Predicting the effect of machining parameters on turning characteristics of AA7075/TiB₂ in situ aluminum matrix composites using empirical relationships

Aluminum matrix composites (AMCs) are difficult to machine due to increased tool wear. AA7075/(0–12 wt%) TiB₂ in situ AMCs were prepared and turned in a modified conventional lathe using polycrystalline diamond cutting tool. A central composite rotatable design comprising of four process parameters and five levels was utilized to limit the actual experiments required for prediction. The turning parameters such as cutting speed, feed rate, depth of cut and TiB₂ particulate content were counted as variables for the experiments. Two empirical relationships were formed for the prediction of the outcome of variable parameters on cutting force and surface roughness. The cutting force showed a downward trend with an increase in cutting speed and TiB₂ content. The advancement in feed rate and depth of cut increased the requirement of cutting force. The predicted trends were correlated with the morphology of the tool rake face and the turned surface. The development of built-up edge increased the cutting force requirement and reduced the surface finish due to deposition on the newly turned surface.