Documentation: Bills-of-Material (BOM) and Item Master

A typical Bill-of-Material or BOM would consist of the following documentation components: item number, quantity used, UOM or unit of measure i.e. each, inches, ounces etc., internal P/N, revision (of part and BOM), description of part, reference designator, manufacturer name and manufacturer P/N. I have always liked having the prime manufacturer name and P/N for each respective part on a BOM because the BOM can sometimes serve as a multifunctional document for various groups and this aids in quick information location without having to go to other documents such as the AVL/AML for example.

You may also add items such as the assembly drawing to the BOM as a ‘reference’ item so that everything needed to assemble the particular part is listed on the BOM documentation.

The Item Master is what defines what the part is within the MRP/ERP system. Depending upon what MRP/ERP system you are using (if any at the moment), there will be a significant amount of attributes for each part item master. A few of the attributes that are important for this discussion are internal P/N, description, manufacturer name and P/N, UOM (unit of measure), item type and cost. Item type typically refers to whether the part is a ‘make’ or ‘buy’ part. All of this information is needed so that the purchasing person can order the correct part in a timely fashion. There is much more to this but having the basics above in place will usually yield you the right parts.

Here is a sample BOM format. View BOM Form Return to Documentation