marketing research and closed innovation. Closed innovation meant companies were dependent on their internal R&D to provide innovative products. And this is the way most PLM systems are implemented: supporting internal development. Thanks to global connectivity, the internal development teams can collaborate together connected to a single PLM backbone/infrastructure.

Third Party Products (TPP) at that time were sometimes embedded in the EBOM, and during the development phase, there would be an exchange of information between the OEM and the TPP provider. Third Party Products were treated in a similar manner as purchase items. And as the manufacturing of the product was often defined in the ERP system, there the contractual and financial interactions with the TTP provider were handled, creating a discontinuity between what has been defined for the product and what has been shipped. The disconnect between the engineering intent and actual delivery to the customer often managed in Excel spreadsheets or proprietary databases developed to soften the pain

What is happening now?

In the past 10 – 15 years there is the growing importance of first electronic components and their embedded software now followed by new go-to-market approaches, where the customer proposition changes from just a product, towards a combined offering of hardware, software, and services. Let´s have a look how this could be done in a PLM environment.

From Products to Solutions

The first step is to manage the customer proposition in a logical manner instead of managing all in a BOM definition. In traditional businesses, most companies still work around multiple Bill of Materials. For example, read this LinkedIn post: The BOM is King. This approach works when your company only delivers hardware.

Not every PLM system supports Out-Of-The-Box a logical structure. I have seen implementations where this logical structure was stored in an external database (not preferred) or as a customized structure in the PLM system. Even in SmarTeam, this methodology was used to support Asset Lifecycle Management. I wrote about this concept early 2014 in the context of Service Lifecycle Management(SLM) two posts: PLM and/or SLM ? and PLM and/or SLM (continued). It is no coincidence that concepts used for connecting SLM to PLM are similar to defining customer propositions.

PropositionIn the figure to the left, you can see the basic structure to manage a customer proposition and how it would connect to the aspects of hardware, software, and services. In an advanced manner, the same structure could be used with configuration rules to define and create a portfolio of propositions. More about this topic potential in a future blog post.

For hardware, most PLM systems have their best practices based on the BOM as discussed before. When combining the hardware with embedded software, we enter the world of systems. The proposition is no longer a product it becomes a system or even an experience.

For managing systems, I see two main additions to the classical PLM approach:

  1. The need for connected systems engineering. As the behavior of the system is much more complicated than just a hardware product, companies discover the need to spend more time on understanding all the requirements for the system and its potential use cases in operation – the only way to define the full experience. Systems Engineering practices coming from Automotive & Aerospace are now coming into the world of high-tech, industrial equipment, and even consumer goods.
  2. The need to connect software deliverables. Software introduces a new challenge for companies, no matter if the software is developed internally or embedded through TTP. In both situations, there is the need to manage change in a fast and iterative manner. Classical ECR /ECO processes do not work here anymore. Working agile and managing a backlog becomes the mode. Application Lifecycle Management connected to PLM becomes a need.

In both domains, systems engineering, and ALM, PLM vendors have their offerings, and on the marketing side, they might all look the same to you. However, there is a fundamental need that is not always visible on the marketing slides, the need for complete openness.


opennessTo manage a portfolio based on systems a company can no longer afford to manually check in multiple management systems all the dependencies between the product and its components combined with the software deliverables and TTPs. Automation, traceability on changes and notifications are needed in a modern, digital environment, which you might call a product innovation platform. My high-speed blog buddy Oleg Shilovitsky just dedicated a post to “The Best PLM for Product Innovation Platform” sharing several quotes from CIMdata´s talk about characteristics of a Product Innovation Platform and stressing the need for openness.

It is true if you can only manage your hardware (mechanics & electronics) and software in dedicated systems, your infrastructure will be limited and rigid as the outside world is in constant and fast changes. No ultimate solution or product does it all and will do it all in the future. Therefore openness is crucial.


In several companies, original in the Engineering, Procurement & Construction industry, I have seen the need to manage services in the context of the customer delivery too. Highly customized systems and/or disconnected systems were used here. I believe the domain of managing a proposition, a combination of hardware, software, AND services in a connected environment is still in its early days. Therefore the question marks in the diagram.


How Third Party Products management are supported by PLM depends very much on the openness of the PLM system. How it connects to ALM and how the PLM system is able to manage a proposition. If your PLM system has been implemented as a supporting infrastructure for Engineering only, you are probably not ready for the modern digital enterprise.

Other thoughts ???

In my series describing the best practices related to a (PLM) data model, I described the general principles, the need for products and parts, the relation between CAD documents and the EBOM, the topic of classification and now the sensitive relation between EBOM and MBOM.

