Plastic injection molding has been widely used in the past and is a dominant forming approach today. Injection molding is one of the most important processes in the plastic manufacturing industry. More than one-third of all plastic materials are injection molded, and the mold is one of the main components in the injection molding process. The aim of this engineering book is to show detailed steps on how to design a complete mold and use of the simulation software to analyze the material flow and identify manufacturing defects in the product. The cost of the mold is high and any process that is not optimized renders heavy overheads during its development cycle and production. So designing the mold which ensures the best suitability for the features on the component with the smooth flow of molten plastic is a very important part of the development process. To better understand plastic injection molding and the effects of the core process parameters on the process, performances has been studied using the state-of-the-art computer-aided engineering (CAE) design tool, Moldflow analysis software.