Injection molding is a manufacturing process where plastic is forced into a mold cavity under pressure. A mold cavity is essentially a negative of the part being produced. The cavity is filled with plastic, and the plastic changes phase to a solid, resulting in a positive. Typically injection pressures range from 5000 to 20,000 psi. Because of the high pressures involved, the mold must be clamped shut during injection and cooling. Clamping forces are measured in tons.

Abbreviations for the Plastics Industry 
Plastics, Preproducts and Rubbers