A basic BOM has several attributes to it – part number, component description, quantity, unit of measure – at a minimum.  More complex BOMs will utilize other product attributes.

An accurate BOM is critical to successful production, as the entire organization from sourcing to engineering to production consume the data that is in the BOM.

• Incorrect BOMs lead to confusion,
• reduced productivity,
• increased costs, and
• higher levels of stress across the organization.

This is especially true as supply chains become more complex, due to globalization and initiatives to make design and manufacturing more disparate and less vertically integrated.

BOM Routings

The “cook settings” for a product – how the ingredients are processed and how they route through the different areas of a factory – are typically covered in other documents such as routings and work instructions. 

Routings consist of the operation sequence, work center, and runtime of each sequence – how the materials orbit through the plant to the different lines and machines.  Work instructions tell a particular operator/machine what the inputs and outputs of that station are. 

BOMs can also be used to control variants.  Electric Buses, as an example, may have several versions that are very close to one another, but essentially re-configured by each order. The only difference from one to the other may be something simple – such as minor interior changes.  The BOM helps control these variations. This is especially important for the use of configurable (or configure-to-order (CTO)) products, as it allows the cost and lead times to be held down by reusing the same components. 

Attributes of a BOM

• • • Level
    • Part number
    • Purchased or manufactured
    • Phase (i.e. design, approved, to be approved, in production, obsoleted, service only)
    • Description
    • Quantity
    • UOM (unit of measure) – including bulk items such as glue and wires which are “as required”
    • Routing (how it is routed through a factory)
    • Variant (which version of the product includes these components
    • Cost
    • Supplier
    • BOM revision and date

Managing BOMs that are more than parts

Today’s electric vehicles are not like the vehicles of the past—they are overflowing with electronics, all of which need software power. A supplier that builds a vehicle’s braking system, for example, will need to keep track of firmware revisions and additional software that collaborates with a vehicle’s dashboard.

Even if a supplier doesn’t engage with the software themselves—perhaps they collaborate with another technical firm in a different location and they need to ensure that changes to the hardware are reflected in the codebase, and vice versa; the enormity and complexity is increasing more and more each day.

Compliance with the BOM

Automakers are notorious for demanding high compliance hurdles for their suppliers because in order to launch a vehicle worldwide, an incredible number of compliance requirements must be met.

They often require suppliers to maintain ISO 9001 certifications, which PLM systems are capable of helping track, in addition to whatever other systems they might deem necessary.

By using BOM management tools, stakeholders will understand exactly when and how any compliance issue is triggered so that they can immediately start to make the necessary revisions.

Added together, the number of BOMs involved is huge.

It’s clear that successful vehicle product realization at these volumes requires extremely robust systems to have any chance of success. The bottom line is that this is closely linked to how well a company will succeed in business.

It’s argued these parts are the most crucial factors in creating vehicle profitability

Creating successful configuration strategies and BOM “mathematics” needed for world-class success in the face of constant and dramatic changes in product realization being imposed by new technologies is the game! 

BOM types

There are various BOM types:

• Engineering BOM (EBOM)– BOM based on product as-designed
• Manufactured BOM (MBOM) – BOM based on manufactured version of the product
  • All the materials in the EBOM
  • Packaging materials
  • Support materials not called out in EBOM
  • Production BOM (PBOM) – BOM based on production requirements; this is the MRP version 
    • All materials in MBOM
    • Lead Times
    • Costs
    • Routings (instructions on how the materials move through the plant)
    • Work Instructions (instructions on what activity is happening at a particular station)
    • Configuration BOM (CBOM)– this is for config-to-order products, such as more commercial facing EVs
      • Configurator with knowledge built in to allow product to be customized to the exact specifications required by the customer
      • Service BOM (SBOM) – includes materials required to install or service a product in the field

Building the BOM

Utilizing Catia/Solidworks 3D CAD systems file reference the components that are used in the assembly.  In doing so, the system by default captures much of the EBOM. This digital BOM is the key to an effective BOM management strategy.

Some components – such as screws, washers, glue etc are frequently not captured in the 3D CAD assembly file. In addition, the BOM tables generated inside the assembly file can easily be exported to a MRP system, ensuring that the EBOM contribution to the MBOM is as accurate as engineering can provide.  This ensures the BOMs are aligned with one another with a “single source of truth,” unidirectional approach.

80% of the cost of a product are captured in the design phase. Exporting design data as a BOM and aligning BOMs at this crucial phase is a strong way of enhancing BOM excellence.

Tips on Building Better BOMs

Most OEMs and the new ACES designers/builders are challenged by bringing through the much needed EV at a cost-effective price

Unidirectional BOMs: 

Using Catia/Solidworks to drive the EBOM, and then the EBOM to drive the MBOM ensures the accountability at each level of the BOM resides with the contributor. Each level only contributes what they are responsible for – and consumes the BOM from the previous contributor. 

Collaboration across the consumers/stakeholders:

Bringing in all consumers/stakeholders early on with the 3DEXPERIENCE Platform, such as sourcing/purchasing, supply chain, manufacturing engineering, production, service personnel, and suppliers is essential in speeding up the overall process. BOMs delivered to them addresses the needs of the organization in order to maximize productivity.   

Product Data Management Systems (PDM)

Collaborative PDM systems blended across 3DEXPERIENCE, Enovia, Catia & Solidworks allow the very best contribution to ensure they are working with the latest version of a file. Nothing aggravates engineers more and slows market introduction than to work for weeks designing a product, only to find out they design around a previous version of an adjacent component.  

Supply Chain Intelligence

A good BOM system will manage supply chain disruption, allowing engineers to quickly determine if work around can be created and at the same time updating the BOM. Ensure that the BOM system captures data in a way that the supply chain organization can review and implement flexibility techniques to minimize risk to the supply chain

Economies of scale

Detailed and intelligent BOMs allow the highlighting of details for facilitating reuse. Search functions inside systems allow users to search based on the BOM attributes, allowing the reuse of components and preventing the need to purchase similar components that need to be requalified.  Organizations should spend some time reviewing the attributes in their BOMs and challenge them to ensure that they are capturing all the relevant parameters that the organization my want to search or specify based on.

No one said it was easy!

Creating a profitable EV, like to creating a Michelin Restaurant was never going to be easy, but a “Michelin Starred BOM” makes one of the greatest differences in the journey.

Starting afresh, without legacy is good and bad, but as you can see some intelligent historical data, when aptly applied to a new EV design can make a huge difference.