How to: Work with Bills of Material

Article
12/01/2017

You use bills of materials (BOMs) to structure parent items that must be assembled or produced by resources or machine centres from components. An assembly BOM can also be used to sell a parent item as a kit consisting of its components.

Assembly BOMs or Production BOMs

You use assembly orders for making end items from components in a simple process that can be performed by one or more basic resources, which are not machine or work centres, or without any resources. For example, an assembly process could be to pick two wine bottles and one coffee sack and then pack them as a gift item.

An assembly BOM is the master data that defines which component items go into an assembled end item and which resources are used to assemble the assembly item. When you enter an assembly item and a quantity in the header of a new assembly order, then the assembly order lines are automatically filled according to the assembly BOM with one assembly order line per component or resource. For more information, see Assembly Management.

Assembly BOMs are described in this topic.

You use production orders for making end items from components in a complex process that requires a production routing and work or machine centres, which represent production capacities. For example, a production process could be to cut steel plates in one operation, weld them in the next operation, and paint the end item in the last operation. For more information, see Manufacturing.

A production BOM is the master data that defines a production item and the components that go into it. for assembly items, the production BOM must be certified and assigned to the production item before it can be used in a production order. When you enter the production item on a production order line, either manually or by refreshing the order, then the production BOM content becomes the production order components. For more information, see How to: Create Production BOMs.

The concept of resources in production is much more advanced than in assembly management. Work centres and machine centres function as resources, and production steps are represented by operations that are assigned to resources in production routings. For more information, see How to: Create Routings.

Both assembly orders and production orders may be linked directly to sales orders. However, you can only use assembly orders to customise the end item directly for a customer request with the sales order.

To create an assembly BOM

To define a parent item that consists of other items, and potentially of resources required to put the parent together, you must create an assembly BOM.

Assembly BOMs usually contain items but can also contain one or more resources that are required to put the assembly item together.

Assembly BOMs can have multiple levels, which means that a component on the assembly BOM can be an assembly item itself. In that case, the Assembly BOM field on the assembly BOM line contains Yes.

Special requirements apply to items on assembly BOMs with regards to availability. For more information, see the "To see the availability of an item by its use in assembly BOMs" section in How to: View the Availability of Items.

There are two parts to creating an assembly BOM:

Setting up a new item
Defining the BOM structure of the assembly item.

Set up a new item. For more information, see How to: Register New Items.

Proceed to enter components or resources on the assembly BOM.
In the Item Card window for an assembly item, choose the Assembly action, and then choose the Assembly BOM action.
In the Assembly BOM window, fill in the fields as necessary. Choose a field to read a short description of the field or link to more information.

To view the components of an assembly item indented according to the BOM structure

From the Assembly BOM window, you can open a separate window that shows the components and any resources indented according to their BOM position under the assembly item.

Choose the icon, enter Items, and then choose the related link.
Open the card for an assembly item. (The Assembly BOM field in the Items window contains Yes.)
In the Item Card window, choose the Assembly action, and then choose the Assembly BOM action.
In the Assembly BOM window, choose the Show BOM action.

To replace the assembly item with its components on document lines

From any sales and purchase document that contains an assembly item, you can use a special function to replace the line for the assembly item with new lines for its components. This function is useful, for example, if you want to sell the components as a kit that represents the assembly item.

Caution: When you have used the Explode BOM function, you cannot easily undo it. You must delete the sales order lines representing the components and then reenter a sales order line for the assembly item.

The following procedure is based on a sales invoice. The same steps apply to other sales documents and to all purchase documents.

In the top right corner, choose the Search for Page or Report icon, enter Sales Invoices, and then choose the related link.
Open a sales invoice that contains a line for an assembly item.
Choose the line for an assembly item, and then Explode BOM line action.

All fields on the sales invoice line for the assembly item are cleared except for the Item and Description fields. Complete sales invoice lines are inserted for the components and possible resources that comprise the assembly item.

Note: The Explode BOM function is also available in the Assembly BOM window.

To calculate the standard cost of an assembly item

You calculate the unit cost of an assembly item by rolling up the unit cost of each component and resource in the item’s assembly BOM.

You can also calculate and update the standard cost for one or many items in the Standard Cost Worksheet window. For more information, see How to: Update Standard Costs.

The unit cost of an assembly BOM always equals the total of the unit costs of its components, including other assembly BOMs, and any resources.

In the top right corner, choose the Search for Page or Report icon, enter Items, and then choose the related link.
Open the card for an assembly item. (The Assembly BOM field in the Items window contains Yes.)
In the Item Card window, choose the Assembly action, and then choose the Assembly BOM action.
In the Assembly BOM window, choose the Calc. Standard Cost action.
Select one of the following options, and then choose the OK button.

Option	Description
Top Level	Calculates the assembly item's standard cost as the total cost of all purchased or assembled items on that assembly BOM regardless of any underlying assembly BOMs.
All Levels	Calculates the assembly's item standard cost as the sum of: 1) The calculated cost of all underlying assembly BOMs on the assembly BOM. 2) The cost of all purchased items on the assembly BOM.

The costs of the items that make up the assembly BOM are copied from the component item cards. The cost of each item is multiplied by the quantity, and the total cost is shown in the Unit Cost field on the item card.

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