The questioner is correct that “parts” made from castings are the easiest way to determine whether you are classifying a “part” compared to a “component.” However, the definition of “part” also extends to other types of manufacturing processes where the commodity being created is a single unassembled element and, importantly, is not normally subject to disassembly without the destruction or the impairment of design use. These phrases from the definition of “part” help to refine the scope of what is considered a “part.”
Must be a single element. For example, any commodity that includes assembly instructions or blue prints for connecting more than one single element, would take the commodity in question outside the scope of the definition of “part.” In this example, the commodity would be considered an assembly, a term which under the EAR, is also referred to as a “component.”
Must not normally be subject to disassembly without the destruction or the impairment of the commodity’s design use. Manufacturing methods where a “part” is made by welding or diffusion bonding that permanently combines together elements to make a single unassembled element would meet this criterion from the definition because any disassembly would clearly destroy the commodity or at a minimum impair its design use.