The Determination of Empirical Model for Surface Roughness in Turning Process Using Design of Experiment

The purpose of this research is to determine the empirical model for surface roughness in a turning process. This process is performed in the final assembly department at a manufacturing company which supplies fluid dynamic bearing (FDB) spindle motors for hard disk drives (HDDs). The workpieces used were the sleeves of FDB motors made of ferritic stainless steel, grade AISI 12L14. A 2 factorial experiment was used to characterize the effects of machining factors, depth of cut, spindle speed and feed rate on the surface roughness of the sleeve. The results show that the surface roughness is minimized when the spindle speed and feed rate are set to the highest levels while the depth of cut is set to the lowest level. Even though the results from this research are process specific, the methodology deployed can be readily applied to different turning processes. As a result, practitioners have guidelines for achieving the highest possible performance potential. Key-Words: Fluid dynamic bearing (FDB), Full factorial experiment design, Hard disk drives (HDDs), Spindle motor sleeve, Surface roughness, Turning process