Effect of Saw Dust Content on Slurry Rheology and Mechanical Properties of the Investment Casting Ceramic Shell

Abstract

The present investigation aims at determining the optimum quantity of saw dust that can be substituted to the secondary ceramic slurry for increasing the porosity of the destroyable investment casting ceramic shells without affecting its adequate strength. Further, both the slurry responses, namely viscosity, density, plate weight and pH, and shell responses, namely thickness, porosity, green strength and fired strength, determined from the saw dust based secondary ceramic slurry were optimized using Taguchi’s methodology. The input process parameters opted for the conduct of experiments were three different weight per cent of saw dust (3%, 5% and 7%), filler-to-binder ratio (1.5:1, 1.75:1 and 2:1) and slurry stirring time (18, 24 and 48 h). The optimum amount of saw dust that can be substituted in the secondary ceramic slurry for constructing the qualitative ceramic shells was found to be 5 wt%. The best combination of filler-to-binder ratio was established to be 2:1 for most of the responses except shell porosity. The range selected for slurry stirring time was found to be the insignificant process parameter influencing both slurry and shell responses.