Turning is an art. On the one hand, it must be performed on state-of-the-art, highly precise, and expensive machines. On the other, this art requires a combination of superior craftsmanship, spatial awareness, and excellent programming skills.
Turning is almost always performed as batch production, not as flow production. Complex changeover processes must be performed for each batch, and all parameters must be reset. This increases the risk of errors, and therefore all production activities must be carried out under strict quality assurance guidelines and procedures.