Abstract:
The purposes of this research were to investigate the factor that effects on the holes surface roughness of medium carbon steel AISI 1050 grade by using an internal grinding method. The independent variables included speed, depth of cut and feed rate. The dependent variable was surface roughness. The material used in the experiment was hardened medium carbon steel AISI 1050 grade with an approximate hardness of 51 + 2 HRC, the total of 54 specimens. The specimen shape was cylindrical with an internal hole with the diameter of 30 millimeters, 35 millimeters long and inside diameter of 20 millimeters. The grinding model used was white alumina oxide (WA 100 W-186) with the size of 13 x 19 x 6 millimeters. In the experiment, CNC Milling Machine (computer numerical control) was used for grinding process and one grinding model per one specimen. The speed was set to 3 levels included 3000, 6000, and 12000 rounds per minute. The feed rate was set to 3 levels included 150, 300, and 450 millimeters per minute and the depth of cut was set to 2 levels included 0.1 and 0.3 millimeters according to the designed conditions. Then, measure all surface roughness by measuring 3 positions per specimen and calculate the average surface roughness. The results found that depth of cut and the feed rate was significantly affected to surface roughness at the significance level of .05 and found that the interaction factors have no effect to the surface roughness significantly.