Which method of crankshaft manufacturing is the least expensive?

Casting is considered the least expensive method of crankshaft manufacturing due to several factors inherent to the casting process. When crankshafts are cast, molten metal is poured into a mold, allowing for complex shapes to be formed without the need for extensive machining. This process requires less material waste compared to forging and machining, where excess material is typically cut away. The ability to produce large quantities of parts in a single operation also contributes to lower production costs in casting.

Furthermore, casting is particularly well-suited for producing components in bulk, which can further drive down costs due to economies of scale. The relatively simple equipment needed for casting compared to the more intricate machinery required for processes like machining or forging also helps keep costs lower.

In contrast, methods like forging and machining typically involve more labor and equipment expenses, as they require precise techniques to shape and finish the crankshaft, while extrusion is often used for different applications due to its process limitations. These aspects make casting the most economical choice for manufacturing crankshafts.