Bill of Materials (BOM) generation in Solidworks - Deep Dive

Overview - Bill of Materials (BOM) generation

What is it?

A Bill of Materials (BOM) is a detailed list of all parts, components, and materials needed to build a product. BOM generation in SolidWorks automatically creates this list from a 3D model or assembly. It helps organize and track every item required for manufacturing. This makes production planning and costing easier and more accurate.

Why it matters

Without BOM generation, teams would manually list parts, risking errors and missing items. This slows down production and increases costs due to mistakes or delays. Automated BOM generation ensures accuracy and saves time, helping companies deliver products faster and with fewer errors. It connects design with manufacturing smoothly.

Where it fits

Before learning BOM generation, you should understand basic SolidWorks assembly modeling and part creation. After mastering BOMs, you can explore advanced topics like custom BOM templates, linking BOMs to ERP systems, and cost analysis dashboards.

Mental Model

Core Idea

A BOM generation automatically extracts and organizes every part and material from a product design into a clear, structured list for manufacturing.

Think of it like...

It's like making a grocery shopping list from a recipe: you list every ingredient needed to cook the dish, so you don't forget anything at the store.

┌───────────────────────────────┐
│        Assembly Model          │
├───────────────┬───────────────┤
│   Part 1      │   Part 2      │
│  (Screw)      │  (Bracket)    │
├───────────────┴───────────────┤
│        BOM Generation Tool     │
├───────────────────────────────┤
│ Part Name │ Quantity │ Material│
│ Screw     │  10      │ Steel   │
│ Bracket   │  2       │ Aluminum│
└───────────────────────────────┘

Build-Up - 7 Steps

1

Foundation

Understanding What a BOM Is

Concept: Learn what a Bill of Materials is and why it is important in manufacturing.

A BOM is a list that shows every part and material needed to build a product. It includes quantities and sometimes other details like material type or part number. This list helps teams know exactly what to buy and assemble.

Result

You can explain what a BOM is and why it is used in product development.

Understanding the purpose of a BOM helps you see why automating its creation saves time and reduces errors.

2

Foundation

Basics of SolidWorks Assemblies

Concept: Learn how parts come together in SolidWorks to form an assembly.

In SolidWorks, you create parts first, then combine them into an assembly. The assembly shows how parts fit and move together. Each part can have properties like name, material, and quantity.

Result

You can open or create an assembly with multiple parts in SolidWorks.

Knowing how assemblies work is essential because BOM generation pulls data from these assemblies.

3

Intermediate

Generating a Simple BOM in SolidWorks

🤔Before reading on: do you think BOMs are created manually or automatically from assemblies in SolidWorks? Commit to your answer.

Concept: Learn how to create a BOM table automatically from an assembly in SolidWorks.

In SolidWorks, open your assembly, then go to Insert > Tables > Bill of Materials. Choose the assembly or drawing view. SolidWorks will list all parts with default columns like part name and quantity. You can place this table in your drawing or assembly.

Result

A BOM table appears listing all parts and quantities from your assembly.

Knowing that SolidWorks can auto-generate BOMs saves you from manual, error-prone listing.

4

Intermediate

Customizing BOM Columns and Formats

🤔Before reading on: do you think you can add custom columns like cost or supplier to a BOM in SolidWorks? Commit to your answer.

Concept: Learn how to add or remove columns and change the appearance of BOM tables.

After generating a BOM, right-click the table and select 'Insert Column' to add new columns like 'Cost' or 'Supplier'. You can also hide columns you don't need. Use properties from parts or custom properties to fill these columns. Formatting options let you change fonts and colors.

Result

A BOM table customized with extra useful information and clear formatting.

Customizing BOMs makes them more useful for different teams like purchasing or costing.

5

Intermediate

Linking BOMs to Custom Properties

🤔Before reading on: do you think BOM data updates automatically if part properties change? Commit to your answer.

Concept: Learn how BOMs reflect changes in part custom properties automatically.

Each part can have custom properties like material, weight, or cost. When you update these in the part file, the BOM updates automatically when refreshed. This keeps your BOM accurate without manual edits.

Result

BOM tables that stay current with part changes, reducing manual work.

Understanding this dynamic link prevents errors from outdated BOM data.

6

Advanced

Creating BOM Templates for Reuse

🤔Before reading on: do you think you must recreate BOM settings every time or can you save templates? Commit to your answer.

Concept: Learn how to save BOM settings as templates for consistent use across projects.

After customizing a BOM, save it as a template file (.sldbomtbt). This template stores column choices, formatting, and sorting. Next time, you can apply this template to new BOMs for consistency and speed.

Result

Reusable BOM templates that save time and ensure standardization.

Templates help teams maintain consistent BOM formats across many products.

7

Expert

Integrating BOMs with ERP and Cost Analysis

🤔Before reading on: do you think BOMs in SolidWorks can connect directly to business systems? Commit to your answer.

Concept: Learn how BOM data can be exported and linked to enterprise systems for cost and inventory management.

SolidWorks BOMs can be exported as Excel or CSV files. These files can be imported into ERP (Enterprise Resource Planning) systems to track inventory and costs. Advanced users automate this export-import process to keep manufacturing and finance in sync.

