2. State of the art

The specifications that plastic injection molded parts have to meet are increasingly stringent, and cover a wide range of criteria. In particular, the control and reproducibility of the physical and dimensional characteristics of products are crucial, as is the limitation of rejects. These performances are directly linked to control of the complex interactions between internal variables (processing conditions) and external variables (materials with complex thermomechanical behavior, unsteady temperature, deformable tooling) in the process. Inevitable variations in these parameters, even of small amplitude, can lead to an unacceptable drift in final product properties. What's more, these fluctuations must be taken into account to further improve the reliability of the injection process. Unfortunately, conventional methods of controlling the injection process often reach their limits, making...