Examination of Variable Tilting Speed on Flow Behaviour during Ladle Pouring in Die Casting using SPH Simulation

  • Itakura, Fuga (Daido University)
  • Yamada, Toru (Daido University)
  • Maeda, Yasuhiro (Daido University)
  • Hasuno, Akihiro (Ryobi Limited)
  • Mochida, Yasushi (Ryobi Limited)

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Disturbance of the molten metal flow during ladle pouring before plunger advancing in the aluminium alloy die casting process can cause the entrapment defects of air and oxide film.[1][2] Slow pouring to control the turbulence of the flow front reduces productivity due to increased cycle time. Further, the risk of cold flakes formation increases caused by large temperature drops in accordance with long cycle time.[3] On the other hand, rapid pouring is desired to improve productivity, but the risk of air entrapment increases. Therefore, quick and quiet pouring is desired in the ladle pouring process. In the present study, we focused on variable tilting speed as a method to achieve good ladle pouring. The effects of variable ladle tilting speed and switching time on the wave behavior of molten metal are investigated in visualization experiments and simulations. The flow behaviours in ladle pouring are simulated using "COLMINA CAE", which is the casting analysis software by particle-based SPH method.[4] Furthermore, the plunger advancing process was also examined. From the simulation results, the variable tilting speed from fast to low can suppress the rise of the maximum wave height of molten aluminium alloy. However, the pouring completion time is longer. Further, the falling position of molten metal poured from the ladle varied with changing tilting speed. And then, the wave height was influenced not only by ladle pouring but also by the plunger advancing process. These trends of wave behaviour obtained in the simulation were similar to that of the actual phenomenon. Therefore, the present simulation method can accurately estimate the ladle pouring process and plunger advancing process. So, casting CAE is an effective tool for exploring die casting conditions.