Injection molding is used in more ways that you might think. Common household products like toothbrush handles are created using plastic injection molding, as well as medical supplies, spools, and musical instruments. It is the most common plastic molding method used globally. The first plastic injection molding machine was patented in the late 1800s by John Wesley Hyatt and his brother. About one century later, plastic production processes replaced steel production processes as the most widely used. As a result, injection molding took off and today, this type of production is vital to the production of most products.