A manufacturer’s success hinges on efficiency and precision. And these factors directly influence production costs, product quality, and timely deliveries.
Having streamlined processes cuts waste and saves time, while precision guarantees top-notch quality and dependability. To reach those goals, you need a recipe for success — like a bill of materials (BOM) detailing all the materials you need. Luckily, a multi-level BOM tells you everything you need in every phase of production to make complex projects simpler.
This guide explores multi-level BOMs, looking at their advantages, how to implement their techniques, and how they streamline manufacturing operations.
What is a multi-level BOM?
BOMs list everything required to manufacture a product, including the names and quantities of raw materials, parts, and subassemblies. They often have descriptions, measurements, and part numbers to create a comprehensive blueprint for production.
Multi-level BOMs, also called indented BOMs, represent the manufacturing stages to give more detail into the process. They break down the components and subassemblies required for a final product. This level of detail facilitates efficient production planning, quality control, and regulatory compliance.
Understanding subassembly
In a multi-level BOM in manufacturing, a subassembly is a building block for a more complex, higher-level assembly. It might be an intermediate good — something that could be sold independently or used in production — with a unique manufacturing process.
An auto manufacturer needs to put together components of a vehicle before finishing a car. The team might build the seats and engine on another production line before they’re combined to create the final product.
Subassembly streamlines operations by allowing workers to focus on particular parts. Workers might not even move between lines. Instead, they build the same part every day and send it to the next production stage. This specialization simplifies error-checking procedures and boosts product quality.
The multi-level BOM structure
Multi-level BOMs are usually represented as a tree for an organized hierarchical overview. The final product is at the top of the tree, and subassemblies are in the lower levels. Each level should detail the necessary parts, quantities, specifications, and assembly processes.
This visualization helps you understand the essential role of each component within a production process and any dependencies. For example, you might need to assemble the radio before you can finish a car console. The BOM would show this.
BOM levels
BOM levels show the hierarchy of components within a product, making it easy to understand how each part fits into the final assembly. Here’s an example of different levels:
- Level 0: The final product, or the end item delivered to the customer, composed of all the necessary assemblies and components.
- Level 1: Major assemblies or subassemblies consisting of various parts and subcomponents. They represent the first breakdown from the final product and include essential functions or structures.
- Level 2: Subcomponents of Level 1 assemblies, or the individual parts and elements that make up the major assemblies. They’re more detailed components that combine to form Level 1 subassemblies.
- Level 3: A multi-level BOM can include as many levels as you need, with a new level for each subassembly.
Indented BOM
An indented BOM represents the hierarchy of each BOM level to make the manufacturing process as clear as possible. Each subcomponent is indented under the parent component, highlighting the intricate relationships and dependencies between various parts.
For a product like a car, a simplified section of the structure might look like this:
0: Car
-> 1: Engine
-> 2: Pistons
-> 1: Body
-> 2: Seats
-> 2: Radio
This example demonstrates how the engine and body are subassemblies of a car, each indented to signify they’re Level 1. Under the engine and the body, components like seats, pistons, and a radio are indented to Level 2 to indicate they require yet another subassembly.
Types of BOM
Understanding the different BOM types provides a solid foundation for optimizing production. Each type includes specific details on the required parts and assembly instructions, but they might focus on different workflows:
- Engineering Bill of Materials (eBOM): The eBOM, created in the product design phase, includes the parts and assemblies necessary from an engineering and design perspective. It focuses on the technical requirements for building a quality product.
- Manufacturing Bill of Materials (mBOM): The mBOM builds on the eBOM by adding all the extra details needed for the manufacturing process, like assembly instructions, necessary tools, and packaging materials. This allows the production team to fully understand all the requirements for manufacturing the final product.
- Configurable Bill of Materials (cBOM): Designed for products with multiple variants and configurations, the cBOM allows you to easily customize products to meet customer requirements while handling the complexity of product options.
- Sales Bill of Materials: This type of BOM is for the sales and marketing departments to show the parts sold as part of a product kit or assembly. It helps these teams effectively communicate what customers will receive with a purchase.
- Service Bill of Materials (sBOM): The sBOM gathers all the necessary parts for maintenance and repair, making post-sales customer support smoother and more effective.
Best practices for implementing and managing multi-level BOMs
To significantly improve the reliability and functionality of your BOMs, follow these best practices:
1. Define the product structure
Clearly outline the product’s hierarchical structure by detailing every assembly, subassembly, and individual component required to complete it.
If the product is a bicycle, start by identifying Level 1 assemblies like the frame, wheels, and drivetrain. Break down each assembly into subassemblies or components, such as the frame with handlebars, seat post, and fork. Finally, show how these components fit together to build the complete bicycle.
2. Standardize naming conventions
Implement consistent and standardized naming conventions for all parts and components. This eliminates confusion, ensures uniformity, and facilitates easy referencing and cross-referencing throughout the BOM.
Instead of generic terms like “small screw,” get specific with descriptors and part numbers like “Screw_Hex_4mm_M3_Aluminum.” This helps avoid mix-ups and streamlines the identification of components at any level.
3. Use detailed descriptions
Provide comprehensive descriptions for each part, component, and finished product. This should cover specifications such as size, weight, materials, dimensions, and other relevant technical details. Descriptions help identify the correct parts and ensure they meet the required standards.
Having descriptive titles, like the screw above, makes it easier for you to find a product at a glance. Include all necessary details of how those parts are used in manufacturing, like the quantities of each part, unique part numbers, assembly instructions, sources for raw materials, and projected production timelines. This ensures the production process is well-documented and easily accessible.
4. Include labor costs
At different stages of product development, it may be important to include labor and material costs for a wider understanding of the total manufacturing cost. Adding these costs supports precise budgeting and setting the right price as the item approaches production.
For instance, a company producing ceramic mugs would calculate the cost of raw materials per mug. Then, they would add labor costs for creating and packaging the mugs. Added together, these numbers provide the total manufacturing cost for each ceramic mug:
Ceramic Mug
Product: Ceramic Mug
Total production cost: $7.00
A. Body
– Material cost: $1.00
– Labor cost: $2.00
– Total cost: $3.00
B. Handle
– Material cost: $0.50
– Labor cost: $1.50
– Total cost: $2.00
C. Glazing
– Material cost: $0.50
– Labor cost: $1.50
– Total cost: $2.00
5. Regularly update and review
Check and update the BOM routinely to ensure all information is accurate, including changes in design, materials, processes, or supplier information.
If your company switches to a new supplier for a component, update the BOM to show this change. You’ll know the part’s origin and who to contact if you receive faulty products or need to reorder more.
6. Integrate with your inventory management system
Integrating the BOM with your Enterprise Resource Planning (ERP), Material Requirements Planning (MRP), or inventory management systems boosts inventory control and enhances production planning. These integrations ensure that data is synchronized across the organization, making BOM details available across departments and easy to update.
7. Collaborate across departments
Engage teams from various departments, such as engineering, manufacturing, procurement, and quality assurance, in the development and maintenance of the BOM. Each team might rely on a different section of the BOM in their quality control checks. Confirming the accuracy of the BOMs each team uses guarantees precision and thoroughness.
Support your multi-level BOM management with Fishbowl
Having access to the parts you need — when you need them — is crucial to using a BOM effectively. Fishbowl can transform your inventory management to simplify the complexities of BOMs and keep raw materials on hand. Low stock alerts, automatic reorder points, and visibility into inventory allocation all guarantee you have the right materials where you need them.
Schedule a demo with Fishbowl to revolutionize your inventory management and production processes today.