Effects of Casting Parameters on Shape Replication and Surface Roughness of LM6 Aluminium Alloy Cast Using Lost Foam Process

Abstract

In this paper, an experimental investigation on shape replication and surface roughness of Al-12 wt% Si alloy casting produced by lost foam casting process was conducted. 5-step shape patterns incorporated with top and bottom gates were used. Four top gating systems with different pouring cup configurations namely single-middle, single-side, double and single-wide and a simple bottom gate design were investigated to appropriate filling to produces sound casting. Three sand vibration times of 1, 2 and 3 min were used for the moulding process. Molten metal was poured at five different temperatures of 660, 680, 700, 720 and 740 °C. Shape replication and surface roughness of the cast samples were analysed visually and by roughness tester, respectively. The results showed that pouring cup design has a significant effect on the replication and surface integrity of the castings. It was also found that single top-wide pouring cup as well as lower vibration time and higher pouring temperature provided castings with better shape replication and smoother surface finish with a surface roughness of 19–20 µm compared to 25–31 µm for castings produced with other cup configurations.