First some statements to set the scene:

  • The EBOM represents the engineering (design) view of a product, structured in a way that it represents the multidisciplinary view of the functional definition of the product. The EBOM combined with its related specification documents, models, drawings, annotations should give a 100 % clear definition of the product.
  • The MBOM represents the manufacturing view of a product, structured in a way that represents the way the product is manufactured. This structure is most of the time not the same as the EBOM, due to the manufacturing process and purchasing of parts.


A (very) simplified picture illustrating the difference between an EBOM and a MBOM. If the Car was a diesel there would be also embedded software in both BOMs (currently hidden)

For many years, the ERP systems have claimed ownership of the MBOM for two reasons

  1. Historically the MBOM was the starting point for production. Where the engineering department often worked with a set of tools, the ERP system was the system where data was connected and used to have a manufacturing plan and real-time execution
  2. To accommodate a more advanced integration with PDM systems, ERP vendors began to offer an EBOM capability also in their system as PDM systems often worked around the EBOM.

These two approaches made it hard to implement “real” PLM where (BOM) data is flowing through an organization instead of stored in a single system.

By claiming ownership of the BOM by ERP, some problems came up:

  • A disconnect between the iterative engineering domain and the execution driven ERP domain. The EBOM is under continuous change (unless you have a simple or the ultimate product) and these changes are all related to upstream information, specifications, requirements, engineering changes and design changes. An ERP system is not intended for handling iterative processes, therefore forcing the user to work in a complex environment or trying to fix the issue through heavy customization on the ERP side.
  • Global manufacturing and outsourced manufacturing introduced a new challenge for ERP-centric implementations. This would require all manufacturing sites also the outsourced manufacturers the same capabilities to transfer an EBOM into a local MBOM. And how do you capitalize the IP from your products when information is handled in a dispersed environment?

The solution to this problem is to extend your PDM implementation towards a “real” PLM implementation providing the support for EBOM, MBOM, and potential plant specific MBOM. All in a single system / user-experience designed to manage change and to allow all users to work in a global collaborative way around the product. MBOM information then will then be pushed when needed to the (local) ERP system, managing the execution.

Note 1: Pushing the MBOM to ERP does not mean a one-time big bang. When manufacturing parts are defined and sourced, there will already be a part definition in the ERP system too, as logistical information must come from ERP. The final push to ERP is, therefore, more a release to ERP combined with execution information (when / related to which order).

In this scenario, the MBOM will be already in ERP containing engineering data complemented with manufacturing data. Therefore from the PLM side we talk more about sharing BOM information instead of owning. Certain disciplines have the responsibility for particular properties of the BOM, but no single ownership.

Note 2: The whole concept of EBOM and MBOM makes only sense if you have to deliver repetitive products. For a one-off product, more a project, the engineering process will have the manufacturing already in mind. No need for a transition between EBOM and MBOM, it would only slow down the delivery.

Now let´s look at some EBOM-MBOM specifics

EBOM phantom assemblies

PhantomWhen extracting an EBOM directly from a 3D CAD structure, there might be subassemblies in the EBOM due to a logical grouping of certain items. You do not want to see these phantom assemblies in the MBOM as they only complicate the structuring of the MBOM or lead to phantom activities. In an EBOM-MBOM transition these phantom assemblies should disappear and the underlying end items should be linked to the higher level.

EBOM materials

In the EBOM, there might be materials like a rubber tube with a certain length, a strip with a certain length, etc. These materials cannot be purchased in these exact dimensions. Part of the EBOM to MBOM transition is to translate these EBOM items (specifying the exact material) into purchasable MBOM items combined with a fitting operation.

EBOM end-items (make)

For make end-items, there are usually approved manufacturers defined and it is desirable to have multiple manufacturers (certified through the AML) for make end-items, depending on cost, capacity and where the product needs to be manufactured. Therefore, a make end-item in the EBOM will not appear in a resolved MBOM.

EBOM end-items (buy)

For buy end-items, there is usually a combination of approved manufacturers (AML) combined with approved vendors (AVL). The approved manufacturers are defined by engineering, based on part specifications. Approved vendors are defined by manufacturing combined with purchasing based on the approved manufacturers and logistical or commercial conditions

Are EBOM items and MBOM items different?

MBOM-MOBMThere is a debate if EBOM items should/could appear in an MBOM or that EBOM items are only in the EBOM and connected to resolved items in the MBOM. Based on the previous descriptions of the various EBOM items, you can conclude that a resolved MBOM does not contain EBOM items anymore in case of multiple sourcing. Only when you have a single manufacturer for an EBOM item, the EBOM item could appear in the MBOM. Perhaps this is current in your company, but will this stay the same in the future?

