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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.

The EBOM

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)

 

 

To understand our legacy in the PLM-domain, what are the types of practices we created, I started this series of posts: Learning from the past to understand the future. My first post (The evolution of the BOM) focused on the disconnected world between engineering  – generation of drawings as a  deliverable – and execution MRP/ERP – the first serious IT-systems in a company.

At that time, due to minimal connectivity, small and medium-sized companies had, most of the time, an informal connection between engineering and manufacturing. I remember a statement at that time, PLM was just introduced. One person during a conference claimed:

“You guys make our lives so difficult with your systems. If we have a problem, we gather around the machine, and we fix it.”

PLM started at large enterprises

Of course, large enterprises could not afford such behavior as they operate globally. The leading enterprises for PDM/PLM were the Aerospace & Defense and Automotive companies. They needed consistent processes and formal ways of working to guarantee quality output.

In that sense, I was happy with the reaction from Jean-Jacques Urban-Galindo, who shared in the LinkedIn comments a reference to a relevant chapter of John Stark’s PLM book. In the pdf describing the evolution of CAD / PDM / PLM at PSA. Jean-Jacques was responsible at that time for Responsible for the re-engineering of the Product & Process Engineering processes using digital tools (CAD/CAM, DMU, and more).

Read the PSA story here: PLM at GROUPE PSA. It describes nicely where 3D CAD and EBOM are coming in.  In large enterprise like PSA, the need for tools are driven by the processes. When you read it to the end, you will also see the need for a design and a manufacturing view. A topic I will touch in future posts too.

The introduction of 3D CAD in the mid-market

Where large automotive and aerospace companies already invested in (expensive) 3D CAD hard and software, for the majority of the midsize companies, the switch from 2D CAD (AutoCAD mainly) towards 3D CAD (SolidWorks, Solid Edge, Inventor) started at the end of the 20th century.

It was the time that Microsoft NT became a serious platform beside the existing mainframe and mini-computer based CAD-systems. The switch to PCs went so fast that the disruption from DEC (Digital Equipment Company) is one of the cases discussed by Clayton Christensen in his groundbreaking book: The Innovator’s dilemma

3D CAD introduced a lot of new capabilities, like DMU (Digital Mock-Up), for clash detection, and above all, a better understanding of a product’s behavior. The introduction of 3D CAD introduced a new set of challenges to be resolved.

For example, the concept of reusing 3D CAD parts. Mid-market companies, most of the time, are buying productivity tools. Can I design my product faster and with higher quality in 3D instead of using only the 2D definitions?

Mid-market companies usually do not redesign their business processes – no people available for strategy – the pain of lack of strategy is felt in a different way compared to large enterprises—a crucial differentiator for the future of PLM.

Reuse of (3D) CAD parts / Assemblies

In the 2D CAD world, there was not so much reuse of CAD parts. Standard parts were saved in libraries or generated on demand by parametric libraries. Now with 3D CAD, designers might spend more time to define the part. The benefits come from the reuse of small sub-assemblies (modules) into a larger product assembly. Something not relevant in the 2D CAD world.

As every 3D CAD part had to have a file name, it became difficult to manage the file names without a system. How do you secure that the file with name Part01.xxx is unique? Another designer might also create an assembly, where the 3D CAD tool would suggest Part01.xxx as the name. And what about revisions? Do you store them in the filename, and how do you know you have the correct and latest version of the file?

Companies had already part naming rules for drawings, often related to the part’s usage similar to “intelligent” numbers I mentioned in my previous post.

With 3D CAD it became a little more complicated as now in electronic formats, companies wanted to maintain the relation:

Drawing ID = Part ID = File Name

The need for a PDM-system,

If you look to the image on the left, which I found in one of my old SmarTeam files, there is a part number combined with additional flags A-A-C, which also have meaning (I don’t know ☹ ) and a description.

 

The purpose of these meaningful flags was to maintain the current ways of working. Without a PDM-system, parts of the assembly could be shared with an OEM or a supplier. File-based 3D CAD without using a PDM-system was not a problem for small and medium enterprises.

The 3D CAD-system maintained the relations in the assembly files, including relations to the 2D Drawings. Despite the introduction of 3D CAD, the 2D Drawing remained the deliverable the rest of the company or supply chain, was waiting for. Preferably a drawing containing a parts list and balloon numbers, the same as it has been done before.  Why would you need a PDM-system?

PDM for traceability and reuse

If you were working in your 3D CAD-system for a single product, or on individual projects for OEMs, there was no significant benefit for a PDM-system. All deliveries needed for the engineering department were in the 3D CAD environment. Assembly files and drawing files are already like small databases, containing references to the source files of the part (image above).

A PDM-system at this stage could help you build traceability and prevent people from overwriting files. The ROI for this part only depends on the cost and risks of making mistakes.

However, when companies started to reuse parts or subassemblies, there was a need for a system that could manage the 3D models separately. This had an impact on the design methodology.

Now parts could be used in various products. How do you discover parts for reuse, and how do you know you have the last released version.  For sure their naming cannot be related anymore to a single product or project (a practice still used a lot)

This is where PDM-systems came in. Using additional attributes per file combined with relations between parts,  allowing companies to structure and deliver more details related to a part. A detailed description for internal usage, a part type (classification), and the part material were commonly used attributes. And not to forget the status and revision.

For reuse, it was important that the creators of content had a strategy to define a part for future reuse or discovery. Engineerings were not used to provide such services, filling in data in a PDM-system was seen as an overhead – bureaucracy.

As they were measured on the number of drawings they produced, why do extra work with no immediate benefits?

The best compromise was to have the designer fill in properties in the CAD-file when creating a part. Using the CAD-integration with the PDM-system could be used to fill attributes in the PDM-system.

This “beautiful” simple concept lead later to a lot of complexity.

Is the CAD-model the source of data, meaning designers should always start from CAD when designing a product. If someone added or modified data in the PDM-system, should we open the CAD-file to update some properties? Changing a file means it is a new version. What happens if the CAD-file is released, and I update some connected attributes in PDM?

To summarize this topic. Companies have missed the opportunity here to implement data governance. However, none of the silos (manufacturing preparation, service) recognized the need. Implementing new tools (3D CAD and PDM) did not affect the company’s way of working.

Instead of people, processes, tools, the only focus was on new tools and satisfying the people withing the same process.

Of course, when introducing PDM, which happened for mid-market companies at the beginning of this century, there was no PLM vision. Talking about lifecycle support was a waste of time for management. As we will discover in the future posts, large enterprises and small and medium enterprises have the same PLM needs. However, there is already a fundamentally different starting point. Where large enterprises are analyzing and designing business processes, the small and medium enterprises are buying tools to improve the current ways of working

The Future?

Although we have many steps to take in the upcoming posts, I want to raise your attention to an initiative from the PLM Interest Group together with Xlifecycle.com. The discussion is about what will be PLM’s role in digital transformation.

As you might have noticed, there are people saying the word PLM is no longer covering the right context, and all kinds of alternatives have been suggested. I recommend giving your opinion without my personal guidance. Feel free to answer the questionnaire, and we will be all looking forward to the results.

Find the survey here: Towards a digital future: the evolving role of PLM in the future digital world

 

Conclusion

We are going slow. Discovering here in this post the split in strategy between large enterprises (process focus) and small and medium enterprises (tool focus) when introducing 3D CAD. This different focus, at this time for PDM, is one of the reasons why vendors are creating functions and features that require methodology solving – however, who will provide the methodology.

Next time more on 3D CAD structures and EBOM

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