Analysis of the numerical simulation of the filling system used in production of aluminum pistons

Permanent-molding casting of aluminum-based pistons is affected by defects that cause rejection in quality-check control. Current scientific and technical literature plus in-situ experiences have allowed the identification of the causes of such problems. One of these causes is a direct consequence of a poor feeding system, which produces excessive velocities and critical conditions that generate turbulence and detachment of the thin film oxide lining of the feeding system, as well as bubble trapping. In this work, by means of numerical simulation, different feeding systems currently in use were studied (the analysis does not account for bubble trapping.) Modifications are suggested based on the analysis of these results. These modifications have a direct impact in the geometry of the feeding system, avoiding stagnation points as well as excessive velocities, giving as a result important reductions in the rejection of defective pistons.