To describe the shape and location of free surfaces in the mold filling simulation,
parameters including volume filled ratio, surface dimensionless distance, and surface filled ratio for
the DFDM (Direct Finite Difference Method) elements were proposed. A model of mold filling
process was established, considering the mass, momentum and heat transfer in the vicinity of free
surface. It had been applied to an experimental Al casting. In-situ observation and record of actual
mold filling process of the casting with special X-ray apparatus were carried out, and were used to
validate the simulation results. The validation showed that the model could predict the mold filling
process well. It was found that back pressure of gas in the mould cavity had minor effect on change
of liquid flow when using pressurized feeding system and sand mould with good air permeability.
Characteristics of the mold filling simulation for a variothermal injection molding process with highly filled thermoplastics