Result

A smooth flow of BOM data from design to business systems, improving accuracy and decision-making.

Knowing this integration bridges design and business, making BOM generation a key part of product lifecycle management.

Under the Hood

SolidWorks reads the assembly structure and extracts part information like names, quantities, and custom properties. It organizes this data into a table format linked to the assembly file. When parts or properties change, the BOM updates dynamically by refreshing the table. The software uses internal references to maintain this connection.

Why designed this way?

BOM generation was designed to reduce manual errors and save time by automating data extraction from complex assemblies. Early methods were manual and error-prone. Automating BOMs ensures accuracy and consistency, which is critical for manufacturing and supply chain efficiency.

┌───────────────┐
│ Assembly File │
├──────┬────────┤
│ Part │ Quantity│
│ Info │ Custom │
│      │ Props  │
└──────┴────────┘
       │
       ▼
┌─────────────────────┐
│ BOM Generation Logic │
│ - Reads assembly     │
│ - Extracts data      │
│ - Builds table       │
└─────────────────────┘
       │
       ▼
┌─────────────────────┐
│ BOM Table in Drawing │
│ - Displays parts     │
│ - Updates dynamically│
└─────────────────────┘

Myth Busters - 4 Common Misconceptions

Quick: Does a BOM list only the top-level parts or every single component? Commit to your answer.

Common Belief: A BOM only lists the main parts you see in the assembly, not the small components inside.

Reality: A BOM lists every part and sub-part in the assembly, including small screws and washers, unless filtered out.

Why it matters: Missing small components can cause incomplete orders and production delays.

Quick: Do you think BOMs update automatically when you change a part property? Commit to your answer.

Common Belief: Once a BOM is created, it stays static and must be manually updated if parts change.

Reality: BOMs in SolidWorks update automatically when you refresh the table after changing part properties.

Why it matters: Assuming static BOMs leads to outdated information and costly mistakes.

Quick: Can you add any custom information to a BOM easily? Commit to your answer.

Common Belief: BOMs only show fixed columns like part name and quantity; you cannot add custom data.

Reality: You can add custom columns linked to part properties like cost, supplier, or material.

Why it matters: Knowing this allows tailoring BOMs to different team needs, improving communication.

Quick: Is exporting BOM data to business systems a manual, error-prone process? Commit to your answer.

Common Belief: BOM export is always manual and disconnected from business software.

Reality: BOMs can be exported in formats that integrate with ERP systems, and this process can be automated.

Why it matters: Automation reduces errors and keeps design and business data synchronized.

Expert Zone

1

BOM tables can be filtered to show only purchased parts or only manufactured parts, helping different departments focus on relevant data.

2

Custom properties in parts can be linked to BOM columns using exact property names, requiring careful naming conventions to avoid errors.

3

Sorting BOM rows by different columns (like part number or quantity) can reveal assembly priorities or cost drivers, aiding decision-making.

When NOT to use

BOM generation in SolidWorks is not ideal for extremely large assemblies with thousands of parts where specialized PLM (Product Lifecycle Management) software is better. Also, for non-CAD data or service-only products, manual or ERP-based BOMs may be preferred.

Production Patterns

In production, BOMs are often linked to revision control so changes in design automatically update manufacturing documents. Teams use standardized BOM templates for consistency. BOM exports feed into purchasing and inventory systems to automate ordering and stock tracking.

Connections

Enterprise Resource Planning (ERP)

BOM generation outputs data that ERP systems use for inventory and cost management.

Understanding BOMs helps grasp how design data flows into business operations, linking engineering and finance.

Supply Chain Management

BOMs provide the detailed parts list needed to plan procurement and logistics in supply chains.

Knowing BOM structure aids in optimizing supply chain efficiency and avoiding production delays.

Recipe Management in Cooking

Both list ingredients or parts needed to create a final product or dish.

Seeing BOMs like recipes helps appreciate the importance of complete and accurate ingredient lists for success.

Common Pitfalls

#1 Forgetting to refresh the BOM after changing part properties.

Wrong approach:

Generate BOM once and never update it, assuming it stays current.

Correct approach:

After changing part properties, right-click the BOM table and select 'Update' or 'Refresh' to sync changes.

Root cause:

Misunderstanding that BOM tables are dynamic and require manual refresh to show updates.

#2 Adding custom columns without linking them to part properties.

Wrong approach:

Insert a new column in BOM and type data manually, expecting it to update automatically.

Correct approach:

Insert a new column and set its source to a custom property from parts so it updates dynamically.

Root cause:

Not knowing how to connect BOM columns to part metadata.

#3 Assuming BOM only lists top-level parts and ignoring sub-assemblies.

Wrong approach:

Filtering BOM to show only top-level parts and missing components inside sub-assemblies.

Correct approach:

Configure BOM to show all levels or exploded view to include every component.

Root cause:

Lack of understanding of assembly hierarchy and BOM filtering options.

Key Takeaways

A Bill of Materials (BOM) is a complete list of all parts and materials needed to build a product, essential for manufacturing accuracy.