It is up to your business process and type of product which direction you choose. Coming back to one-off products, here is does not make sense to have multiple manufacturers. In that case, you will see that the EBOM item behaves at the same time as an MBOM item.

What about part numbering?

clip_image011Luckily I reached the 1000 words so let´s be short on this debate. In case you want an automated flow of information between PLM and ERP, it is important that shared data is connected through a unique identifier.

Automation does no need intelligent numbering. Therefore giving parts in the PLM system and the ERP system a unique, meaningless number you ensure guaranteed digital connectivity.

If you want to have additional attributes on the PLM or ERP side that describe the part with a number relevant for human identification on the engineering side or later at the manufacturing side (labeling), this all can be solved.

An interesting result of this approach is that a revision of a part is no longer visible on the ERP side (unless you insist). Each version of the MBOM parts is pointing to a unique version of an MBOM part in ERP, providing an error free sharing of data.


Life can be simple if you generalize and if there was no past, no legacy and no ownership of data thinking. The transition of EBOM to MBOM is the crucial point where the real PLM vision is applied. If there is no data sharing on MBOM level, there are two silos, the characteristic of the old linear past.

(See also: From a linear world to a circular and fast)

What do you think? Is more complexity needed?



I will be soon discussing these topics at the PDT2015 in Stockholm on October 13-14. Will you be there ?

And for Dutch/Belgium readers – October 8th in Bunnik:


Op 8 oktober ben ik op het BIM Open 2015 Congres in Bunnik waar ik de overeenkomsten tussen PLM en BIM zal bespreken en wat de constructie industrie kan leren van PLM

classificationIn my previous post describing the various facets of the EBOM, I mentioned several times classification as an important topic related to the PLM data model. Classification is crucial to support people to reuse information and, in addition, there are business processes that are only relevant for a particular class of information, so it is not only related to search/reuse support.

In 2008, I wrote a post about classification, you can read it here. Meanwhile, the world has moved on, and I believe more modern classification methods exist.

Why classification ?

searchFirst of all classification is used to structure information and to support retrieval of the information at a later moment, either for reuse or for reference later in the product lifecycle. Related to reuse, companies can save significant money when parts are reused. It is not only the design time or sourcing time that is reduced. Additional benefits are lower risks for errors (fewer discoveries), reduced process and approval time (human overhead), reduced stock (if applicable), and more volume discount (if applicable) and reduced End-Of-Life handling.

An interesting discussion about reuse started by Joe Barkai can also be found on LinkedIn here, including interesting comments

Classification can also be used to control access to certain information (mainly document classification), or classification can be used to make sure certain processes are followed, e.g. export control, hazardous materials, budget approvals, etc. Although I will speak mainly about part classification in this post, classification can be used for any type of information in the PLM data model.

Classification standards

din4000Depending on the industry you are working in, there are various classification standards for parts. When I worked in the German-speaking countries (the DACH-länder) the most discussed classification at that time was DIN4000 (Sachmerkmal-liste), a must have standard for many of the small and medium sized manufacturing companies. The DIN 4000 standard had a predefined part hierarchy and did not describe the necessary properties per class. I haven’t met a similar standard in other countries at that time.

Another very generic classification I have seen are the UNSPC standard, again a hierarchical classification supporting everything in the universe but no definition of attributes.

15926Other classification standards like ISO13399, RosettaNET, ISO15926 and IFC exist to support collaboration and/or the supply chain. When you want to exchange data with other disciplines or partners. The advantage of a standard definition (with attributes) is that you can exchange data with less human processing (saving labor costs and time – the benefit of a digital enterprise).

I will not go deeper into the various standards here as I am not the expert for all the standards. Every industry has its own classification standards, a hierarchical standard, and if more advanced the hierarchy is also supported by attributes related to each class. But let´s go into the data model part.

Classification and data model

clip_image002The first lesson I learned when implementing PLM was that you should not build your classification hard-coded into the PLM, data model. When working with SmarTeam is was very easy to define part classes and attributes to inherit. Some customers had more than 300 classes represented in their data model just for parts. You can imagine that it looks nice in a demo. However when it comes to reality, a hard-coded classification becomes a pain in the model. (left image, one of the bad examples from the past)

1 – First of all, classification should be dynamic, easy to extend.

2 – The second problem however with a hard-coded classification was that once a part is defined for the first time the information object has a fixed class. Later changes need a lot of work (relinking of information / approval processes for the new information).

