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).