Application of Box-Behnken design for the optimisation of process parameters in dry drilling operation

Drilling is one of the important fundamental metal cutting processes used in manufacturing industry for making hole in a specimen. This paper is carried out to find optimal parameter settings in dry drilling of mild steel specimen in a radial drilling machine using Box‐Behnken design (BBD). The effect of the input process parameters such as speed, feed and drill diameter and their interactions on responses such as cutting force and torque are studied using second‐order response surface modelling (RSM). The model analyses are done based on analysis of variance (ANOVA) and F‐test, which indicate that the feed rate and interaction of feed and drill diameter is most significant on cutting force while for torque, interaction of speed and drill diameter is also significant in addition to feed rate and interaction of feed and drill diameter. Predicted value obtained using model equations are in good agreement with the experimental value of force and torque. Finally, the optimal parameter settings for force (speed 150 rpm, feed 0.29 mm/rev and drill diameter 14 mm) and torque (speed 150 rpm, feed 0.19, drill diameter 12 mm) are identified from the response plots.