Everyday product molds are tools that shape materials through specific cavities. Essentially, they are negative form conversion systems, physical interfaces that constrain flowing or malleable materials into a predetermined shape. From plastic basins to metal tableware, the regular shapes of most everyday items originate from the molding control of molds.
The shaping of objects by molds begins with a topological locking mechanism. When molten plastic is injected into the mold cavity, the material does not simply fill the space, but undergoes directional reorganization of molecular chains under a pressure gradient. The cooling system of the injection mold causes the material to solidify along a specific thermodynamic path, forming a predetermined structural topology. This locking not only fixes the shape but also determines the distribution of internal stress at the microscopic level. For example, the difference in cooling shrinkage at the thickness of a plastic water cup's wall is actually controlled by pre-calculated water channel layout in the mold.