This book closes a fundamental gap in the field of mold design. The use of injection molding coatings extends the technical possibilities in the field of plastics production, such as the achievable flow path length, the use of abrasive and corrosive plastics, and the achievable tool life. This possibility of functionalization has so far been somewhat neglected due to a lack of available information on the state of the art and possible applications. This book therefore brings together the available knowledge of various experts in a way that is understandable for engineering students and tool and mold makers. The book covers the individual steps of coating technologies. First, the steel materials that are mainly used for the construction of tools in plastics processing are presented. This is followed by the current status of the various coating technologies. The existing coating technologies are presented and characterized with regard to their suitability for use in tool technology in the plastics processing environment. The third part deals with the characterization of the deposited coatings. On the one hand, the focus is on the characterization of the actual coating, such as chemical composition, coating layout and coating thickness. Secondly, the measurement methods for determining the functional properties of the deposited coatings, such as hardness and wear resistance, thermal properties, thermal conductivity and tribological properties, are presented. Finally, the use of appropriate coatings is illustrated using practical examples from plastics technology.