INVESTIGATION OF CUTTING FORCES AND CHIP FORMATION CHARACTERISTICS IN ORTHOGONAL MACHINING OF ALUMINIUM.

Abstract

ABSTRACT In the last century, a large amount of research has been done to study and understand the various machining processes with a view to improving the processes for further economic (cost and productivity) gains. However, many aspects of the cutting processes and cutting performance remain to be fully understood in order to increase the cutting capability and optimize the cutting processes. Cutting is a process of extensive stresses and plastic deformations. The high compressive and frictional contact stresses on the tool face result in a substantial cutting force F. Cutting forces are the background for the evaluation of the necessary power in machining (choice of the electric motor). They are also used for dimensioning of machine tool components and the tool body. They influence the deformation of the work piece machined, its dimensional accuracy, chip formation and machining system stability. The aim of this work is to study the influence of feed rate, and tool rake angle and depth of cut on the main cutting force and chip morphology during a turning process, Aluminium alloy 6061 was used as workpiece material. In total,27 experiments were performed in order to measure the main cutting force (Fc). The experiments were performed with cutting depths of 0.5mm, 1.0mm and 1.5 and cutting speeds of 71, 90 and119 m/min, three different feed rates of 0.15, 0.20 and 0.25 mm/ rev. and three different rake angles 18o, 20o and 28o. During the experiment, the removed chips were collected and evaluated together with the main cutting forces. The experimental results showed that main cutting force has an increasing trend with the increasing of the feed rate between 0.05 to 0.7 mm rev. In contrast, the main cutting force has a decreasing trend as the rake angle increases from 0o to 200. There were indications that deformation occurred during the machining process, though the chip is generally continuous, chip length decreases as the cutting speed and feed rate increases. The experiment was done with the optimum of 12o rake angle for specimen.