Many engineering thermoplastic materials require high mold operating temperatures. Commonly this is achieved by using oil temperature control units. This presentation will discuss a new technology to control the mold temperature up to 400degF by using water. The presentation will outline all the benefits the processor will have when considering water as heat transfer medium for high heat application. As you know, working with high technology plastic material, the mold temperature can be 360 °F and higher. Water is up to 8 times better in heat transfer than oil. Water has a high specific heat capacity, high coefficient of thermal conductivity, and a high heat transfer coefficient. There is no danger when leakage occurs, disposal is not a problem, no carbon development, dangerous gases are not generated, and water is not combustible. It is easy to change the mold and it is cleaner and cheaper.