Experimental verification of numerical predictions for the optimum plunger speed in the slow phase of a high-pressure die casting machine

摘要

An experimental study of the optimum maximum plunger speed in the slow phase of a high-pressure die casting machine with horizontal cold chamber is presented. A special apparatus that uses a photoelectric sensor to determine the instant at which the working fluid reaches the runner was developed and installed in the injection chamber. The measured volumes of air remaining in the chamber at this instant for various maximum plunger speeds were compared with those predicted by a three-dimensional numerical model based on a finite element formulation and the volume of fluid method for treating the free surface. Very good agreement was found between experimental and numerical results, except for maximum plunger speeds higher than the optimal, for which very complex fluid flow phenomena (that would require a more detailed numerical analysis of the air entrapment mechanisms) tend to be produced. The optimum maximum plunger speed at which the measured volume of trapped air is minimum was found to be very close to that predicted numerically.