Final answer:
Vacuum-forming molds can be crafted from plaster, fiberglass, and aluminum, all of which have properties that are suitable for the vacuum-forming process, allowing the creation of detailed, durable objects.
Step-by-step explanation:
Three materials that vacuum-forming molds can be made from are plaster, fiberglass, and aluminum. These materials are chosen for their ability to withstand the pressures and temperatures associated with the vacuum-forming process. Aluminum is widely used for professional-grade molds due to its durability and thermal conductivity. Plaster can be used for prototypes or short runs because it's inexpensive but less durable. Fiberglass is often utilized when complex shapes or fine details are required in the final product. Vacuum-forming is different from other plastic manufacturing processes such as injection molding, where molten polymer is injected into a mold, or extrusion, where the material is pushed through a die to create objects with a fixed cross-sectional profile.