Holes quality investigations and comparative analysis in CNC-drilling of AISI-4340 AISI-1055 steels

摘要

This article focuses on the investigations of holes quality and comparative analysis in terms of surface roughness and diameter error in CNC-drilling of AISI-4340 and AISI-1055 steels under dry as well as wet cutting condition.All experiments were conducted with high speed steel(HSS)twist-drill of diameter 7.78mm viaTaguchi method.For the experiments,L9 Taguchi orthogonal array design was selected.The statistical analysis methods such as S/N ratio of Taguchi method and ANOVA were employed to optimize the machining parameters and to investigate the influence of machining parameters on the average surface-roughness(Ra)and diameter error(DE).All experimental data of Ra and DE were used to develop second-order regression-models.These second-order regression-models could be utilized to predict the responses in CNC-drilling of both steels with a very small error.Finally,machining performance comparison between AISI-4340 and AISI-1055 steels on the basis of surface roughness and diameter error obtained were carried out.Results of this study show that the machinability of AISI-4340 steel is better than the machinability of AISI-1055 steel in terms of surface roughness and diameter error obtained in CNC-drilling.And the surface quality of holes was better with wet-cutting conditions in CNC-drilling of both the materials.