Partial quantities of a BOM item may be installed at different points. Sub-items are used to describe the different installation points of these partial quantities.
In Customizing for bills of material, under Define modification parameters, you can define whether the old change state of a sub-item is retained after you change the sub-item.
If at least one values of the sub-item is changed with changed effectivity parameters, the system creates a new item record for the new change state.
Sub-items have no operational function in the BOM. They are not copied to the production order. However, you can use sub-items to help you create programs for your company (for example, automatic assembly programs).
In the production of printed circuit boards, the resistors of a printed circuit are installed in different positions. Information on the installation point, precise coordinates, installation method, and instructions for the automatic assembly machines is stored as independent programs.