3 – Finally, the third point against a hard-coded classification is that it is likely that parts will be classified according to different classifications at the same time. The image bellow shows such a multiple classification.


So the best approach is to have a generic part definition in your data model and perhaps a few subtypes. Companies tend to differentiate still between hardware (mechanical / electrical) parts and software parts.

Next a part should be assigned at least to one class, and the assignment to this class would bring more attributes to the part. Most of the PLM systems that support classification have the ability to navigate through a class hierarchy and find similar parts.

When parts are relevant for ERP they might belong to a manufacturing parts class, which add particular attributes required for a smooth PLM – ERP link. Manufacturing part types can be used as templates for ERP to be completed.

This concept is also shared by Ed Lopategui as commented to my earlier post about EBOM Part types. Ed states:

Think part of the challenge moving forward is we’ve always handled these as parts under different methodologies, which requires specific data structures for each, etc. The next gen take on all this needs to be more malleable perhaps. So there are just parts. Be they service or make/buy or some combination – say a long lead functional standard part and they would acquire the properties, synchronizations, and behaviors accordingly. People have trouble picking the right bucket, and sometimes the buckets change. Let the infrastructure do the work. That would help the burden of multiple transitions, where CAD BOM to EBOM to MBOM to SBOM eventually ends up in a chain of confusion.

I fully agree with his statement and consider this as the future trend of modern PLM: Shared data that will be enriched by different usage through the lifecycle.

Why don’t we classify all data in PLM?

There are two challenges for classification in general.

  • The first one is that the value of classification only becomes visible in the long-term, and I have seen several young companies that were only focusing on engineering. No metadata in the file properties, no part-centric data management structure and several years later they face the lack of visibility what has been done in the past. Only if one of the engineers remembers a similar situation, there is a chance of reuse.
  • The second challenge is that through a merger or acquisition suddenly the company has to manage two classifications. If the data model was clean (no hard-coded subclasses) there is hope to merge the information together. Otherwise, it might become a painful activity to discover similarities.


Modern search based applications

There are ways to improve classification and reuse by using search-based application which can index archives and try to find similarity in properties / attributes. Again if the engineers never filled the properties in the CAD model, there is little to nothing to recover as I experienced in a customer situation. My PLM US peer, Dick Bourke, wrote several articles about search-based applications and classification for, which are interesting to read if you want to learn more: Useful Search Applications for Finding Engineering Data

So much to discuss on this topic, however I reached my 1000 words again Sad smile


Classification brings benefits for reuse and discovery of information although benefits are long-term. Think long-term too when you define classifications. Keep the data model simple and add attributes groups to parts based on functional classifications. This enables a data-driven PLM implementation where the power is in the attributes not longer in the part number. In the future, search-based applications will offer a quick start to classify and structure data.




In my earlier posts, I described generic PLM data model and practices related to Products, BOMs en recently EBOM and (CAD) Documents. This time I want to elaborate a little bit more on the various EBOM characteristics.


The EBOM is the place where engineering teams collaborate and define the product. A released EBOM is supposed to give the full engineering specification how a product should behave including material quality and tolerances. This makes it different from the MBOM, which contains the specification of how this product should be manufactured based on exact components and materials.

Depending on the type of product there are several EBOM best practices which I will discuss here (briefly) in alphabetical order:

EBOM & Buy Part

PDM_ERP_AML_AVLUsually, an EBOM consists of Make and Buy parts –an attribute on the EBOM part indicates the preferred approach. Make parts are typically sourced towards qualified suppliers, where Buy parts can be more generic and based on qualified vendors. Engineering specifies who are the approved Manufacturers for the part (AML) and purchasing decides who are the approved Vendors for this part (AVL). In general Buy parts do not need an engineering efforts every time the part is used in a product.

EBOM & CAD related

My previous post already discussed some of the points related to EBOM and CAD Documents. Here I want to extend a little more addressing the close relation between MCAD parts and EBOM parts. In particular in the Engineering To Order industry, there is, most of the time, no standard product to relate to. In that case, Mechanical CAD can be the driver for the EBOM definition and usually EBOM Make parts are designed uniquely. The challenge is to understand similar parts that might exist and reuse them. Classification (and old post here) and geometric search capabilities support the modern engineer. I will come back to classification in a later post

EBOM – Configuration Item

cmiiIn case a product is designed for mass production throughout a longer lifetime, it becomes necessary to manage the product configuration over time. How is the product is defined today and avoid the need to have for each product variant a complete EBOM to manage. The EBOM can be structured with Options and Variants. In that case, having Configuration Items in the EBOM is crucial. The Configuration Item is the top part that is versioned and controlled. Parts below the configuration item, mostly standard parts do not impact the version of the Configuration Item as long as the Form-Fit-Function from the Configuration Item does not change. Configuration Management is a topic on its own and some people believe PLM systems were invented to support Configuration Management.

