17. Injection Molding and Its Variants

The most versatile and productive part shaping method for plastics by far is injection molding; it is also the oldest and, perhaps, the most developed. It is conceptually a very simple process: molten plastic, well above the glass-transition temperature, is injected into a cooled, mold cavity formed by a two-sided mold, the shape of which determines the final nominal part shape, including its thickness. The part is ejected on cooling.