The phrase “Bill of Materials” is often unsettling to supply chain professionals, not because of what the actual document is, but because of the time and mindfulness that goes into managing it.
By definition, the Bill of Materials (BOM) is a list of the raw materials, sub-assemblies, intermediate assemblies, sub-components, parts, and the quantities of each needed to manufacture a product. In essence, a BOM is the blueprint of a product and is critical to every aspect of its life cycle, from procurement and production control, to logistics and inventory management. A BOM can range from a small assembly such as a simple cap assembly, to an entire vehicle, possibly even consisting of multiple mini-BOMs. It has parent and child parts, and an indentation scheme, accordingly.
Managing and maintaining any BOM is challenging for organizations due to different variables like program timing, complexity, design changes, communication, and process flow.
It poses ongoing problems which could appear in the form of, but not limited to:
- Transferring information from an engineering BOM into a manufacturing or purchasing BOM
- The duplication of changes or improper maintenance of obsolete parts
- Regrouping parts across products, or re-ordering the grouping sequence to reflect the assembly of intermediate phantom sub-assemblies
- Facilitating a platform definition for product configurability
- Change management
- Establishing traceability for items along product life cycle
- Reusing a sub-assembly without modifying its fit-form-function
So, before tackling any BOM, be aware of all facets of the part and assembly to determine the most appropriate method for BOM management for your company.
4 Tips for Better BOM Management
1. Create an Effective BOM
Creating a BOM is rarely an issue, however, creating an effective BOM is where the difficulty lies. In order to produce successful BOM management, a BOM must be created with all viewing parties in mind. It must be created early in the product life cycle to capture anything and everything that is required for the product.
Again, think of a BOM as a product’s blueprint. The proper functions and categories, whether automated or manual (using Excel), must be included, and anything that describes the product from beginning to end should be included.
Absolutely necessary categories to include are: BOM level (parent vs. child parts), part number, part description, quantity per vehicle, and revision level. Highly recommended categories include: product lead, drawing/CAD availability, supplier/alternate supplier(s), quote(s) and timing information, Plan For Every Part (PFEP), and production control.
Effective and early creation leads to a robust BOM, which in turn leads to successful BOM management.
Automation of a BOM is one of the most important factors to ensure successful BOM management. Automation leads to traceability of the parts and product. This traceability then leads to accountability.
In a scenario where multiple departments manage different BOM’s for the same end-product, an automated platform can act as a conduit for information and find alignment and identify discrepancies between them. Using multiple BOMs increases complexity, yet it’s a fairly common practice for different departments to have separate versions of them (i.e. engineering, manufacturing, or purchasing).
In tandem with traceability, automating a BOM through one of the many systems available also allows for bolt-on capability, whether it be to an MRP or PLM system. This automation leads to less errors frequently seen with manual processes, in addition to simplifying and expediting maintenance efforts.
We’re all lacking time these days, so a system that’s easy to use and that maximizes efficiency is a key contributor to successful BOM management.
3. Information Flow
The flow of information is a critical part of BOM Management and will make or break the process. Proper communication between all parties, viewing or editing the BOM, is a must.
To produce the best BOM clarity, an organization should limit the number of people who can edit the BOM to as few as possible. Anyone should have the capability to view the BOM, however, only a select few should be able to edit it. There also needs to be an owner, or “Admin”, who delegates this visibility and the responsibilities of contributors. This way, there’s full accountability for who makes changes, and when.
Information must navigate the proper channels to make it correctly into the BOM. Again, there may be numerous departments involved in this flow of data (design, engineering, manufacturing, purchasing, quality, etc.), so limiting the number of editors in each department is essential.
A “change log” should be included as part of the change visibility tracking. If the BOM is automated, then this tracking will automatically show details regarding when a category of the product was changed, for example, and by whom. If it’s not automated, then the process will be more manual and could lead to the potential errors.
Visibility, good communication, and ownership lead to proper information flows, which ultimately lead to successful BOM management.
4. Change Management
In any product life cycle there are usually multiple changes, and for some programs or products, this will be more common than for others. These changes can happen at any point in time throughout the product’s life (from design to prototype, to launch). This change management process goes hand-in-hand with a proper information flow, so all parties must effectively communicate when there’s a change relating to the product. This could be anything from a simple ECR Log to a thorough change process that describes every aspect of the change.
These changes must be properly implemented in the BOM by the appropriate party because there is plenty of room for error when revision levels aren’t captured properly. This may lead to incorrect parts being entered on purchase orders issued to suppliers, or receiving outdated or wrong parts from suppliers. Proper approvals and signoffs should be required in any change management process, and then input correctly into the BOM by designated individuals only.
Another area that troubles many organizations is the proper maintenance of obsolete products. When a product becomes obsolete, it must be handled appropriately through the change management process and omitted from the BOM accordingly. The change process, if designed properly, will track this visibility, so you’ll always have a history of a product, whether it’s changed or made obsolete, and what it’s replaced by (if anything).
The BOM serves as the blueprint of a given program or product and it must be developed and managed with precise detail. Deciding what data to capture, who can make changes, and how to track these changes are vital elements to consider when creating a BOM, and investing the time to design a BOM management process will produce the highest level of clarity and the most efficient communication amid team members, across departments. This reduces the potential for errors in the BOM while simultaneously increasing the quality and value of its information, resulting in the execution of successful BOM management and ultimately, a successful product launch.