Effect of Conical angle and Spindle speed on the Characteristics of Holes Machined using Friction Drilling Process

In the present investigation, holes in AA7075 aluminum sheets were drilled using friction drilling method. The effect of the tool rotational speed (spindle speed) and the tool conical angle on the hole dimensions were investigated. The friction drilling process was performed using tool rotational speeds of 3100 rpm, 3400 rpm and 3700 rpm. The tool conical region has hexagonal shape with conical angles of 25o, 30o and 35o. To evaluate the quality of the manufactured holes, the hole diameter, bushing height and wall thickness dimensions were measured. The analysis of variance (ANOVA) statistical method was used to evaluate the influence of the spindle speed and the conical angle. Moreover, models were developed using regression analysis technique to predict the hole dimensions. The results revealed that the maximum average busing height was about 7.945 mm exhibited by holes friction drilled using rotational speed and conical angle of 3700 rpm and 30o, respectively. While the maximum average busing wall thickness was about 1.325 mm exhibited by holes friction drilled using rotational speed and conical angle of 3700 rpm and 25o, respectively. The maximum hole diameter was 15.17 mm for a hole drilled using spindle speed and conical angle of 3100 rpm and 30o, respectively. Furthermore, the minimum hole diameter was about 15 mm for a hole friction drilled using tool spindle speed and conical angle of 3400 rpm and 30o, respectively.