Which molding process is used to manufacture plastic water bottles?

• A. Injection Molding
• B. Extrusion Molding
• C. Compression Molding
• D. Blow Molding

Answer: (D)

Blow molding is used to create hollow plastic objects like water bottles by inflating a softened plastic parison inside a mold until it takes the shape of the bottle. This method is ideal for thin, uniform walls and a defined interior cavity, which is what bottles require. Other processes produce solid parts or continuous shapes rather than hollow containers, so they aren’t suited for bottles in the same way. In practice, bottle production often uses a two-step approach where a preform is made by injection molding and then blown into the final bottle shape, or uses extrusion blow molding to form the bottle directly.