What manufacturing process involves injecting melted resin into a hollow mold?

The correct choice is based on the fundamental principles of manufacturing processes. Injection molding is characterized by the method of heating resin to a molten state and then injecting this liquid material into a precisely shaped mold under high pressure. This technique allows for the creation of complex shapes and high production efficiency, making it suitable for manufacturing a variety of products, including plastic parts.

In injection molding, once the resin cools and solidifies inside the mold, it takes the form of the mold cavity, which can then be ejected. This process is widely used in industries such as automotive, consumer goods, and electronics due to its ability to produce detailed designs with high repeatability.

Other options present different processes: blow molding involves forming hollow objects by inflating a softened material against the sides of the mold, which differs from the direct injection method of resin. 3D printing utilizes additive manufacturing techniques to layer materials to create objects rather than injecting melted material into a mold. Extrusion molding involves forcing material through a die to create continuous shapes, rather than using a two-part mold system like in injection molding.