The Effect of Stucco Sand Size on the Shell Mould Permeability and Modulus of Rupture (MOR)

Abstract

Investment casting or known as lost wax casting is a technique that offers broad advantages in providing a near-net shaped product and significant to mass production rates. The unique mould making method of IC, able this technique to fulfil complex geometrical shape application. The ceramic shell mould is the key that implies the quality of the product. Permeability and modulus of rupture (MOR) are two dominant properties to be considered. Permeability is important during casting of molten metal to avoid defects or cracks caused by the increased pressure inside due to the blockage of trapped gases to pass throughout the mould. MOR is defined as the strength of the mould to its ability to withstand the stress generated during de-waxing and casting of molten materials. Stucco size is one of the significant factors to affect these subsequent mould properties. In relation to that, this research was conducted to analyse the effect of stucco matrix towards the mould properties. The stucco sand was aluminosilicates formed in two sizes; mesh 50 and mesh 30. The matrix comprises of three types; mesh 50 stuccoed shell mould, mesh 30 stuccoed shell mould, and conjugation of mesh 50 and 30 stuccoed shell mould. The results revealed that the highest permeability of 1.15681 x 10-7 m2 was obtained from sample B (mesh 50 stuccoed matrix), and peak MOR value of 10.9 MPa was on sample C (mesh 50-30 stuccoed matrix).