Filling velocities and defects of plate shaped diecastings.

The casting defects are reduced by increasing the molten metal velocity near the defects. When the linear runner, where flowout volume through the lower runner gate was greater than the volume through the upper one, was used, the molten metal unequally filled up the cavity and the molten metal velocity suddenly decreased at a final filling portion. Therefore, the casting defects frequently occurred at the final filling portion. On the other hand, when the stair shaped runner was used, the molten metal equally filled up the cavity without a turbulent flow, and the molten metal velocity did not decrease at the final filling portion. Therefore, the molten metal filled up the cavity with inconsiderable casting defects in a short time.