Application of Box–Behnken Experimental Design with Response Surface Methodology for Prediction of Surface Roughness in Boring Turning of Carbon Steel Grade S45C

Abstract

Nowadays, carbon steel grade S45C is now widely used in industry which is brought through the workpiece turning process. And it is necessary to know how to determine the appropriate turning factor. The aim of this research was to apply the Box–Behnken experimental design with response surface methodology for predicting the surface roughness in the boring of carbon steel grade S45C. The factors used in the experiment consisted of the speed of 800 – 1,700 rpm, feed rate of 0.06 – 0.10 mm/rev, depth of cut of 0.25 – 0.35 mm, and the overhang of 25 – 45 mm. The experiment showed that the main factors affecting the surface roughness were speed, feed rate, depth of cut, and overhang. The surface roughness value decrease with the depth of cut, feed rate, and overhang was lower and increase the speed. The optimum condition was the speed of 1,700 rpm, feed rate of 0.06 mm/rev, depth of cut of 0.25 mm, and the overhang 25 mm. The surface roughness was 1.6387 μm. In the experiment, the results were confirmed. The Mean. Absolute Percent Error was 1.92 percent, which is less than 5 percent, so it is within the acceptable range. From the analysis of insert wear behavior by making holes in carbon steel grade S45C at optimum turning conditions with a turning time of 487 minutes, the insert was found to have wear on the surface or flank wear caused by strong friction between the workpiece and the turning insert.