Evaluation of the Effect of Starch as Binder in Sand Casting of Aluminium

This study focuses on evaluating the effectiveness of cassava starch as an organic binder in sand preparation for aluminium casting, emphasising its influence on key mould properties, moisture content and green compressive strength and overall casting quality. Silica sand mixtures were prepared with cassava starch at 7.5%, 10%, and 12.5% by weight, molded into cylindrical samples, and tested for moisture content, green compressive strength, hardness, and compressive strength. The results revealed that the moisture content of the samples decreased from 6.3% in the control to 3.9% at 12.5% starch, indicating improved moisture regulation with starch addition. The green compressive strength peaked at 30.6 kN/m² at 10% starch, while hardness reached 12.4 HV and compressive strength attained 35.2 MPa at the same starch level, outperforming the control sample (27 MPa) in mould stability and casting performance. Beyond 10% starch, a slight decline in mechanical strength was observed, attributed to excess binder content leading to reduced compaction and increased gas evolution. The study concludes that cassava starch at approximately 10 wt% provides the optimal balance between mould integrity, strength, and environmental sustainability, establishing it as an effective, eco-friendly binder for improved aluminium casting quality.