PENGARUH SUDUT MATA PAHAT TERHADAP HASIL PEMBUBUTAN PERMUKAAN BAJA ST 70

Manufacturing factories continue to grow along with advances in science and technology, this is evidenced by the increase in production output. An increase in production output needs to be equated with an increase in production quality. This study aims to determine the effect of variations in the main angle (Kr) on the cylindrical surface of the workpiece, and to determine the effect of variations in feeding (feed rate) on the cylindrical surface of the workpiece. The research method used is the testing method, this study uses ST 70 steel with a diameter of (d) 32mm, and the type of chisel used is a High Speed Steel (HSS) chisel with variations in the angle of cut (Kr) 80?, 85? and 90? and variations in feeding motion 0.082 mm/rev, 0.120 mm/rev and 0.164 mm/rev. This research was conducted at the Laboratory of Mechanical Tecnology of the Department of Mechanical Engineering, Universitas Tadulako.
The results of this study found that The greater the main cutting angle (Kr), the more it affects the cylindrical value, this is caused by the friction between the chisel and the workpiece that occurs during the turning process. In this study, the highest cylindricality was obtained by 85 µm on the tool with an angle (Kr) = 90?, this is because the friction that occurs at the angle (Kr) = 90? is greater than the friction that occurs at the angle (Kr) = 85? and 80? which has a cylindrical level of 10 µm. The larger the feed motion (f), the smaller the cylindrical value but must be included with a small angle (Kr), because the friction caused by the small tool angle does not really affect the length of time the feed motion (f) is caused. by friction of the tool with the specimen. With feeding motion (f) = 0.164 mm/rev at angles (Kr) = 80? and 85?, the cylindrical level is 10 µm.