This work aims to develop flow and thermal control methods for the high pressure die casting (HPDC) of very thin-walled aluminium components where thicknesses are predominantly less than 1 mm. One specific aim includes developing advanced modelling capability using CFD software to predict the complex structure of the metal flow in the die and the casting solidification. The modelling based on FLOW-3D started initially with a fluidity die study to establish several key parameters in HPDC modelling through experimental validation. A new test casting geometry has been designed in the form of a shallow tray with other features such as changes in curvature, fins and bosses. The casting thickness can be made variable in the die. The experimental work was conducted on a 250-tonne HPDC machine. Initial models of molten metal flow in the die cavity based on a runner design for casting thicknesses between 1.5 mm and 1 mm are presented. The detailed model required a very large mesh of very small elements, and more accurate physical parameters which may not have been previously available.