This research work aimed to investigate the effect of shape factor, slurry layers and pouring temperature in precision investment casting. Three controllable factors of the precision investment casting process (namely: shape factor, slurry layers (mould thickness) and pouring temperature) were studied at three levels each by Taguchi's parametric approach and single-response optimization was conducted to identify the main factors controlling surface hardness , dimensional accuracy (Δd) and surface roughness (Ra). Castings were produced using aluminium, mild steel and stainless steel at recommended parameters through ceramic shell investment casting process. The micro structure analysis has been used to study the surface morphology. Cooling curve analysis was done to analyse the surface hardness data.