Since there is no mold that comes as an obstacle between a design and parts in AM, the conversion of a design into parts does not depend on the mold. The maximum production volume is no longer limited by the quality of a mold. In AM, producing a few parts is not the underutilization of an AM system, while in a mold-based system, producing a few parts can mean the underutilization of the system. The conversion in AM has the flexibility to choose serial production for a low volume and either serial or non-serial production for a high volume, which is not available in mold-based processes. Machining has the advantage of selecting either serial or non-serial type to change the volume, but machining depends on tools and fixtures, which does not give the same flexibility as AM does.