Oblique Gate Direction During Centrifugal Casting in Artificial Lumbar Disc Model of CP-Ti

Oblique gate direction in different angles was hardly applied in centrifugal casting. The purpose of this research was to determine the effects of oblique gate direction in centrifugal casting on density, porosity, roughness, and microstructures in the artificial lumbar disc model. The angles of the oblique gate were ranged from 30º to 150º toward to the runner. The sharp turn of the gate would cause retardations and losses friction that decreased the pressure in molten metal. This process caused the porosity and the surface roughness decreased while the density increased. The product in which the oblique gate direction was the same with the mold rotation was better than the one in the opposite direction. The tangential forces would increase the forces acting on molten metal when entered the mold with the oblique gate direction that same with the mold rotation. Gate with the θ of 90º was the most widely used, but the product was better to use the gate with the θ of 60º than the product with the θ of 90º. Hence, to obtain an artificial lumbar disc model with less porosity, high density, and smooth surface, the oblique gate of 60º should be applied.