SolidWorks can automatically generate BOMs from assemblies, saving time and reducing errors compared to manual lists.

BOMs dynamically link to part properties, so updating parts updates the BOM when refreshed.

Customizing BOM columns and saving templates helps tailor BOMs for different teams and ensures consistency.

Exporting BOMs to ERP systems connects design data with business operations, improving production and cost management.

Practice

1.

What is the primary purpose of a Bill of Materials (BOM) in SolidWorks?

easy

A. To list all parts and quantities needed for a product

B. To create 3D models of parts

C. To simulate product movement

D. To generate technical drawings automatically

Solution

1. Step 1: Understand BOM definition

   A BOM is a list that details all parts and quantities required to build a product.

2. Step 2: Compare options with BOM purpose

   Only To list all parts and quantities needed for a product correctly describes the BOM's role in listing parts and quantities.

3. Final Answer:

   To list all parts and quantities needed for a product -> Option A

4. Quick Check:

   BOM = List of parts and quantities [OK]

Hint: BOM always lists parts and quantities, not models or simulations [OK]

Common Mistakes:

• Confusing BOM with 3D modeling or simulation
• Thinking BOM creates drawings automatically
• Assuming BOM is only for assembly instructions

2.

Which menu path in SolidWorks is used to insert a Bill of Materials table?

Choose the correct sequence.

easy

A. Tools > BOM > Insert Table

B. Insert > Tables > Bill of Materials

C. File > New > Bill of Materials

D. View > Tables > BOM

Solution

1. Step 1: Recall SolidWorks menu for BOM

   The correct menu path to insert a BOM is under Insert > Tables > Bill of Materials.

2. Step 2: Verify other options

   Options A, B, and D do not match the correct menu sequence for BOM insertion.

3. Final Answer:

   Insert > Tables > Bill of Materials -> Option B

4. Quick Check:

   Insert > Tables > BOM = Correct menu path [OK]

Hint: BOM is under Insert > Tables, not File or Tools [OK]

Common Mistakes:

• Looking under File or Tools menus
• Confusing BOM insertion with drawing creation
• Selecting View menu instead of Insert

3.

Given an assembly with 3 parts: Part A (2 units), Part B (4 units), and Part C (1 unit), what will the quantity column show in the BOM?

Choose the correct quantities for each part.

medium

A. Part A: 2, Part B: 4, Part C: 1

B. Part A: 1, Part B: 1, Part C: 1

C. Part A: 3, Part B: 4, Part C: 2

D. Part A: 2, Part B: 2, Part C: 1

Solution

1. Step 1: Identify quantities from assembly

   The assembly specifies Part A has 2 units, Part B has 4 units, and Part C has 1 unit.

2. Step 2: Match quantities to BOM output

   The BOM quantity column reflects the exact counts of each part in the assembly.

3. Final Answer:

   Part A: 2, Part B: 4, Part C: 1 -> Option A

4. Quick Check:

   Quantities match assembly counts [OK]

Hint: BOM quantity matches assembly part counts exactly [OK]

Common Mistakes:

• Assuming all quantities default to 1
• Adding quantities incorrectly
• Mixing up part counts

4.

When generating a BOM, a user notices the quantity column shows all 1s, even though some parts have multiple units. What is the most likely cause?

medium

A. The BOM is set to 'Parts Only' instead of 'Top-level only'

B. The assembly is missing part references

C. The BOM is set to 'Top-level only' instead of 'Parts Only'

D. The drawing sheet is not active

Solution

1. Step 1: Understand BOM quantity settings

   'Top-level only' BOM counts each part once regardless of quantity, showing 1 for all.

2. Step 2: Identify correct setting for quantities

   Setting BOM to 'Parts Only' aggregates quantities correctly, showing actual counts.

3. Final Answer:

   The BOM is set to 'Top-level only' instead of 'Parts Only' -> Option C

4. Quick Check:

   BOM setting affects quantity display [OK]

Hint: Use 'Parts Only' BOM to show correct quantities [OK]

Common Mistakes:

• Confusing 'Top-level only' with 'Parts Only'
• Assuming missing references cause quantity errors
• Not checking BOM property settings

5.

You want to create a BOM that updates automatically when parts are added or removed from your assembly. Which approach should you take?

Choose the best practice for dynamic BOM updates.

hard

A. Manually create a BOM in Excel and update it after changes

B. Create BOM only after finalizing the assembly to avoid updates

C. Export BOM once and reuse the static file for all assemblies

D. Insert a linked BOM table in the assembly drawing that updates with changes

Solution

1. Step 1: Understand dynamic BOM update methods

   Linked BOM tables in SolidWorks drawings update automatically when assembly changes.

2. Step 2: Evaluate options for best practice

   Manual Excel or static exports do not update automatically; waiting until final assembly delays updates.

3. Final Answer:

   Insert a linked BOM table in the assembly drawing that updates with changes -> Option D

4. Quick Check:

   Linked BOM = automatic updates [OK]

Hint: Use linked BOM tables for automatic update in drawings [OK]

Common Mistakes:

• Relying on manual Excel BOMs
• Using static exports that don't update
• Delaying BOM creation until assembly is final