BOM anomalies

As a designer, the cBOM and eBOM are the two BOMs that you will interact with most frequently. If you need a refresher on these two types of BOMs, read the topic About Bill of Materials.

Generally speaking, every part and assembly file in your cBOM belongs to an item in Upchain. Therefore, for every part and assembly in your cBOM there is an associated item in your eBOM. In other words, your cBOM and eBOM are one to one.

There are exceptions to this:

• You can have a file in your cBOM that does not appear in your eBOM. These are called Phantom files and are used where you do not want an item to appear on your eBOM, such as:

  • Reference CAD
  • Individual parts within a purchased assembly that do not need to be managed in the eBOM separately.

• You can have items in your eBOM that do not appear in your cBOM, such as:

  • Items that do not have CAD, for example:

    • Fasteners that do not need to be modeled
    • Grease, paint, oil, etc.

Upchain helps you keep track of the differences between the cBOM and eBOM with the BOM anomaly window, sometimes referred to as the CAD Check in window or the BOM Wizard.