Study on Effect of Tool Overhang on Machining Characteristics of Al 7075-T6 in Orthogonal Turning Process

Abstract

In the present experimental study, the effect of turning tool overhang on the chip morphology and vibrations during orthogonal turning has been investigated. Orthogonal cutting (turning) setup was developed to ensure the cutting process happens in a 2-dimesional plane. Orthogonal cutting was realized by turning a circular tube with geometry of 33.88 mm external diameter and 3.5 mm wall thickness (7075-T6 Alloy). High speed steel (HSS) rod with a square cross-section (1⁄2 x 1⁄2 square inch) was used to fabricate the orthogonal turning tool with a geometry of 15 ̊ back rake angle and 9 ̊ clearance angle. The cutting experiments were conducted for different tool overhang lengths (2cm, 3cm, 4cm, 5cm & 6cm) by keeping constant cutting speed (25 m/min) and feed (0.15mm/rev). The vibrational characteristics were measured using accelerometer and Ni-DAQ card. The morphology and microstructure of the chips collected during cutting were studied under optical microscope using metallographic procedures. It was found that for increasing overhang length of cutting tool the chips serrations was found increasing. The frequency of cutting tool and amplitude of vibration was found increasing with increasing tool overhang length.