EBOM – Company Standard Part

Standard Parts are often designed parts that should be used across various products or product lines. The advantage of company standard parts is that it reduces costs throughout the whole product lifecycle. Less design time, less manufacturing setup time and material sourcing effort and potential lower material cost thanks to higher volumes. Any EBOM part could become at a certain moment a Company Standard part and it is recommended to use a classification related to these parts. Otherwise they will not be found again. As mentioned before I will come back to classification.

EBOM – Functional group

Sometimes during the design of a product, several parts are logically grouped together from the design point of view, either because they are modular or because they always appear as a group of parts.

The EBOM, in that case, can contain phantom parts, which do not represent an end item. These phantom parts assist the company in understanding changing one of the individual parts in this functional group.

EBOM – Long Lead

In typical Engineering to Order or Build To Order deliveries there are components on the critical path of the product delivery. Components with a long lead time should be identified and ordered as early as possible during the delivery process. Often the EBOM is not complete or mature enough to pass through all the information to ERP. Therefore Long Lead items require a fast track towards ERP and a special status in the EBOM reflecting its ordering status. Long Lead items are the example where a company can benefit from a precise interaction between PLM and ERP with various status handshakes and approvals during the delivery process

EBOM – Make parts

Make Parts in an EBOM are usually specified by their related model and drawings. Therefore Make Parts usually have revisions but be aware that they do not follow the same versioning of the related model or drawing. A Make Part is in an In Work status as long as the EBOM is not released. Once the model is approved, the EBOM part can be approved or released. Often companies do not want to release the data as long as manufacturing is not completed. This to make sure that the first revision comes out at the first delivery of the product.

EBOM – Materials

In many mechanical assemblies, the designer specifies materials with a particular length. For example a rubber strip, tubing / piping. When extracting the information from the 3D CAD assembly, this material instance will get a unique identifier. Here it is important that the Material Part has an attribute that describes the material specification. In the ideal data model, this is a reference to a Materials library. Next when manufacturing engineering is defining the MBOM, they can decide on material quantities to purchase for the EBOM Material.

EBOM – Part Number

QRThis could be a post on its own. Do we need intelligent part numbers or can we use random generated unique numbers? I have a black and white opinion about that. If you want to achieve a digital enterprise you should aim for random generated unique numbers. This because in a digital enterprise data is connected without human transfer. The PLM and ERP link is unambiguous. Part recognition at the shop floor can be done with labels and scanning at the workstation. There is no need for a person to remember or transfer information from one system or location by understanding the part number. The uniquely generated number make sure every person will have a look at the digital metadata online available. Therefore immediately seeing a potential status change or upcoming engineering change. Supporting the intelligent numbering approach allows people to work disconnected again, therefore not guaranteeing that an error-free activity takes place. People make mistakes, machines usually not.

EBOM – Service Parts

It is important to identify already in the EBOM which parts need to be serviced in operation and engineering should relate the service information already to the EBOM part. This could be the same single part with a different packaging or it could be a service kit plus instructions linked to the part. In a PLM environment, it is important that this activity is done upfront by engineering to avoid later retrieval of the data and work again on service information. A sensitive point here is that engineers currently in the classical approach are not measured on the benefits they deliver downstream when the products are in the field. Too many companies work here in silos.

EBOM – Standard Parts

3dFinally, as I reach already the 1000 words, a short statement about EBOM standard parts. These standard parts, based on international or commercial standards do not need a revision and often they have a specification sheet, not necessary a 3D model for visualization. Classification is crucial for Standard Part and here I will write a separate post about dealing with Standard Parts, both mechanical and electrical.

Concluding: this post we can see that the EBOM is having many facets and based on the type of EBOM part different behavior is expected. It made me realize PLM is not that simple as I thought. In general when defining an EBOM data model you would try to minimize the specific classes for the EBOM part. Where possible, solve it with attributes (Make/Buy – Long Lead – Service – etc.). Use classification to store specific attributes per part type related to the part. Classification will be my next topic as it appears

Feel free to jump on any of the EBOM characteristics for an extended discussion

note: images borrowed from the internet contain links to the original location where I found them. The context there is not always relevant for this post.

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