What type of process is used for manufacturing plastic water bottles?

Blow molding is the correct process used for manufacturing plastic water bottles due to its efficiency in creating hollow objects from thermoplastic materials. The process involves inflating a heated plastic tube, called a parison, within a mold. As air is pumped into the parison, it expands to take the shape of the mold, forming a lightweight and uniform bottle. This technique is particularly advantageous for producing large quantities of bottles with consistent quality and dimensional accuracy.

Injection molding, while a common method for shaping plastics, typically produces solid items rather than hollow structures. Extrusion is used for continuous shapes like pipes or sheets, while compression molding is suited for creating solid products from thermosetting plastics. These methods do not accommodate the hollow nature and specific design needs of water bottles as effectively as blow molding does.