Which process involves heating materials to provide a shape by cooling?

The process of thermoforming is specifically designed to shape materials, typically plastics, by heating them until they become pliable and then forming them into specific shapes as they cool. During thermoforming, a sheet of plastic is heated, often to a point where it becomes soft enough to be deformed. Once it is shaped—commonly over a mold or as part of a desired product—it is allowed to cool, at which point it retains the new shape due to the nature of thermoplastics.

This method is particularly useful for creating parts with relatively simple geometries and is popular in industries such as packaging and product design. The crucial aspect of this process is the ability to create a shape through the combination of heating and cooling, which distinguishes it from the alternatives that involve different manipulation methods, such as cutting or machining, rather than shape-forming through heat.