A Study of Wave Formation in Shot Sleeve of a Die Casting Machine

The objective of this study was to find the optimum process variables for minimizing the amount of air entrapped within the shot sleeve during the slow shot phase of the injection process. To achieve this objective, the relations between process variables (e.g., plunger speed/acceleration, initial filling percentage, sleeve diameter, etc.) and the wave formation within the shot sleeve of a die casting machine have to be determined. For this purpose, a mathematical model has been developed to study the transient wave formation in shot sleeve. The model based on the theory of waves of finite amplitude can predict the critical plunger speed and the profile of wave front, which in turn affect the degree of air entrapment. The optimum plunger speeds for minimum air entrapment are thus determined based on the predicted profile of wave front. Good agreement with the results from water analogue experiments is found.