The Bill of Materials (BOM) describes the specific components of a product and is a pivotal element in SAP. While the BOM is used in many modules and is by itself a time-saver, it can become tedious to maintain one BOM per material variant when there is a huge number of them. Read on to find out how the variant BOM can overcome this problem by constituting a single entry point for the maintenance and overview of all variants of a material.
In order to better understand the variant BOM concept, let’s begin with a simple business scenario at a fictional bike company, which we will call Super Awesome Bikes (SAB). The company makes three bike models:
- The Mountaineer, a mountain bike;
- The Wayfarer, a road bike;
- The Slowpoke, a kid’s bike.
Since those three models are variants of a bike, they inevitably have identical components, like the rubber grips, wheel spokes or colors of paint. However, they also have parts which are specific to the bike model, like the air suspension which would only be found on the mountain bike, for example.
Now let’s suppose that there is one BOM for each bike model and that one of the common components is to be discontinued. The BOMs now have to be changed, and that means individually going in each model’s BOM to replace the discontinued part with the new one. As mentioned previously, this is a really simple business scenario at SAB, but in reality companies usually have a huge number of material variants for which the bills of materials have to be up to date.
This is where BOM maintenance and viewing potentially becomes tedious and error-prone. For example, there could be forgotten material BOMs still using a common component that is soon-to be discontinued, therefore preventing its discontinuation from the materials management side of SAP until removal from remaining BOMs. Returning to the SAB scenario, potential errors and longer BOM maintenance times could be avoided by using one variant BOM for all three bike models instead of three regular BOMs.
The reason why the variant BOM is a time-saver is that as mentioned previously, it constitutes a single entry point for the maintenance of all variants of a product. It is most useful when producing several similar product variants which share a lot of common components. Therefore, a variant BOM is assigned to many materials and describes the components being used in all of them. Also, the variant BOM’s summarized view gives a visual representation of the usage of the components by each material variant, displaying a table with the components as lines and the material variants as columns.
NOTE: In SAP, you will see the term BOM group rather than variant BOM, like in the picture above. However, there is another construct in SAP which is called the group BOM and which is something different than the BOM group we are exploring today. Since BOM group and group BOM are easily confused and have different applications, I personally prefer to use the term variant BOM when talking about BOM groups.
Creating the Variant BOM
For more detailed steps in an example, scroll down to the video guide below.
In order to make a variant BOM in SAP, you can either start with a new BOM (transaction CS01) or an existing one (transaction CS02) for your first variant. The important thing to do regardless is to go to the BOM header and set a BOM group name to it. This is what identifies the previously normal BOM as a group, which will allow quick access to it via transaction CS05 in order to view all its components and variants.
Now that the group exists with one variant in it, let’s add another variant to it. This is done by creating a new BOM as a variant of the one we previously created/modified. Select the common components to be used and copy them, then add any specific components and save.
Viewing/changing the variant BOM
The freshly created group can be accessed by using transaction CS05 with the relevant selection parameters. Once accessed, the variant BOM is shown in a summarized view, again with the components as lines and the variants as columns. In order to know what the variant numbers correspond to, simply click the variants button. Another drilldown can also be done from the subsequent screen by selecting the variant and clicking the items button. This will show the individual BOM for that specific material variant, with all its specific BOM components. Maintenance is similar to any other BOM, with line additions and deletions performed in the same way. The difference here is that when a new line is added, the columns corresponding to the variants using the component have to be ticked to indicate where it is used.
For a detailed hands-on example of variant BOM setup in SAP, please view the following video.