How to improve molten metal yield of aluminum gravity die castings?

摘要

The objective of this paper is to share the practical knowledge gained in improving the molten metal yield of aluminum gravity die castings. One of the major draw backs of gravity die castings is poor yield. For example, to produce 1 kg of salable castings, we have to pour at least two kilos of molten metal. In general, the yield will be about 45%, which makes the process uneconomical. Volume increase by re-melting causes higher melting loss due to oxidation & loss of magnesium by evaporation, which is to be compensated. This increases the cost. Using simulation technology during die design stage, and applying thermo dynamic principles along with practical knowledge, the quantity of molten metal poured can be reduced considerably. In this paper the methodology was explained in detail. Matrix diagrams and some practical methods were explained for eliminating certain "die design constraints". Based on actual foundry shop floor work, four real case studies of actual yield improvement projects were presented.