BOM Categories 

In the SAP System, you can use BOMs to represent different objects (such as materials, equipment, functional location BOMs, and documents) and to maintain object-specific data. Before you can create a BOM for the component parts of an object, the object must have a valid master record in your system.

The following graphic shows the objects for which you can create BOMs.

Material BOM: BOM with Reference to a Material

A bill of material that you create for a material is known as a material BOM in the SAP System.

To create a material master in the SAP System, you can use the following functions:

For this material, the system creates a material master immediately, so you can also create a BOM for it.

For this material, the system only generates a change document. This is why you cannot create a BOM for the material at first.
Only when you activate the scheduled material does the system create a material master record. Then you can create a BOM for it.

The material master record contains descriptive data such as the size, dimension, and weight of the material, and control data such as the material type and the industry sector. In addition to this user-maintained data, the material master record also contains data that is updated by the system, such as stocks.

Material BOMs are mainly used to represent the structure of products manufactured within your company. You can enter both materials and documents as components of this BOM. A document info record must exist in your SAP System for each document you enter.

This documentation uses the example of the material BOM to describe BOM functions.

Document Structure: BOM with Reference to a Document

A complex document may be made up of several documents, such as a program, technical drawings, papers, and photographs. These related information and documentation objects are grouped together as a unit using a document structure – a BOM for a document.

In effect, you create a BOM for a document info record. This "BOM" is known as a document structure.

You can find additional information on how to maintain document structures in the component CA – Document Management System. In the SAP-Library select Cross-Application Components ® Document Management System.

Equipment BOM: BOM with Reference to an Equipment

The system also allows you to maintain BOMs for equipment (technical objects for plant maintenance).

Equipment BOMs are used to describe the structure of equipment and to assign spare parts to equipment for maintenance purposes.

Since these BOMs are linked to equipment, they are known as equipment BOMs.

You can find additional information on how to maintain equipment BOMs in the component PM – Maintenance Bill of Material. In the SAP-Library select Logistics ® PM - Plant Maintenance ® Technical Objects ® PM - Maintenance Bill of Material.

Functional Location BOM: BOM with Reference to a Functional Location

Bills of material for functional locations group together the elements of a technical structure, such as the functional unit of an entire plant.

In the standard SAP System, a master record exists for each functional location. BOMs of this category are linked to these master records. This is why they are known as functional location BOMs. A functional location BOM can contain materials (PM structure elements and items relevant to plant maintenance) and documents.

You can find additional information on how to maintain functional location BOMs in the component PM – Maintenance Bill of Material. In the SAP-Library select Logistics ® PM - Plant Maintenance ® Technical Objects ® PM - Maintenance Bill of Material.

Order BOM: BOM with Reference to a Sales Order

You work with order BOMs when you specially tailor the make-to-order production of your products to the requirements of your customers. In order to meet the customer requirements, sales order specific modifications to various assemblies are often required. Furthermore, assemblies are often specially constructed for a particular sales order.

The order specific, modified or created BOMs are saved with reference to materials, sales orders, and sales order items. BOMs of this category are linked to sales orders, so they are known as sales order BOMs or order BOMs.

You can create order BOMs using the variant configuration as well as the BOM processing function.

The Orderbrowser is a navigation tool that you can use to get an overview of the multi-level BOMs of a sales order item and which you can use to navigate the various process and evaluation functions.

You can find additional information on how to maintain order BOMs under PP – Order BOMs. In the SAP-Library select Logistics ® PP – Production Planning and Control ® Basic Data ® Order BOMs.

Work Breakdown Structure BOM: BOM with Reference to a Production Lot

Production lots for finished and semi-finished products can be planned and manufactured using different BOMs. For example, a substituted component can trigger a targeted cost calculation and evaluation per production lot during the planning stage (before sales.

The number of a production lot is a WBS element from the Project System. You use this number to plan and manufacture the production lot for an assembly, and calculate the planned and actual costs for producing the assembly.

Because of the reference to a WBS element from the Project System, these BOMs are known as WBS BOMs.

You can find additional information on how to maintain WBS BOMs under PP – Planning Production Lots / Engineer-to-Order Production. In the SAP-Library select Logistics ® PP – Production Planning and Control ® Basic Data ® Planning Production Lots / Engineer-to-Order Production.