Simulation of High Pressure Die Casting (HPDC) via STAR-Cast
STAR-Cast’s multiphase approach, the HRIC algorithm for interface capturing, the advanced meshing techniques and the STAR-Cast power session are the key features in rigorous simulation of HPDC processes. The predominant process input parameter is the shot curve, which determines melt flow from the filling chamber via controlled piston movement into the mold insert, and thus the compression and outflow of air.
Left: Coupled mold filling and solidification simulation for HPDC relies on STAR-Cast’s multiphase approach and a moving mesh technology for the plunger movement in the filling chamber.
Right: Mold filling conditions are well-defined by the shot curve as part of the input parameter set.
All input parameters can be defined via the STAR-Cast graphical user interface for HPDC-processes: the cooling and heating system conditions of the mold insert, die cycle warm-up, shot curve, air outlet conditions and casting temperature. STAR-Cast provides shot curve definition including a switch point from velocity control to pressure control. In particular, HPDC processes under reduced pressure in the mold cavity can be simulated by applying appropriate pressure outlet boundary conditions. STAR-Cast’s multiphase approach enables precise modelling of mold filling, air entrapment and misrun formation. A special application is the simulation of die venting by means of venting blocks, acting as outflow valves for liquid metal through misrun formation in the venting block.
Meshing: Unstructured polyhedral mesh including thin layer at material interfaces for good prediction of thin section fill and precise calculation of high gradients.
Initial temperatures in die and shot sleeve: Calculated initial temperature distribution via die cycle warm-up.