Understanding SOLIDWORKS BOM Options for Replacing Components

When working with a SOLIDWORKS BOM, there are several options that can help us specify how to manage removed or replaced components.

The two options we will address here are Keep Missing Item/Row and Do not change item numbers. At first glance, it may seem that these settings conflict, but if we take a closer look, we will find that there really isn’t much overlap between them.

SOLIDWORKS BOM Option: Keep Missing Item/Row

Keep Missing Item/Row only applies when the user is replacing a file using the Replace command, or they are using the Save As command on a component of an assembly with the assembly open. When a user replaces a file using one of the two methods above, this option applies.

If the user deletes a file and then inserts a different part to replace that part, this option does not apply. This option controls how SOLIDWORKS manages both the replaced part and its replacement.

Let’s take a look at how this option works. Figure 1 is our starting point for all of the following examples. This SOLIDWORKS BOM has just been inserted and there have been no changes to the assembly since inserting it.

Keep both with new item number for replacement

Let’s look at how the Keep both with new item number for replacement option works.

If we replace item number 2 in the assembly using the Replace command, and then take a look at the SOLIDWORKS BOM, we still have the original item number 2 shown in the table with a quantity of  “-” and we have the replacement component listed as a new item number 9 in the table with a quantity of 1.

Using “Keep both with new item number for replacement”

Keep both with same item number

Now let’s look at how Keep both with same item number works.

If our starting point is the original SOLIDWORKS BOM and we replace item number 2 using the Replace command in the assembly, we still have the original item number 2 shown in the table with a quantity of  “-“. This means we have the replacement component listed as a second line item number 2 in the table with a quantity of 1.

Using “Keep both with same item number”

Keep item number and do not keep replaced component

Now we can look at how Keep item number and do not keep replaced component works.

With this option, we can see that the old item is removed, and the new item takes its place using the same item number 2.

Using “Keep item number and do not keep replaced component”

Assign new item number and do not keep replaced component

Finally, let’s look at the last option, Assign new item number and do not keep replaced component.

With this option, we can see that the old item is removed, and the new item is added in its place in the SOLIDWORKS BOM as item number 9.

Using “Assign new item number and do not keep replaced component”

SOLIDWORKS BOM Option: Do not change item numbers

The option for Do not change item numbers controls the behavior of the item numbers when components are deleted, suppressed, or reordered. Notice that replacing objects isn’t mentioned.

• If we replace a component, the Keep Missing Items/Row options apply.
• If we delete, suppress, or reorder the components, the Do not change item numbers setting applies.

As an example, consider the SOLIDWORKS BOM from the beginning. If we delete item number 2 (the rocker support) from the assembly, this setting determines whether it will renumber the remaining components or reserve the original numbers.

A BOM using “Do not change item numbers”

In the image above, we have deleted item number 2, and we can see that it did not renumber the remaining items in the SOLIDWORKS BOM. If we add a new component to the assembly, the item will be added as item number 9.

Overlap Between SOLIDWORKS BOM Options

For the most part, these two options discussed are useful in different scenarios.

• Keep missing item/Row applies when replacing a part using the Replace command or Save As command.
• Do not change item numbers comes into play when deleting, suppressing, or reordering components.

However, there is a small amount of overlap between these two options:

• If Do not change item numbers is selected and Keep Missing Item/Row is selected using either Keep both with new item number for replacement or Keep both with same item number and a component is deleted from the assembly, the row for that item in the table is kept and the quantity is set to 0, -, or left blank to indicate a null quantity.
• If Do not change item numbers is selected and Keep Missing Item/Row is selected using either Keep item number and do not keep replaced component or Assign new item number and do not keep replaced component, the row will be removed from the SOLIDWORKS BOM.
• If Do not change item numbers is selected and Keep Missing Item/Row is not selected, the row will be removed from the SOLIDWORKS BOM.

To learn more about manipulating a SOLIDWORKS assembly bill of materials, register for an upcoming training class here.