A multiple bill of material (BOM) is a type of BOM that allows for different combinations ofcomponents or raw materials for the same assembly or subassembly. The reason for different combinations of components in a multiple BOM could be the manufacturing date or the lot size. The manufacturing date determines the validity period of the BOM, which means that different BOMs can be valid for different time intervals. For example, a BOM can be changed due to a design modification or a change in the availability of components.
The lot size determines the quantity-dependent explosion of the BOM, which means that different BOMs can be used for different production quantities. For example, a BOM can be optimized for different batch sizes or different production methods. References: Multiple BOM, BOM Explosion