A BOM is a structured list of all the sub-assemblies, assemblies and parts that are necessary to produce a shippable completed product. The information stored in a BOM includes costs, part numbers, part descriptions and quantity requirements.
Sometimes the balloon numbering in a drawing doesn’t follow the Bill of Materials (BOM) item numbers. There are a couple of reasons why this might happen.
Part Numbers
In a BOM, part numbers indicate the parts and assemblies that make up a product. They are used to calculate costs, mass and to plan purchasing. They are also useful in identifying parts and determining what stages they’re at in the design process.
You can change how part numbers are displayed in a BOM by setting the Part Number Display Options in the BOM Properties dialog box. You can choose to use a stock number assigned by your company, the configuration name of a subassembly, or any user-specified value. You can also choose to display the BOM document name as the part number.
When you add a BOM saved with an assembly into a drawing, the item numbers that appear in the BOM display in the balloons for the assembly views in the drawing. This may cause issues when you have multiple BOMs in a single drawing, especially when the part/assembly has more than one configuration.
To correct this issue, select the part or assembly document in which you want to change the part number display options and then click Tools > Options. In the Document Properties dialog box, select the option to use a stock number or configure the option to use the BOM document name as the part number for derived configurations. You can also select the option to use a user-specified value for part numbers in the Configuration Manager for a subassembly or part that has more than one configuration.
Units of Measurement
The unit of measurement in a BOM is a critical factor for planning and tracking materials. It helps in making sure that you have the right quantities of the correct parts at the proper times for assembly and shipping. If you have the wrong units, you may end up with shortages or overages that can slow production or even cause it to halt completely. This can cost your company money in terms of lost productivity and additional expediting charges to get the material in quickly.
When setting up a BOM, you can use the Custom Properties dialog box to set the UNIT_OF_MEASURE custom property. This is a protected variable that controls the BOM quantity field. To change this value, simply hover over the BOM column and use the Edit multiple property values dialog box to select the unit of measure (shown in Figure 3).
Creating a BOM is important for several reasons. A BOM contains information that is essential for manufacturing resource planning (MRP) and product costing. It also helps ensure that the manufacturer has all the necessary materials to assemble a completed product. Creating and managing a BOM is time-consuming, but it’s also essential to the success of your business.
Having a well-organized BOM will reduce the risk of costly mistakes. Without a BOM, errors can occur during the process of creating and assembling a product, such as ordering the incorrect quantity of materials or forgetting to include labor. The result could be a costly mistake that affects the entire product design or manufacturing process.
Reference Designator
As with other professional 3D Mechanical CAD software, SolidWorks includes a tool to create a bill of materials. The BOM is a comprehensive list of all components used in a CAD assembly or drawing. It provides important information that can help a company plan purchasing or manufacturing operations. It also makes it easier for a contractor or shop to make the required changes to a design.
The BOM can be displayed as a table or balloon in an assembly drawing. It can be automatically updated when a component is added, deleted or replaced. This feature is enabled by selecting the “Automatically update BOM” option under Tools > Options > Document Properties > Tables > Bill of Materials. The BOM can also be linked to a referred view. However, if the referred view is modified, the BOM may not automatically update.
A BOM can be organized in a single level or multiple levels of subassemblies. The top-level product sits at the top of the list, while the costs, part description, and quantities are shown below it. A multilevel BOM is more involved and requires a greater degree of detail than a single-level BOM. However, it offers advantages such as organization, collaboration, reuse and configurations.
To avoid confusion during production, it is important to use a clear reference designator for each item in the BOM. This helps to identify the parts and subassemblies that belong to each piece of a product. It also helps to prevent miscommunication and misunderstandings.
Notes
A BOM is a super important list of all the parts that go into making a CAD drawing. It shows the quantity of each part, the unique part number, and a description. It also identifies the units of measurement used. This helps to ensure that each part is built the way it was designed, which is vital for manufacturing. It also enables efficiencies in planning, purchasing and manufacturing.
It is essential to assign a unique part number to each part and assembly so that they can be easily retrieved and referenced in the design. This will help to avoid confusions, mistakes and inventory mismanagement. You can also use the BOM to track the status of each part in a product. For example, you can mark a part as “In Production” to indicate its current state. You can also add notes to the BOM to provide additional information.
You can create a table-based bill of materials in SolidWorks by inserting it into the drawing of an assembly or a part. A table-based BOM is more compact and easier to read than a spreadsheet-based one. It also allows you to update a BOM automatically whenever you make changes to components, if the ‘Automatically update BOM’ option is selected in the BOM Properties. If this is not the case, you will have to manually add the changes to each component.