# BOM Management

## Introduction

A Bill of Materials (BOM) is a structured list of parts and sub-assemblies that create a product. With the help of BOM Management, product structures can be represented and individual items (parts, sub-assemblies, etc.) related to each other. The product structure, consisting of sub-assemblies and individual parts, is built up hierarchically. The product, as top-level element in a BOM, is called the BOM head.

The following illustration shows an example of a BOM for a product made up of sub-assemblies and individual parts.

The products, sub-assemblies and parts in BOM Management are know as "items" and are created and managed in the Item Management module. Only items that have already been created in Item Management can be brought up in BOM Management.

BOM Management also supports multiple variants. When a variant of a product is created, the variable positions in the BOM are occupied by placeholders. In Variant Management, the variant placeholders are replaced by actual items, creating an order-specific BOM based on the Item Management BOM.

The following sections describe the BOM philosophy in more detail and explains the most important terms.

### Design BOM: At the Beginning

When new products are developed, individual parts are designed, put together into subassemblies, and finally assembled to form the product. All the parts of the product, that is being developed, are listed in design BOMs which are stored as BOMs by the BOM Management. The BOM contains not only individual parts, but also sub-assemblies which in turn have their own BOMs. This structure is based on the Modular Design principle.

A simple BOM also contains additional information known as position information.

Examples of position information are:

- Mandatory part
- Optional part

or date entries like:

- Valid From
- Valid Until
- Select Current or position-specific data from the master element

This position information can be expanded to include Context dependencies.

### Product Structure Represented as a BOM Set

The combination of individual parts, that are part of sub-assemblies which in turn are part of products and all with their respective BOMs, are known as the BOM set of a product. The combination of BOMs also reflects the structure of the product. Such structural context is represented in the Structure BOM.

### Modular Design Principle

The BOM of a given item contains only those items that form a part of it directly. In the BOM of a product there is no initial differentiation between individual parts and sub-assemblies. As soon as it is used in a product, the BOM head of a sub-assembly in the modular design model is simply an item.

A separate BOM is created for each sub-assembly, so that a sub-assembly is both, an item which can be used in other BOMs and a BOM header (the item ID of the sub-assembly) with its own parts and sub-assemblies.

All products, sub-assemblies and individual parts are managed as items.

### BOM Structure

In Agile e6 the product structure can be displayed as a structure explosion, either graphically or in table form.

In this display, the product BOM is linked hierarchically with the BOMs of all containing sub-assemblies. The structure of complex products can be completely expanded in this way. The resulting multi-level hierarchy can be shown graphically or in table form.

The product structure is the logical link between product development and production, this is because production organization is a function of product structure. The manufacture of individual parts, assemblies and final assemblies of a product are all strongly linked to the structure of the product.

### Quantity Overview

Planning production requires knowing the quantities of the parts and sub-assemblies required. The quantity overview is designed to meet this demand. It lists all the required items and their quantity for a product. The required individual parts are listed, independent of if they occur in one or another sub-assembly.

### BOM Comparison

In the development and production of product variants, in which many parts are identical or in environments where parts or sub-assemblies are used in different products, it is important to be able to compare BOMs. The BOM comparison feature evaluates existing BOMs and makes the commonalities and difference between the associated products clear. On the other hand it is important to know where a given item is used. The where-used feature shows which assemblies and products contain a given item.

### Where-Used

Where-used is another function for analyzing the information in the BOMs. The single-level where-used function displays all assemblies and products in which a given item is used directly, whereas, the multi-level where-used displays all levels up to the final product.