Characterization of chip formation during machining 1045 steel

A deep understanding of the generation and characterization of chip formation can result for practical advices of chip type controlling in engineering applications. The chip formation is divided into the continuous chip and the serrated one in this study. The characterization of the continuous chip formation is expressed as the chip deformation and that of the serrated chip formation is expressed as the frequency of serration, the degree of segmentation, and the deformation of serrated chip. The chips of 1045 steel under different cutting speeds (100–3,600?m/min) are collected during machining. After inlay and polishing of the collected chips, the chip morphology is observed with VHX-600 ESO digital microscope. It is found that at the cutting speeds of 100–400?m/min, the chip type is continuous, at the cutting speeds of 600–2,200?m/min the chip type is serrated, and at the cutting speeds of 2,500–3,600?m/min the chip type is segmented. The quantitative relations between the characterization parameters of chip formation and the cutting speed are obtained. The chip deformation increases with the cutting speed, and the influence of the cutting speed on the shear strain rate is more sensitive than that on the shear strain during the continuous chip formation. All the characterization parameters including the shear strain rate, the frequency of serration, the degree of segmentation, and the shear strain increase with the cutting speed during the serrated chip formation. The sensitivity of influence of the cutting speed on these parameters is in the following: the shear strain rate, the degree of segmentation, the frequency of serration, and the shear strain.